Q & A

Q & A

This page as an open thread for reader questions, especially questions about personal health concerns.

I am putting this page up as a way to share knowledge — my knowledge with questioners, but also so that others with similar concerns can read the conversation, and readers with relevant knowledge can chip in with their own thoughts.

Please keep in mind that I can’t research questions in any depth, so my answers should be considered tentative, incomplete, and subject to later correction. Also, I am not a doctor, and nothing I say should be construed as a substitute for medical diagnosis and treatment. I am only sharing opinions about disease origins and general therapeutic strategies which may or may not be applicable in any given case.

To get the page started, I’ll put up a few questions from recent emails. Here is an index by disease, with clickable links:

And here are my answers.

Chronic Lymphocytic Leukemia (CLL)


Been following your work on the PHD before the publication of the book and commented on my CLL and the usefulness of Vitamin D once on your blog and you responded to keep an eye on my Vitamin K intake, which I do now.. Am fortunate in a way to have my form of CLL as it indolent which gives me the opportunity to experiment without the pressure of undergoing conventional treatment. The PHD, I think, is helpful in this regard.

Wonder if you could point anything out to me that may be useful. Anything at all. And I will be happy to share with you my results.

Surely you know of the helpfulness of green tea with CLL. You may not be familiar with research that points out that those with low levels of Vitamin D need treatment for CLL far sooner than those with elevated levels.

Feel strongly that your version of a ketogenic diet would be helpful but also feel I need some direction in this area. Do you have any suggestions?

Warmest Regards,


Hi A,

I remember your comment, thanks for writing back. I’m glad you’re enjoying our diet and wish you the best.

Thanks for the tips about green tea and vitamin D. Neither one surprises me.

Most likely CLL is caused by a viral infection. So enhancing viral immunity is probably a good idea. Good strategies may include: (1) low-protein dieting, which inhibits viral reproduction and can promote autophagy; (2) maintaining high vitamin D levels; and (3) intermittent fasting, which promotes autophagy.

Some food compounds have been reported to have antiviral effects. An example is green tea catechins, eg http://pmid.us/16137775, http://pmid.us/18313149, and http://pmid.us/18363746, and this could be why green tea is helpful against cancers, http://pmid.us/21595018, which are usually viral in origin.

I might search Pubmed for herbs and spices with antiviral effects, and use them abundantly in cooking, along with antiviral foods. Turmeric / curcumin is a good choice, this needs to be taken with black pepper to enter the body. See http://pmid.us/21299124, http://pmid.us/20434445, http://pmid.us/20026048.

Coconut oil / lauric acid also has some antiviral properties, so inducing ketosis with coconut oil could benefit you even aside from the ketosis. You could also try monolaurin supplements which may enter the body better and which some people have reported to help viral infections.

You might also try HDL-raising tactics as discussed in this series: HDL and Immunity, April 12; HDL: Higher is Good, But is Highest Best?, April 14; How to Raise HDL, April 20.

Another possible tactic is high-dose riboflavin with UV exposure on the eyes. This requires going outdoors at midday and not wearing glasses or contact lenses. Riboflavin+UV is toxic to blood-borne viruses, and the retina is a location where UV can reach circulating blood cells. Sun exposure will also help you optimize vitamin D.

That’s a few ideas, at some point I’ll do some research to come up with more and do a blog post. Do keep me posted on your results!

Best, Paul

Bloating, acid reflux, anxiety, depression, hypoglycemia, hypothyroidism, fatigue

Just came upon your website and had a question for you. I have had some health concerns for the last four years, bloating, acid reflux, anxiety, depression, hypoglycemia symptoms, female complaints (I am in my forties), thyroid antibodies at 333, weight gain around my middle and too tired to work out like I once did. I used to be fikiiled with energy and great health no depression or anxiety. My doctor thinks these symtoms are all from peri-menopause and wants to treat me with Zoloft.

Needless to say I have tried to avoid the Zoloft. I have tired every avenue out there to cure myself. Most recently the Primal type diet. When I eat no grains or dairy I get horrible hypoglycemia symptoms and don’t feel great like everyone else on a low carb diet. I feel weak and more anxious. Do you think your diet would be easier for me with the addition of rice and potatoes?


Hi G,

Yes, I do think our diet will be better for you. You should eat enough starches to avoid hypoglycemia.

The key thing for you is treating the infections which are consuming so much glucose and making you glucose-deficient if you don’t eat enough carbs. Whatever pathogen(s) this is, it seems to have infected your gut and caused the various gut problems; circulating pathogen-derived toxins and immune cytokines are probably responsible for the anxiety and depression. Hashimoto’s hypothyroidism may be either due to circulating toxins or a thyroid infection.

I would suspect some kind of protozoal or parasitic infection due to the hypoglycemia, but what I really recommend is getting your doctor to have a stool sample analyzed for pathogens. Metametrix has a good test. Once you know what pathogen to treat, and get on a better diet like ours, you should improve quickly.


I am writing on behalf of my mother … We live in Dhaka Bangladesh …

Before her illness, my mom was 105 lbs, 5 feet tall and always 10ft tall in spirit…. When she was diagnosed with Lupus at the age of 30, we were all overwhelmed and out of our depths. My beautiful, athletic mother was in a wheelchair and given 6 months to live….

The doctors has advised her to eat literally nothing, minimum protein (1 small piece of chicken/fish, limited to 20g protein per day), only 2-3 types of vegetable and 2-3 fruits and of course lots of carbs to apparently compensate for her failing KIDNEY and LUPUS. She is on tons of medication, no food except the wrong foods (carbs) and in chronic pain. She currently weighs 139 lbs.

Please advise. — S

Hi S,

I believe lupus is a catch-all diagnosis for a variety of conditions which are probably caused by undiagnosed infections. In the US the infections are usually bacterial. I’ve known several people with diagnosed lupus who were cured by antibiotic treatments – in one case the problem was Lyme disease (Borrelia). I have no idea what the likely pathogens would be in Bangladesh. If she does better on low carb and coconut oil, that indicates bacteria; if she does better on high-carb, that indicates protozoa.

A healthy diet is very important. It is very bad advice to “eat literally nothing,” it is essential to be well nourished. Protein is necessary for healing and immune function, and 20 g/day is too little. Fasting is good, but it should be intermittent – not starvation! She needs healthy fats, more protein, and lots of micronutrients. Eggs, shellfish, seafood, bone broth soups, vegetable soups, and fermented vegetables may all be helpful. Coconut milk is probably good for her. You should basically follow the program in our book.

I would try to put her on a good diet, give her a little time for kidneys and other tissues to heal, and then try antimicrobial medicines. Usually, if they’re not working, then you don’t notice an effect. Any strong effect, good or bad, means they are working. Bad effects mean that pathogens are dying and releasing a lot of toxins as they disintegrate. If this occurs, detox aids (salt, water, and one of cholestyramine/charcoal/bentonite clay; also glutathione supports and vitamin C) will help.

Please stay in touch and let me know how things go.

Best, Paul


Jersie wrote:

I’ve suffered from depression for decades. A few months ago, I decided to try the Dr. Kruse protocol for jumpstarting leptin sensitivity and 2 interesting things happened.

When I went very low carb – below 50 gm -. I had half-day periods where the depression suddenly lifted (something that has rarely happened otherwise). However, I also suffered from darker than normal periods.

I stopped the Dr. Kruse protocol after 6 weeks, and went back to regular paleo (approx. 200 – 300 gm. Carb/day). I’m now generally more depressed than usual, without the good periods.

These changes seem to indicate that I can have an influence on my depression with diet, but not sure what diet to try. Thoughts?

Hi Jersie,

I think your experience on very low carb is diagnostically telling.

I would interpret it this way:

  1. Your depression is caused by an interferon-gamma mediated immune response in the brain, probably caused by a viral or bacterial infection. This leads to tryptophan being directed away from serotonin and toward the kynurenine pathway. So you have a serotonin deficiency and kynurenine excess.
  2. A ketogenic diet is both therapeutic (promotes immunity against bacterial and viral infections) and mood-improving (clears kynurenine).
  3. However, you are at risk for hypoglycemia in the brain (especially if the infection is bacterial) and hypoglycemia causes irritability/anxiety and can aggravate depression.

So the very low-carb diet had mixed effects (ketosis, hypoglycemia).

What I would do is follow our ketogenic diet advice. Eat at least 50 g/day carbs from starches to get sufficient glucose, plus sufficient protein to reach 600 calories/day protein+carb, but add in large amounts of MCT oil or coconut oil. Also, do intermittent fasting – eat all the carbs within an 8-hour window; eat at least half the MCT oil in the 16-hour fasting window.

Once on a good diet, I might experiment with antibiotics to see if they relieve symptoms.

Please let me know how things go.

Leave a comment ?


  1. Hey Paul, NAC is no longer going to be available as a supplement. What can it be replaced with? Maybe R-ALA?

    • You can still get bulk NAC on various sites. I just ordered a couple of pounds for future use. All major sites have already removed it, but do a general search for bulk nac and sites will pop up.

      • Thank you I have followed your advise. But still all expire in 2024. I wonder if Paul can suggest a replacement.
        The fascistas have attacked us from another angle.

  2. Hi Folks,

    I’m a thirty-six year old male in very good health–I’ve been proudly following the PHD for many years. I’ve read that Paul aims for a ferritin level of 50-150 (or 130?) ng/ml, and gives blood regulary every few months. So, is my case healthy? I had my ferrtin tested on 8/15/19 at 54 ng/ml and I retested yesterday, 5/26/21, at 53 ng/ml. I hadn’t given blood in the inteval.

    I’d appreciate anyone’s comments.


    • Hi Nate,

      That either means that you are in perfect health (no inflammation, which would raise ferritin) or that you have a combination of inflammation with an offsetting iron deficiency. As long as you feel healthy and have iron sources such as beef in your diet it is probably the former.

      Best, Paul

  3. Thanks Paul, I really appreciate the reply. I’m reading all your blog articles in chronological order–I’m currently halfway (of course, I’ve read the book.) It’s interesting to see the metamorphosis of the PHD. Let me know if I’m being orthorexic, or when the next Retreat comes up. Thanks, Nate

  4. Hi Paul,

    Would you like to play detective? A good friend has some symptoms and may end up on medication indefinitely.

    For the past 2 months:
    – he’s been having palpitations and arrhythmias,
    – His heart beats slower than normal
    – He has what he describes as “attacks in which I get dizzy, sweat, have a choking sensation and pressure in my chest, and it feels like my heart is going to stop at any moment”.

    About him:
    – 25 y.o. male,
    – Athletic and very muscular,
    – Exercises almost every day,
    – Follows a western standard diet, pretty bad, maybe not terrible.
    – Otherwise, I don’t think he has a too stressful life. No stress at work, no alcohol, no sleep deprivation.
    – His blood test was pretty standard. Just bilirubin a bit higher than normal, but hepatic damage was discarded via ultrasound examination.

    I did my homework :razz:, so following the philosophy of this blog:
    – I suspect my friend is overtraining with respect to his body’s ability to overcome the stress, or relative to his nutritional status.
    – First step would be to put him into the PHD, make sure he doesn’t overexercise, etc., but very unfortunately he won’t make any big change on diet or the like.

    I’ve searched possible nutritional causes of arrhythmias and palpitations, which apparently are:
    – magnesium deficiency,
    – calcium excess,
    – salt deficiency,
    – potassium deficiency or excess,
    – methylation imbalances,
    – or anemia.

    He doesn’t have other symptoms that would raise suspicion. We know he doesn’t have anemia. But we don’t know his electrolytes in blood.

    Any suspicion, advice, hint? I appreciate any help. It’s been only two months, and we may hopefully solve this before further damage is done!


    • Hi Hector,

      I would have him adopt PHD and also get tested or treated for possible parasitic infections, e.g. https://medcrine.com/5-parasites-affecting-the-heart-and-their-manifestations.

      Best, Paul

      • Thanks very much, Paul.

        I elaborated this plan:

        0. He will try to implement PHD as much as possible.

        Then he will soon have an appointment with his doctor. Apart from the specific tests that the doctor deems necessary, he will ask to:

        1. Be tested for parasitic infections,
        2. Be tested for C-reactive protein,
        3. Be tested for Total cholesterol, LDL, HDL, triglycerides,
        4. As per my prior comment, to be tested for electrolytes K, Ca, Na. I’d have included Mg here, but decided not to because (i) the doctor may be reluctant to test for it because it’s not such a mainstream test, (ii) serum Mg is not very sensible to deficiencies, and (iii) he will supplement a (low dosage of) Mg anyway.

        Do you agree with 2, 3, 4? I’d have though that 2 and 3 are very informative, yet he didn’t have those tested.

        Then, he will include some of your recommended supplements — not all due to budget:

        5. Magnesium 200 mg/d
        6. Ascorbic acid 1 g/d
        7. B-complex (I found pills without niacin but cannot avoid folic acid) 1 pill weekly

        Is there any other supplement you consider important for him, such as N-acetyl-cysteine, glycine (if he didn’t make collagen-rich soups), taurine?

        And finally:

        8. He will be wary of overtraining,
        9. He was doing intermittent fasting; I asked him to keep calories towards the morning and light hours, but not to prolong the fast if he feels hunger,
        10. Other general steps that are always health-promoting, such as circadian rhythm entraining, controlling stress, etc.

        I will update in the future to hopefully share good news. Thanks so much.

        Best, Héctor

        • (I recall some other nutrients you mention in your book relative to heart health, such as copper and zinc, but he will have those covered by eating whole food.)

        • For the sake of documenting my post, I mention that in the paleo community it seems like an emphasis of seafood, mainly because of its iodine and omega 3, is recommended for people suffering from palpitations and arrhythmias. He’ll try that too.

  5. What is the best time to practice intermittent fasting? Is it best to skip breakfast or dinner? I have read that eating breakfast can help entrain circadian rhythm, is this true? I prefer to skip breakfast but if there are advantages to skipping dinner I will switch.


    • Hi Shane,

      I know these answer from Paul very well because I have been working in implementing it:

      1. He believes that the best eating window is about 3 hours after dawn, and ends 1 hour before sunset. So e.g. if that was 6 am to 6 pm, that would be 9 am to 5 pm.

      2. He believes skipping breakfast will be harmful *only* if that leads you to eat late in the night. If not, it should be OK. On the other hand, I would say he prefers to move most of the calories towards the morning, and I know he emphasizes this e.g. in obesity (and maybe other conditions strongly affected by circadian-rhythm).

      3. I think he would agree. Again, I recall him saying that moving most calories towards the moon is preferable for circadian rhythms (although notice that technically *moving* calories can be done by *concentrating* calories during lunch and then eat less at dinner, even if you are skipping breakfast). And as I said I think he emphasizes it especially in unhealthy people who would be helped by circadian rhythm therapy. E.g., my mother is obese and once she was able to accomplish it he recommended doing two meals a day by skipping dinner (although I am missing if this is due to other reasons apart from circadian rhythms).

      Also, Seth Roberts discovered that he would tend to wake up about three hours before breakfast. He wrote “To ensure we’re active when food is available, [the food circadian oscillator] wakes us up about three hours earlier. If you usually eat at noon, for example, it will wake you up at 9 am”. Check: https://sethroberts.net/2013/12/11/sleep-summary-of-what-ive-learned/#more-12236

      I would say back in the day Paul was very interested by Seth discoveries (such as face-morning therapy to entrain circadian rhythms) and may have been influenced by some (when it already agreed with the evidence, as Seth Roberts was fascinating but had some weak ideas). The thing is that there is a discrepancy here, and I don’t know why.

      So, according to Seth’s theory we would wake up three hours before breakfast, but Paul recommends waking up about one hour before dawn, and start eating three hours after dawn, which would mean that we eat *four* hours after waking up, not *three*.

      Paul, if you are reading, can you clarify why? Do you think Seth was wrong on this one?


      Finally I’m pasting here two comments from Paul that may be helpful to you.

      [1] On 2016, he said:

      “We recommend having a personal 12 hour “day” that is shifted relative to the sun. This gives you time after work to cook dinner and eat well before the end of day.

      We personally use an 8 am to 8 pm day, 8 pm to 8 am night. On this schedule the best times to eat are between 11 am and 7 pm, the best times to sleep 11 pm to 7 am. Try to obtain most calories in the early afternoon. Try to exercise before eating.

      To implement this, set up bright 5500 K color temperature white lights throughout your home and office (or use a light box such as the one here, http://perfecthealthdiet.com/shop-circadian-rhythms/) and another set of orange-filtered bulbs for use in “night”. Switch to the orange bulbs about 3 hours before your bed time and after all eating and exercise is done.”

      [2] On 2013 (so old comment–he may have refined it), he said that the keys for circadian rhythm are:

      – Getting at least 2 hours per day of sunlight or very bright blue light distributed over a 10-12 hour period. Maintain lights as bright as possible over the rest of the period.
      – Getting 10-12 hours of essentially no blue light exposure; ie use amber light bulbs and f.lux on the computer, or wear blue-blocking amber goggles.
      – Eating meals within or close to the period of bright light exposure.
      – Sleeping at a consistent time and to a natural waking during the period of darkness.
      – Physical activity within the bright day period — preferably 30-40 minutes every day.
      – Social interaction and engagement during the day.


  6. Hi,

    Maybe someone can help me with this doubt:

    I see that milk contains a part of nonprotein nitrogen. In dogs, their milk contain ~7.5% of protein by mass and ~0.05% of nonprotein nitrogen, which accounts to ~4.4% of total nitrogen.

    So, in order to know how much protein-derived energy weaned puppies need, should I take this nonprotein nitrogen into account? As I understand it, yes, as this nonprotein nitrogen spares protein needs. If so, then how should I account for it? Is it as simple as adding 7.5% plus 4.4% so to consider that milk contains ~12% of protein by mass?

  7. Ok, so I see protein can be estimated as total nitrogen * 6.38. The 6.38 is the factor used for milk but will vary depending on the food, see table here: https://en.wikipedia.org/wiki/Kjeldahl_method#Applications

    So 0.055 g of nonprotein nitrogen per 100 g of milk will be equivalent to ~0,35 g of protein.

    The rest of the nitrogen (95,6%) will come from 7,5 g of protein per 100 g of milk, which is ~1.195 g of protein nitrogen.

    My confusion comes from this study [1] in which they state dog’s milk contain by mass 9.47% fat, 7,53% protein, 3,81% sugar, and 146 kcal. Yet they state “protein comprised 31% of milk energy”.

    I would have calculated 9.47*9+7.53*4+3.81*4 = 131 kcal, and 7.53*4/131 = 0.23, so that protein comprises 23% of milk energy, not 31%. Even if they didn’t account for the 0,055 g/100 g of free nitrogen, the difference is minimal, in which case 24% of milk energy would come from protein.

    So I don’t know what I’m missing, or maybe the study from 1984 is using old factors that are not used anymore… but I don’t think so, or then the difference would be brutal! If someone realizes, please do let me know.

    [1] https://pubmed.ncbi.nlm.nih.gov/6726450/

  8. Hi,

    Eric answered some questions by mail, and we are sharing them here for the interest of readers.

    Thank you, Eric, for taking the time to answer these questions, and for always making such enriching contributions and discussions!

    Three clarifications:

    – My post-interview comments will appear in square brackets, as in [this example].

    – My questions have been re-written for clarity, as in the original interview they contained contextual information not relevant now. Eric’s answers remain unchanged.

    – All URLs contain spaces after each dot, otherwise the SPAM filter was activated.

    Q: Are you following the Perfect Health Diet after all these years? What don’t you agree with?

    Yes, I still follow PHD. My main point of disagreement, which you likely know already from reading my comments on Paul’s blog, is that I am more suspicious than Paul is of purified nutrients. So I focus on foods like coconut rather than coconut oil, for example. I try to get all nutrients from food, and take far fewer supplements than PHD recommends — currently just vitamin C (and vitamin D in the winter when sunshine is scarce). I also eat significantly less red meat than Paul advises (although I do not avoid it entirely) — I think red meat is not a health concern, but I acknowledge that the data is sufficiently confusing that I would prefer not to take the risk in case I am wrong.

    [In a later comment, Eric made it clear that he is only talking about red meat, not meat in general.]

    Q: So, in 2017 you said you were implementing a food-only version of the Perfect Health Diet [for context, see: http: //perfecthealthdiet. com/recommended-supplements/comment-page-40/#comment-1758146]. Have there been any changes?

    My main corrections to my earlier comment are as follows:

    – Duck egg yolks are much richer in K2 than chicken egg yolks, and Jarlsberg cheese is much richer in K2 than other cheese. With duck egg yolks and Jarlsberg cheese, you can get K2 from food alone too.

    – I have switched from Pacific oysters to Atlantic oysters. Pacific oysters risk cadmium toxicity if eaten in large quantities; Atlantic oysters do not. Two Atlantic oysters per day (about 25 grams edible portion) provides sufficient zinc.

    – I think I overestimated how much soup stock and seaweed is necessary. I eat a bit less now (more like 2 or 3 sheets of nori, and 10 cups/week of soup stock).

    Q: I also recall that you consulted Paul Jaminet on the optimal amount of fiber. While the book suggests that about 1% of energy from fiber may be optimal [and in recent comment, Paul states 1-2% which is equivalent to 15-30 g of fiber], I think you found a mistake and argued for a higher amount. Can you clarify?

    Yes, 2000 calories of human breast provides the equivalent of about 50 grams of fiber, which I think is optimal.

    Q: Readers of this blog know that saturated fat is healthy, and the safest source of calories for our metabolism, as it does not exhibit the toxicity effects that excess carbohydrate or protein do [although of course any source of excess calories can cause damage, such as oxidative stress]. However, as the microbiota is further studied, some suggest saturated fats may promote populations of harmful bacteria, and that saturated fats are very good at driving endotoxins within the body. How do you think this fits in? [The idea I wanted to express is: Could saturated fat be healthy for our metabolism yet unhealthy for our bacteria, so that there is a practical limit at which saturated fat becomes unhealthy through microbiota-mediated effects?]

    No, I don’t think saturated fat, per se, is a cause for concern. I suggest you take another look at the randomized controlled trials in humans which look at the impact of varying saturated fat on mortality. (These trials are some of the older trials I mentioned in my previous email.) They are discussed in chapter 11 of Paul’s book (starting on page 120 in my edition).

    I would avoid purified nutrients, including purified saturated fat. You may find the following study interesting; it compares biomarkers after eating the same amount of saturated from either butter (purified) or cream (not purified): https: //pubmed. ncbi. nlm. nih. gov/26016870/

    The mechanism here is not clear, but endotoxin transport is a reasonable guess: In cream, saturated fat is enclosed in MFGM, and this presumably prevents endotoxins from dissolving into the saturated fat. Regardless, my takeaway here would be to avoid purified nutrients, not to avoid saturated fat.

    Q: Do you think the pulses that you recommended [or better said, determined to possibly be the least risky if well prepared] can be healthy as a staple? In your comments [for context, see: http: //perfecthealthdiet. com/the-diet/comment-page-16/#comment-1667447] you do mention possible hidden dangers, such as toxins not yet discovered. But could it be that the huge amount of epidemiological data in favor of pulses may make us less suspicious, because if they fail to detect problems, they may not exist or be of small importance? As an example, we have seen that the epidemiological data from the COVID vaccines has made us able to detect side effects that had a very low frequency [in reference to the 1/1000000 risk of a blood clotting disorder with the Johnson and Johnson vaccine].

    For safety of the COVID vaccines, we have data from randomized controlled trials measuring hard endpoints *and* epidemiological data — both of which tell the same story. For safety of pulses, we only have epidemiological data, and so our confidence should be lower.

    If eaten in sufficiently large quantities, pulses could also displace animal foods from the diet, thereby making it more difficult to obtain animal-associated micronutrients.

    Q: Electromagnetic fields (EMF) exposure has been a topic of discussion in the alternative health communities, including a part of the paleo community. Do you think it is a factor affecting health?

    No, I am not aware of any evidence that EMF radiation is an important factor in health.

    Q: Do you agree with Paul advice [for context, see e.g. the Perfect Health Retreat schedule: http: //perfecthealthdiet. com/day-perfect-health-retreat/] that to follow an artificial 12-hour “day” and 12-hour “night” that is shifted relative to the sun [and which you would simulate through blackout curtains, blue and green blocking glasses, healthy and time-appropriate artificial light when needed, etc.] would be the best approach to circadian rhythms?

    I agree with Paul here.

    Q: In the past you recommended a specific blue-free LED light to use at night that had no output below 560 nm [for context, see: http: //perfecthealthdiet. com/shop-circadian-rhythms/#comment-1743357]. In this comment, you mentioned you had a spectrometer with which you measured it, so I assume quality lighting is very relevant to you. However, in your comment you did not mention anything about flickering; do you consider it?

    I do not notice any flickering from these light bulbs.

    Q: …So, I assume that you don’t mind the flickering if its frequency is high enough not to be picked up by, let’s say, a phone slow-motion camera, right?

    Correct. I assume that flickering frequencies too high to notice are not an issue. I also always run light sources on maximum brightness, and in particular never with dimmer switches.

    [I will comment on this for people unfamiliar with flickering. The thing is that most dimmable lights are not actually changing their intensity, but rather altering the time they stay on and off. A possible example is that a light set at 50% is actually flickering on half the time and off half the time, at frequencies that the eyes cannot notice. This is indeed a simplification: the flicker effect depends on the shape of the curve (the change in intensity can be abrupt or sinusoidal as in incandescent), the frequency, and the magnitude of the variation in intensity. Flickering influences health, as you can read in the IEEE Recommended Practice.

    Flickering will be minimized at high brightness in any dimmable screen or bulb, and it will matter if your device uses a PWM system to regulate the brightness (in opposite to a DC dimming system, usually marketed as flicker-free screens, but that indeed are also flickering but at a few orders of magnitude higher frequencies). So, you could set up the screen of your PC to the maximum brightness in order to reduce or avoid flickering, and reduce light output to your liking by software by using programs such as “Pangolin Screen Brightness” or “Iris” (similar to F.lux but with more functions).]

    Q: In addition to the PHD blog–which is now on hiatus due to the Jaminets’ cancer research activity–what other sources of information in the matter of health do you follow nowadays?

    Currently, I do not regularly follow any diet-related sources closely, although I do sometimes check Paul’s blog in case there is interesting discussion or updates. I have already researched diet pretty thoroughly, and successfully solved some chronic health issues by doing so. But at this point, I feel that I have reached the point of diminishing returns. So any time I want to spend improving my own health is probably better spent in other ways, such as on exercise (a task at which I still struggle).

    When I was actively following diet-related sources, the only source I found consistently accurate was Paul’s work. Chris Masterjohn also has some interesting ideas, although I would treat what he says as interesting speculation and worthwhile topics for confirmatory research, not as advice I would necessarily follow.

    Q: How is it possible that the official nutrition recommendations, produced by prestigious institutions full of such intelligent and educated professionals, are so wrong?

    Decades ago, nutrition researchers could conduct randomized controlled trials in humans that lasted long enough to measure hard endpoints. This means randomly assigning the participants to eat different diets for several years to see which group lives longer. We have such experiments testing various dietary interventions, all of which support PHD advice. This includes replacement of animal fats with vegetable oils (shown to be harmful), and increasing whole grain consumption (shown to be probably harmful), and others. Some of these experiments were done in prisons, mental hospitals, or other similar institutional settings, which ensures that the participants have good compliance.

    But today conducting such an experiment would at least be considered unethical, if not entirely illegal.

    So why is academic nutrition science so unreliable? Well, what do you think happens to a scientific field when it becomes illegal to run good quality experiments?

    Who stays in the field, and who switches to another field? You can’t get funding or employment unless you do new research. And when the new research with poor methodology contradicts older good quality research, then what are you going to base your dietary recommendations off of? If you admit the older studies are right, and your new results are wrong, well, then good luck obtaining funding or employment.

    Q: What is your religious stance? Do you believe in God, are you agnostic or atheist?

    No, I do not believe in god or follow any religion. If you are interested in the sorts of philosophical questions that religion tries to answer, I would recommend reading “Good and Real” by Drescher, which I think is approximately correct. I don’t have anything to say about where I think it is wrong (not because I think it is completely correct but because such questions interest me less than practical questions about what to eat).

    Thank you!

    • I’m so appreciative of the knowledge you’ve shared with us.

      I would just like to note that if everything I’ve learned from reading Eric’s comments is correct then Chris Masterjohn has been misinterpreting and misrepresenting a significant amount of data over the past several months.

      Thank you Eric and Hector for making this worthwhile discussion public and for your time! 🙂

      • Hi Alexandra, thank you for your kindness. I can say the same. I feel a huge sense of gratitude to people like Paul and Eric, and other discreet commenters, who share so much selflessly and allowed us to learn such important things. They are among the people who have influenced my life the most for the better, and I’m saying this without the tiniest hint of exaggeration.

    • Hi Eric,

      I don’t know if you ever expressed it, but I’m interested to know why you personally reject supplements (i.e. why you feel suspicious about them).

      A few arguments come to mind, but I don’t know if I’m missing more; and I’d like to know which ones you are more worried about:

      1. Differences in the behavior of isolated or supplemented nutrients versus their natural variants found in the food matrix. For example: lack of other synergistic compounds, possible unexpected effects (such as compounds that in abnormal concentrations may have pharmacological effects), and so on.

      2. Possible errors or frauds: supplements with concentrations much higher or much lower than specified. Contaminants. Undeclared substances. Etcetera.

      3. Residual contaminants (these are unavoidable and there will be traces), e.g. from reaction agents, or from the manufacturing process (solvents, etc.), or from the decomposition of molecules.

      4. Inability to follow instinct in food selection. That is to say, if our diet is made up of natural foods, it is to be expected that we’d feel attraction towards those that contain what we need, and repulsion to those that produce excesses. But if we take nutrients in the form of supplements or pills, this relationship with food is broken.

      5. Conservation conditions. Some vitamins degrade with humidity, heat, light, and you do not know if ideal conditions have been respected before the supplement reaches you.

      6. Poor quality. I assume that in purified molecules there is no such thing as “poor quality” (although a poor quality supplement may contain more contaminants, for example — and of course cheap supplements will use less bioavailable molecules, but this can be prevented by reading the label). But in natural products there is: like fish oil, which is rancid; or fruit powders, which may have been processed aggressively, or are made out of poor quality raw material, or contain yeast, etc.

      7. Additives. Artificial celluloses, silicon dioxide, titanium dioxide, magnesium stearate, and similar substances that are generally used as bulking agents, or to encapsulate, or to improve machinability.


      • I was also wondering about:

        8. Supplements in molecular forms that may differ from the forms present in nature or alter the proportion that is found in a natural diet.

        That is, I assume that real foods contain a diversity of forms, e.g., the same mineral may have many chelates. However, when you supplement e.g. magnesium, you typically only supplement one form. I wonder if this difference only affects bioavailability, or if it may have other effects as well.

        [For one, I have heard that certain magnesium chelates are better absorbed by the brain, and that intrigues me as that would indeed indicate that we wouldn’t be emulating the magnesium found in natural foods, which may carry (perhaps unknown?) risks. I suppose also that the body is able to ionize and use magnesium as it pleases, so if certain supplemental forms are destined for the brain it is because we are only facilitating the work the body would do itself, not overlapping it (if I’m making myself clear).]

        • I just recalled that the book discusses the two most common forms of selenium: selenomethionine and selenocystheine. The former has potential detrimental effects, so PHD favours selenocystheine (which is naturally found in animal products).

          How do we know that similar issues don’t arise for e.g. the many forms in which magnesium or zinc can be found in supplements? I recall Chris Masterjohn arguing against zinc picolinate, so I’m assuming there is room for debate on these issues. So is this concern legitimate?

      • Hi Hector,

        Your list of reasons seems pretty good. Here are a few of my thoughts, elaborating on your concern #8 and adding two more of my own:

        8. This concern extends to vitamins as well minerals. For example free pantothenic acid basically does not exist in the food supply; it is found near-universally as either part of the coenzyme A or 4′-phosphopantetheine molecules.

        9. Free micronutrients may be accessible to the microbiome at an earlier stage of digestion than their food-bound counterparts.

        10. A diet that is missing many known beneficial compounds is likely to also be missing other unknown beneficial compounds. For example the best food sources of pantothenic acid also contain considerable quantities of ergothioneine. If you are supplementing pantothenic acid should you also supplement ergothioneine? This is not one of Paul’s recommended supplements; should it be? How many other things are missing?


  9. Is this diet good for bariatric patients and what supplements do you recommend?

  10. Hi Paul,

    this preprint (not peer reviewed) is doing the social media rounds at the moment… along with comments about Cancer… & TLR4.

    “The BNT162b2 mRNA vaccine against SARS-CoV-2 reprograms both adaptive and innate immune responses”


    I dont pretend to understand any of it.
    As Cancer is being mentioned (along with TLR4), I thought of you.

    When you have a chance, could you take a look please… & comment back.

    Much Appreciated.

  11. Hi Paul

    I believe I read one of your comments in the blog, that was saying the 1lb starches and 1lb meat per day is based on a 2000cal diet, does it mean I would need to increase those if I’m on a 3500cal diet, or just adding the extra fat for the added calories? perhaps breaking down the 3500cal on 50%fat/30%carbs/20%protein?

    thank you

    • Hi Gianluca,

      I would say your basal calories should be roughly covered by the calorie split of 55% fat, 15% protein, and 30% carbohydrate. To do so, generally you want to keep the volume of starch and protein sources equal, as the volume of natural foods generally fit in these proportions. Then, eat vegetables and fat sources according to appetite — do keep fat sources around your menus, as egg yolks, avocados, coconut milk, nuts, a bit of oil for cooking, and so on, apart from the fat naturally found in animal foods.

      I would not go beyond 600 calories of proteins per day. Arguments are found in the book. (This is actually implicit in the previous advice.)

      The extra calories spent as a result of exercise should come from carbohydrate; as a rule of thumb, say 300 to 600 calories per hour of exercise.

      Better than keeping an average consumption of calories per day, it is good to overeat during exercise days, and sightly undereat during rest days.

      Finally, alter these ratios according to your personal preference. Don’t feel obliged to do what looks good on paper. E.g. if you feel protein sources start to be unappealing, you will know you are getting too much protein.


      • BTW, I think fruit is also to be scaled by those proportions. Fruit is helpful to replenish collagen for someone who exercises.

      • thanks Hector. If I’m understanding well, to reach my 3000/3500 cal per day then, I should only increase my fat and carbohydrates, which at 30% of energy comes at either at 225 or 260gr of carbs, paraphs with the 260gr on my training days.

        what do you mean by keeping the volume of starch and protein equal? sorry to overloading you with questions, but Paul in the book recommends .5 to 1.5 of meat per day, I have never understood if it is a raw or cooked measure? I also don’t find the protein recommendation specific, as there is a substantial difference in the protein content of 1 lb lean meat vs 1 lb of fatty meat, what do you recommend to count macronutrients?

        I see your comments all over the blog, are you working with Paul?

        • Hi Gianluca,

          I would do this:

          – Calculate your expenditure on rest days (days in which you don’t do intense physical activity). Use the Mifflin St. Jeor equation or similar.

          – Multiply that number by 0.55 (or 55/100) to obtain the fraction of calories that should come from fat, 0.30 for carbohydrates, 0.15 for protein.

          – Convert to grams by dividing fat calories by 9, carbohydrate calories by 4, and protein calories by 4 as well. Those are the grams of each macronutrient that you will need on rest days.

          – For exercising days: per each hour of intense exercise, add 300 to 800 calories from starches and some fruit (or more if you are an elite athlete) depending on your size and intensity of exercise. You could estimate whether to go for the upper limit or the lower limit by being aware of your breathing rhythm, fatigue, and appetite.

          – Once you got the numbers, how do they translate to real food? You must figure out rules of thumb to ease daily life, otherwise, you will get crazy. (Anyways, trying to be too precise would backfire; your preference towards foods is an instinct that will tune-fine your proportions better than you can, as long as your diet is based on foods that resemble those with which your instinct could co-evolve.) If you check the content of starch for tubers, sugar for fruits, and protein for animal foods, you will realize that by eating the same weight of them you’ll achieve these proportions. Take this example: 1 lb of potato, 1 lb of grass-fed meat, and 1 lb of banana would account for 96 g of starch, 56 of sugar, and 100 g of protein. For every 2,000 calories, PHD prescribes 100 g of starch, 50 g of sugar coming from fruit (which accounts for 25 g of fructose), and 50 to 150 g of protein. So, you see that with this rule you can approximate the proportions of the PHD easily. You don’t even need to weigh your food because the density of natural foods is approximately constant; so instead, you do good imagining the liquid volume of your food, and then try to roughly eat the same volume of fruit, starch, and animals. For the fat, eat it according to your hunger.

          When we talk about the weight of foods, we are talking about their raw weight (not cooked). Except for foods that are purchased dry, e.g., rice, in which case you want to measure the weight once cooked.

          You will notice that for some foods, if cooked gently, their raw weight is the same as the cooked weight (e.g., steamed potatoes and most vegetables). I would say meat however can lose about 30-40% of its original weight when cooked; offal will lose about 50% of its weight, and bivalves and octopus will lose even more.


          Let’s imagine we have a 20-year-old male, 70 in, and 175 lb, which on rest days still walks a few kilometers, so that he keeps a light exercise level. The Mifflin St. Jeor equation would estimate expenditure of 2,500 calories. So the caloric split would be 2,500*0.55 = 1375 calories that should come from fat, 2,500*0.30 = 750 calories that should come from carbohydrates, and 2,500*0.15 = 375 calories that should come from protein. This is for the rest days. (I apologize that in my previous comment I said “basal expenditure”, which is not precise, as it can be understood as “Basal Metabolic Rate (BMR)” which is another concept – for this example, BMR would be only 1,810 calories.)

          Now, on active days, let’s imagine he does two hours of intense exercise, which adds about 1,000 calories. So in total he will be eating about 0,75 lb to 1,25 lb of meat, 1,25 lb of tubers, and 1,25 lb of fruit, and some vegetables; plus 2 lb of tubers and fruit on exercising days. He can do so by eating three meals on rest days, but four meals on exercising days. Of course, some people won’t have that much appetite, so they could eat cooked vegetables instead of raw, some rice instead of potatoes, and so on.

          Regarding protein, as per the discussion in the book, there is little reason to eat more than 600 calories a day, at least if some carbohydrate is consumed.

          By the way, vegetables also contain some proteins. When I did my calculations, I think something like 30% of my protein intake came from all other foods besides animals. So, soemone muight think they are obtaining e.g. 100 g of protein if they are only considering meat, but they may be neglecting 10-30 g of protein that adds up from other foods.

          So again, don’t worry too much about being specific. Our appetite for protein is pretty well driven. Yes, you may choose cuts that are lower in protein some days, but you will chose others that are higher in protein other days. If you were continuously eating less protein than you need, you would really fancy a steak. So you can’t really get it too wrong; but even if you did, variability can even be beneficial as it probably exerts a hormetic effect on the body.

          Check some tables of composition of meats in order to get references on how much protein and fat they contain, if that is to help.

          Finally, this all seems much more difficult than it is. But don’t panic. You can use Cron-o-meter or other food- and calorie- tracking tools during a few days to check that you are doing it well. It will train your eye as well, so that you will soon realize that you can make good precisions on the fly.

          If something was still not clear enough let me know.


          • Hector

            I really appreciate the detailed explanation. I do generally, tend to overthink when planning the diet, and always think of getting in the perfect numbers I need of macronutrients, so thank you for giving some ideas on how to put everything together.

            I would basically count my energy expenditure on “rest days”, then calculating my energy expenditure on “training days”, then calculate my 30% of energy in carbohydrates for both days, protein the same at 150gr, then probably adjust fat to appetite. I think this is a good plan?

            I generally have three meals and maybe a snack or two, on my training days I’m thinking to opt for a carbohydrate powder that digest into glucose, to drink after training when very little insulin is needed for glycogen repletion.

          • I would be wary of carbohydrate powders.

            I think it is not physiologically normal to eat during or just after exercise. E.g., I know endurance runners who have digestive problems from ingesting carbohydrate fluids during training. If we are not talking about resistance training, you may not need it either. The metabolic window appears wider than previously thought. If you train on an empty stomach, perhaps it does make sense to eat shortly after training, but we are talking about an hour, not minutes. If you train without fasting, then I don’t think it’s necessary – just eat more calories that day in order to signal your body abundance of resources to build muscle.

            Some carbohydrate powders may be problematic on their own. Maltodextrin seems to impair cellular anti-microbial defense mechanism; to enhance cellular adhesion and biofilm formation in the gut; to enable microbes to adhere to the gut epithelium; and alter the microbiota by promoting the colonization and extension of pathogenic species such as adherent invasive E. Coli (AIEC). See: https://dash.harvard.edu/bitstream/handle/1/25658375/4615306.pdf?sequence=1 and pone.0101789 1..10 (storage.googleapis.com) to directly access two papers.

            So, if I had to choose one carbohydrate powder, I think the safest is dextrose or dehydrated glucose, which is pure glucose too but in a simpler form.
            In any case, I would prefer real food (even if it’s white rice), and I would work on ways to reduce the satiety of the food so I could eat more. You could have a smoothie for one of your foods.

            Notice too that glycogen repletion is best when there is some fructose in the mix, see this: http://perfecthealthdiet.com/2012/01/is-it-good-to-eat-sugar/

            Finally, for anybody training a lot, one has to accept that too much exercise and some measures to support such levels won’t be health-promoting but performance-promoting. You have to choose how to balance both aspects. Of course trying to be well fed and well rested is essential, as those will make anybody more resilient to the stress of exercise (and will promote performance too).


          • thanks for that paper, I was actually thinking about maldodextrose!

            I am involved in resistance training, after training there is a 90min window where any ingested carbohydrates will have a minimum effect on insulin, glucose is transported to the cells for muscle glycogen storage, via an enzyme instead which I do not recall the name of it. That is why I was thinking about a glucose drink perhaps mixed with some fat, then my usual meal with starch/protein 90min or so after the drink.

            what do you think then adding my extra carbohydrates on the “training days” with bananas only? paraphs too much fructose? I already have a banana or two for breakfast, then sometimes another one in the afternoon.

            I get 70gr of carbohydrates from starch lunch and dinner, with rice or sweet potatoes. Would another option be just adding more rice/sweet potatoes to my lunch and dinner on training days, or eating too much starch in one sitting may be problematic for insulin/glucose levels?

            thanks Hector, I promise I will leave you alone now!

          • Hi Gianluca,

            Paul would recommend that you eat fruit and potatoes in roughly equal proportion, e.g., 1 pound of potato and 1 pound of fruit. See this comment: http://perfecthealthdiet.com/2010/10/perfect-health-diet-for-athletes/#comment-1761520

            To get 1,000 calories from bananas, you would need 1.2 kg of banana without refuse. That would add up to 73 g of fructose, so in total you would be consuming 100 g of fructose. I think that is excessive.

            Simplified, it seems like fasting depletes liver glycose, exercise depletes muscle glycogen. (But there are paths with interaction of both systems, e.g. the Cori cycle.) So that raises the question: is fructose less harmful if eaten when your liver is depleted of glycogen?

            I wish I could answer with precision, but I’m ignorant of the fructose metabolism. Anyways, as fructose must still be absorbed and metabolized by the same ways, we can expect about the same harmful effects. Think of endotoxemia, uric acid production, or getting fructose in more rapidly than our liver can dispose of.

            By the way, the harmful effects of fructose seem aggravated by a vitamin D deficiency and high-fat intake. Probably the problem is not fat in general, but PUFA. PUFA is very fragile and fructose is very reactive — a bad combination. SAFA is not fragile.

            Even if fructose were harmful, in the end we have to get our calories from somewhere — i.e., choosing the lesser evil once you ponder cons and advantages. So I would just go with Paul’s recommendation, and eat about equal parts fruit or safe starches.

            Actually, in your case, I would tend to favor a bit more of safe starches over fruit, in part because insulin signals muscle growth. Also, some people have digestive problems with fructose, especially when consumed apart from meals. So maybe if you need to eat many calories, fructose could add up in your food intakes — starch is much safer in that regard.

            This paper might be of your interest, ‘Dietary strategies to promote glycogen synthesis after exercise’, https://pubmed.ncbi.nlm.nih.gov/11897899/

            Feel free to engage in conversation as much as you want. I’m learning too. This forum works a bit like that: ask and you may not get an answer. (That’s what makes it addictive.) But always, do ask! 😀


          • ”…exercise depletes muscle- [as well as liver-] glycogen…”

          • thank you Hector. Do you recall Paul taking about a safe maximum carbohydrates intake per meal? it may seems more convenient to add more starch into my meals on my training days, that would possibly bring a meal to about 180gr or Carbohydrates, how do you see this? I always thought we should consume small amounts of carbohydrates per meal, not to increase insulin and blood glucose postprandial so much, but perhaps on training days this would not matter. what are you thoughts?

          • Hi Gianluca,

            I’m surprised that for resistance training you need such caloric intake. It is certainly possible if you train a lot or are large. But given the case, I would wonder if it is optimal for achieving your goal.

            What is your caloric expenditure on rest days and training days? Do you know your VO max or your HR max? Do you train with a chest band e.g., POLAR H9/10?

            “Do you recall Paul talking about a safe maximum carbohydrates intake per meal?” I’m not aware; I would say that the “safe maximum” is circumstantial.
            I do remember him saying that even diabetics should be able to handle about 600 calories from carbohydrates per day; that makes sense in the light of the following discussion.

            It is my understanding that most problem with safe starches come from either eating them in amounts not appropriate for actual body needs, or them producing hyperglycemia. Let’s review these two points.

            Regarding carb body needs: Per the book arguments, a sedentary person will need about 600 kcal (if we take 2.000 kcal as a reference). Physical activity will increase carb needs. How much? It depends on its intensity. Low-intensity activities will consume mostly fat, and high-intensity activities will consume mostly glucose. That is discussed in the book. The important point here is to notice that, for someone who is burning through exercise e.g., 1,000 kcal of carbs, their needs are 1,000 + 600 kcal. So that person will do fine eating that amount. In other words: from a body perspective, if you define “moderate intake” of carbs as “the amount that your body needs”, then eating such amount will be a moderate intake, not high. (Diseases may increase these needs as well, e.g., from immune system activity.)
            Regarding hyperglycemia, notice is relatively modifiable. The book discusses ways to decrease hyperglycemia: cook them gently, avoid industrially prepared foods, eat starches with fat, eat starches with vegetables; and eat starches with acids, especially vinegar. Also mentioned in the book: do not have starches as a snack, generally; eat your starches cooled and, if desired, reheated gently; distribute your sweet plants and fruits in your meals so that there is a little fructose in each one.

            A few more tips:

            a) Spread your carbohydrates throughout your meals (except for the post-workout meal, which may be richer in carbohydrates).

            b) Order is important. Favor eating vegetables/vinegar first (e.g., a salad), and carbohydrates/sugar last (e.g., a dessert). See https://care.diabetesjournals.org/content/38/7/e98? and https://pubmed.ncbi.nlm.nih.gov/30381620/

            c) It is best to eat after exercising (but if the activity is intense, then do not eat immediately but wait until your gut feels like eating) or walk 10-20 minutes after eating.

            d) Get plenty of rest. At mealtimes, eat calmly and avoid stress.

            This an interesting webpage with further information: https://www.glucosegoddess.com/science

            The author from that website has a continuous glucose monitoring (she’s not diabetic though) and publishes results from n=1 experiments, see https://www.instagram.com/glucosegoddess/

            Other problems from carbs are circumstantial, e.g., infections or dysbiosis that thrive on carbs; or metabolic syndrome that impairs glucose metabolism.

            For the amounts that you need, I would also wonder what your genetic stance is. If you have fewer copies of the gene AMY1, you may tolerate starch poorly. But you don’t have to spend money on genetic testing; you can just pay attention to your ancestry (were they heavy starch consumers?) and in your sensations after eating starch, even after applying all the steps that lower its glycemic index (e.g., do you feel awful after eating? Do you have cravings 2-3 hours after a meal?).

            Perhaps you have seen these studies in which participants eat 50 g of carbohydrates from potato and 50 g of carbohydrates from fat. The peak glucose decreases, but in return, glucose and insulin stays elevated longer. Denise Minger talked about those here (minute 37 or so): https://youtu.be/qBBtQ4QwWxg?t=2092

            I haven’t looked at these studies. But so far what is reported does not make much sense to me. It is unfair to compare a meal with 50 g carbs vs a meal with 50 g carbs and 50 g fats. The second meal would contain more than triple the calories!

            Anyways, the steps previously discussed will diminish the height of both glucose and insulin spikes. (Not the area under the curve; but anyways, what you are manipulating through these tips is the rate at which carbs are absorbed – if you were diminishing the area under the curve, that would mean that you are not digesting your carbs.)

            It is my understanding that high blood glucose concentrations are proportionally much more harmful than lower amounts spread over time. So, it is in fact the spikes what you want to minimize. Apart from that, do intermittent fasting so that your insulin is not always elevated, so that you are not always signaling your body to “grow! grow!”

            By the way, eating most of your carbs on training days is called “carb cycling”. It has proven to affect body composition positively versus eating the same amount each day. However, if you feel like you need to eat too much in training days, I’d not hesitate to forgive a little on those days and eat a little more on rest days; i.e. to average your caloric intake a bit more.


          • Hi Gianluca,

            I’m surprised that for resistance training you need such caloric intake. It is certainly possible if you train a lot or are large. But given the case, I would wonder if it is optimal for achieving your goal.

            What is your caloric expenditure on rest days and training days? Do you know your VO max or your HR max? Do you train with a chest band e.g., POLAR H9/10?

            “Do you recall Paul talking about a safe maximum carbohydrates intake per meal?” I’m not aware; I would say that the “safe maximum” is circumstantial.

            I do remember him saying that even diabetics should be able to handle about 600 calories from carbohydrates per day; that makes sense in the light of the following discussion.

            It is my understanding that most problem with carbs come from either eating them in amounts not appropriate for actual body needs, or them producing hyperglycemia. Let’s review these two points.

            Regarding carb body needs: Per the book arguments, a sedentary person will need about 600 kcal (if we take 2.000 kcal as a reference). Physical activity will increase carb needs. How much? It depends on its intensity. Low-intensity activities will consume mostly fat, and high-intensity activities will consume mostly glucose. That is discussed in the book. The important point here is to notice that, for someone who is burning through exercise e.g., 1,000 kcal of carbs, their needs are 1,000 + 600 kcal. So that person will do fine eating that amount. In other words: from a body perspective, if you define “moderate intake” of carbs as “the amount that your body needs”, then eating such amount will be a moderate intake, not high. (Diseases may increase these needs as well, e.g., from immune system activity.)

            Regarding hyperglycemia, notice that glycemic index is relatively modifiable by combining foods; and the rate at which you store glucose –so that it does not reach critical circulating concentrations– is actionable too.

            The book discusses ways to decrease hyperglycemia: cook them gently, avoid industrially prepared foods, eat starches with fat, eat starches with vegetables; and eat starches with acids, especially vinegar. Also mentioned in the book: do not have starches as a snack, generally; eat your starches cooled and, if desired, reheated gently; distribute your sweet plants and fruits in your meals so that there is a little fructose in each one.

            A few more tips:

            a) Spread your carbohydrates throughout your meals (except for the post-workout meal, which may be richer in carbohydrates).

            b) Order is important. Favor eating vegetables/vinegar first (e.g., a salad), and carbohydrates/sugar last (e.g., a dessert). See https://care.diabetesjournals.org/content/38/7/e98? and https://pubmed.ncbi.nlm.nih.gov/30381620/

            c) It is best to eat after exercising (but if the activity is intense, then do not eat immediately but wait until your gut feels like eating) or walk 10-20 minutes after eating.

            d) Get plenty of rest. At mealtimes, eat calmly and avoid stress.

            This an interesting webpage with further information: https://www.glucosegoddess.com/science

            The owner of that website wears a continuous glucose monitoring (she’s not diabetic though) and publishes interesting n=1 experiments with regard to glucose spikes after eating. See https://www.instagram.com/glucosegoddess/

            Other problems from carbs are circumstantial, e.g., infections or dysbiosis that thrive on carbs.

            For the number of carbs that you describe, I would also wonder what your genetic stance is. If you have fewer copies of the gene AMY1, you may tolerate starch badly. But you don’t have to spend money on genetic testing; you can just pay attention to your ancestry (were they heavy starch consumers?) and in your sensations after eating starch, even after applying all the steps that lower its glycemic index (e.g., do you feel awful after eating? Do you have cravings 2-3 hours after a meal?).

            Perhaps you have seen these studies in which participants eat 50 g of carbohydrates from potato and 50 g of carbohydrates from fat. The peak glucose decreases, but in return, glucose and insulin stays elevated longer. Denise Minger talked about those here: https://youtu.be/qBBtQ4QwWxg?t=2092

            I haven’t looked at these studies. But so far what is reported does not make much sense to me. It is unfair to compare a meal with 50 g carbs vs a meal with 50 g carbs and 50 g fats. The second meal would contain more than triple the calories!

            Anyways, the steps previously discussed will diminish the height of both glucose and insulin spikes. (Not the area under the curve; but anyways, what you are manipulating through these tips is the rate at which carbs are absorbed – if you were diminishing the area under the curve, that would mean that you are not digesting your carbs.)

            It is my understanding that high blood glucose concentrations are proportionally much more harmful than lower amounts but spread over time. So, it is in fact the spikes what you want to minimize. Apart from that, do intermittent fasting so that your insulin is not always elevated, so that you are not always signaling your body to “grow! grow!”

            By the way, eating most of your carbs on training days is called “carb cycling”. It has proven to affect body composition positively versus eating the same amount each day. However, if you feel like you need to eat too much in training days, I’d not hesitate to forgive a little on those days and eat a little more on rest days; i.e. to average your caloric intake a bit more.


          • Hi Hector

            this is the calculator I generally use for my self https://www.niddk.nih.gov/bwp. it is pretty accurate.

            I think I should actually try the formula you suggested before, or some other formula I do not recall the name, and from there find out my normal caloric intake with low physical activities such as walking/yoga, and just adding more calories from my weight training days. Even on my “off” days, I don’t think I should go below 3000cal per days, but let me try the formula and see what happens.

            I handle starch pretty well, I sometime check my post prandial blood glucose (2h after the meal) and it is around 90/100

            I think this could be an ok option for extra carbs on training days, and it does not come with oxalates or other antinutrients https://www.transparentlabs.com/products/strengthseries-carb-powder?variant=32996735221853&currency=USD&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gclid=Cj0KCQjwt-6LBhDlARIsAIPRQcKPtz95AsnH7waYrUI9mnvda5Ed9CnS71lUV90yUbFSzjco4BbTctgaAvetEALw_wcB

          • I don’t generally measure my HR during a work out, unless it is a cardio work out

          • Hector

            check out this energy expenditure calculator for weight/resistance training at the bottom of the comment. Someone involved in this type of exercise, can therefore find his/her carbohydrate/caloric intake during normal days, then add the number of carbohydrates extra consumed during the weight training session, perhaps the 150/180gr Carbohydrates baseline suggested by Paul, plus the amount spent during weight training. For me, may equal about 95gr extra carbs


          • Hi Gianluca,

            yes that’s a reasonable expenditure

            in my previous message I had said that your caloric needs were ‘surprising’ only because I thought you meant 180 g cab per meal (which would equal eating ~1.2 kg of potatoes or 0.8 kg of white rice if you make 3 meals a day!). Now I understand you meant 180 carb in your post training meal. That’s OK

            real proof will come after ~two weeks when you realize if you are gaining or loosing weight. Until then, any calculation is a mere estimation

            btw thanks for the calculator, it’s useful


            P.S. I haven’t watched the video you recommended me; I plan to do so this weekend. Thank you!

          • Just to be clear, a correction:

            “… 180 g cab per meal (which would equal eating ~1.2 kg of potatoes or 0.8 kg of white rice if you make 3 meals a day!) per meal…”

            Another thing to correct, in case someone else read my previous comment:

            I had suggested that feeling tiredness after meals could signal carbohydrate intolerance. Now I’m not so sure. It seems like endotoxemia or high immune activity is more often the responsible; so maybe that would suggests dysbiosis/SIBO, high intestinal permeability, or intolerances mediated by IgG and such — those are sometimes specific to the gut mucosa, so may not show up in systemic food intolerance tests; and for sure not in food allergy tests as those are mediated by IgE and its symptoms can be life threatening

          • Hi Hector

            yes, 180gr carbs times 3 meals would be a bit too much, sorry for the confusion. What I probably meant was adding my extra carbs on my training days to one meal, paraphs lunch which generally comprises of 70gr carbohydrates, so a meal could be 70 + 90= 160gr carbs. Do you think it is a good strategy for adding my “training” carbs to a meal? or It would be best just having an extra meal post work out with my “training” carbs only?

            what have you seen perhaps from Paul, or in the forum, as to where to introduce the extra carbohydrates spent for exercise purposes. It would be good to see what Paul would think about this.

            I appreciate the conversation Hector

          • Hi Gianluca,

            By no means I’m knowledgeable on this, but it seems like the mix of carbohydrates and protein can replete muscle glycogen more efficiently, requiring a lower amount of carbohydrates and lesser frequency of intake.

            From the paper that I had suggested you: “[…] supplementing at 30-min intervals at a rate of 1.2 to 1.5 g CHO kg-1 body wt h-1 appears to maximize synthesis for a period of 4- to 5-h post exercise. If a lighter carbohydrate supplement is desired, however, glycogen synthesis can be enhanced with the addition of protein and certain amino acids. Furthermore, the combination of carbohydrate and protein has the added benefit of stimulating amino acid transport, protein synthesis and muscle tissue repair.”

            See this other paper [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905295/] “if both carbohydrate and protein are consumed, it is recommended that 0.8 g carbohydrate·kg-1 body wt plus 0.2 g protein·kg-1 body wt be consumed immediately and 2-hours after exercise during a 4-hour recovery period. The addition of protein to a carbohydrate supplement also has the added advantage of limiting post exercise muscle damage and promoting muscle protein accretion.”

            However, for evidence against that, I found this paper in cyclists [https://journals.physiology.org/doi/full/10.1152/jappl.2001.91.2.839?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org/]. Its title: “Addition of protein and amino acids to carbohydrates does not enhance postexercise muscle glycogen synthesis”. But after a glance I find this study odd: “The muscle glycogen concentration immediately after exercise was similar between the two trials [106 ± 19 (CHO) vs. 176 ± 31 mmol/kg dw (CHO+Pro)].” I don’t think 106 and 176 are similar numbers. The data [https://journals.physiology.org/doi/full/10.1152/jappl.2001.91.2.839?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org] suggest that both groups were repleting glycogen at the same rate, except that the CHO-Pro group had less to recover, so it ended sooner. Glycogen recovery rate will tend to zero the closer you get to the upper limit. Anyways, in that paper they were comparing the *same* amount of carbohydrates with us without addition of protein (maybe both groups had saturated the uptake by means of insulin and the like, i.e. reached peak glycogen synthesis rate?).

            If you decide to a have a post exercise meal of only carbohydrates, I saw several papers that recommend that to ingest about 1 to 1,5 g of high-glycemic carbohydrates per kg of body weight immediately after exercise. If delayed by two hours or more, glycogen synthesis is reduced by half. Some purpose about 0,5 to 1 g of high-glycemic carbohydrates per kg of body weight right after exercise, and *again* every two hours for four to six hours.

            These studies seem to be using glucose or starches that digest into glucose. But a mix of fructose and glucose (or rapid digesting starches) is best. Fructose metabolism occurs predominantly in the liver, so it may be that its metabolism inhibits the glucose uptake in the liver, leaving more available for the muscles. Whatever the reason, the data is clear. See this article from Paul Jaminet: http://perfecthealthdiet.com/2012/01/is-it-good-to-eat-sugar/

            I’m running out of time. So far, I have several doubts and a few comments. Resistance training may have a metabolic window of opportunity longer than other kinds of exercise. Perhaps it is not so demanding to eat just after exercise. Anyways, for a person who trains once every two days, is it necessary to work around optimizing glycogen repletion? That sounds unlikely — by focusing so much in that aspect we must be missing the opportunity to optimize others. Anyways, I would not eat immediately after exercise but wait at least a few minutes — but if I had to, I would prefer some fruit or starch rather than protein, as it is easier to digest and does not require the secretion of acid.

            This paper seems interesting but couldn’t check it: “Fundamentals of glycogen metabolism for coaches and athletes”: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019055/

            The next day I will try to keep learning about it, and we might discuss what is the best strategy to build muscle at least health-wise. But you rather see what other people already said, e.g. Mark Sisson has probably written about it.


          • Thanks for that last study you attached. I didn’t read all of it, but this is a quote from it

            “If postexercise carbohydrate supplementation is not maintained, GLUT4 transporters are removed from the membrane after 30–60 minutes.41 In short, the reduction in muscle glycogen stores that occurs during exercise is a major driving factor for subsequent glycogenesis.69
            After exercise, the restoration of muscle glycogen occurs in a biphasic manner. During the first phase, glycogen synthesis is rapid (12–30 mmol/g wet weight/h), does not require insulin, and lasts 30–40 minutes if glycogen depletion is substantial”

          • I mentioned before that within 90 min after exercise glucose uptake is increased via GLUT4 and very minimum insulin is used for the purpose of restoring muscle Glycogen, and that is why the reason of a post work out meal.

            The quote I attached from the study, actually shows, if I’m understanding well. if Carbohydrates are ingested within 30/40min post exercise, there will be no insulin secretion to replenish muscle glycogen. Therefore, if we follow PHD recommendation for carbohydrates of about 150/80gr daily, I think it is a really good idea, to get the extra calories spent for exercise in carbohydrates, within the 30/40min window, and if it is not lunch or dinner time yet, I think these are two great product to use



        • By the way, I do not work with Paul. I am a sometimes-overzealous commentator!

          Hilariously enough, commenting on the blog has served as diagnostic data. As I keep improving my health, I realized I may have a brain infection, as I have an awful hard time concentrating, thinking, and recalling. E.g., I don’t have insulin resistance and I follow the PHD, and I don’t think I have sugar crashes, but I still notice symptoms of hypoglycemia in the brain that cause me to eat more often than I would need to. The mental state is awful. Low serotonin may explain a bunch of other symptoms as well. It is easy to get used to the suffering when you have been sick for many years, but suddenly one day you realize that living like this is NOT normal. And it’s a relief. I was immunosuppressed with drugs for 15 years, and four years ago I was so weak to nearly die (I’ve since been recovering) – this may suggest germs thrived on me during those times.

          Health is tricky in that you have to keep untangling one thing from another. And this extends to remedies as well. For example, if I understood correctly, ketosis would be good for an infection in the brain, and a good strategy might be to eat coconut milk for breakfast and dinner to prolong the effects of autophagy in the brain. But I may have fungal infections as well, and so far I do know I have a fungal dysbiosis, so I can’t have coconut milk yet.

          I’m reading old blog posts and other forums to see what the best plan would be for this issue. I will expose it when I’m done — hope Paul can provide feedback then! 😀


          • have you ever checked your hormones? low Pregnenolone can cause cognitive impairment, short memory loss, trouble concentrating etc…

          • Thank you, Gianluca — I will consider hormonal unbalances as well. My plan is to perfect diet and lifestyle, and then see what symptoms are left and what their explanation might be. Then self-experimenting and of course trying to get a doctor to actually diagnose and help. What an adventure this is! Fortunately, hope is with us.

          • most main stream doctors don’t have any clue about hormones, endocrinologist included. Don’t we see the same thing with nutrition as well? on my own journey to improve my health, I certainly understood nutrition and lifestyle are a piece of the puzzle, but hormones as well, they need to be checked, and incase balanced for proper health. When you are ready, please let me know and I can point you to some educational material and perhaps some doctors that know what they do in regards to hormones

          • Sure. Please do let me know. If there is any document, you can send it to me at zanonioideae [at] gmail [dot] com

          • the documents I’m thinking about are medical studies, but I see you know well your way in the medical literature.

            If you struggling with concentration, thinking, memory I would test at least for Pregnenolone, DHEA, Free and Total Testosterones. Quiet frankly, your symptoms seems to be more related to low Pregnenolone. I’m 35 now, I discovered years ago I had low Testosterone and then low Pregnenolone. I’m not sure about your age, and if you had any head trauma in the past, that may have effected Pregnenolone, but in the big picture of improving your health, based on your symptoms, it would be worth testing. If your levels come back fine, then you can keep focusing on chronic infections.

          • Hi Gianluca,

            Not that much. If you do have interesting studies or resources handy, I do appreciate them. That would redirect me and save much time.

            How did you solve your hormonal problem? What was the root cause?

            I’m in my 20s. Actually I did receive two important blows to the head. One when I was a child, so much so that I lost consciousness, bled a lot, and was left with a scar in the forehead–but not as cool as Harry Potter’s. (I was already in poor health and had been immunosuppressed for years.) The second one at work on the top of the head, not as severe, but also important.

            Whether any were sufficient to affect pregnenolone or produce internal hemorrhage, I am not able to judge.


          • I would tend to think that hormonal trouble would likely be a mediator, not a root cause in itself. Of course, that’s not to say that focusing on hormones during recovery wouldn’t be beneficial, as is the case in hypothyroidism and comorbidities, where thyroid hormones are essential for various systems required for recover e.g. the immune system, gut health, wound healing. So supporting the production of certain hormones or even temporarily supplementing them if done wisely could be a therapeutic strategy.

            Would you agree here?

            So far, I have three main hypotheses for these symptoms. Per the philosophy of this blog, the cause might be an infection, a nutritional deficiency, or toxins. (I would probably discard toxins in my case.)

            The fourth hypothesis is an ill adaptation to an ill environment. The biggest culprit, probably, would be new technologies.

            Just as the food industry has found a way to use our instincts against us, the technological and software industry has done the same. (I could say “social media,” but that would be naive — even e-mail providers use similar strategies.) Simply put, if a company doesn’t play by those rules, it can’t compete in the marketplace. So, there’s an artificial selection that plays against people.

            I wouldn’t be surprised if the use of new technologies creates “dopamine resistance” in us, addiction, psychological ailments, and the like.

            Since our brains are plastic, it might be that the use of computers and cell phones, which often involve constant switching of activities, changes our mental circuits, and makes us less able to focus on long or demanding tasks. (Notice how all social networks are built around the rapid and successive switching of your focus of attention, e.g. infinite scrolling, and even YouTube has incorporated “stories” with an infinite sequence of short, irrelevant videos, that, of course, are chosen by the algorithm –or artificial intelligence already?—to seduce you.)

            When I was bedridden, I certainly abused these things. My head was exhausted just like my body, and it was a way to pass the time. I imagine several steps would be therapeutic here. The most important is working around the environment. Also, removal of triggers (as in addictions; inertia towards destructive behaviors is a thing to avoid), and discipline.

            Changing our approach to information is essential as well. Most people function this way: “I don’t know what to do, so I open my cell phone and see what’s there for me”. Instead, we should do like this: “I do know what I need, so that’s what I’ll do, in a straightforward way and without letting distractions get to me; in other words, I won’t wander around the cyberspace”.

            Meditation, “dopamine fasts”, and of course all the other steps that improve overall health, could be very helpful as well.

            At this point I can only pity the children. Being a great parent these days requires so much wisdom that does not seem to be within everyone’s reach. It seems we must shield them from so much evil, but remaining vigilant not to create an artificial bubble that may do them more harm.

            About the infection, certainly, it may not necessarily be in the brain. It is my understanding that microbiota has systemic effects and can certainly make someone feel miserably in many ways. I just had an interesting experience:

            I had recently reported that I had dysbiosis that was causing bloating and diarrhea for 3-4 months. It correlates well with irritability as well (not implying causation). I suspect it is fungal in origin because its onset coincided with fungal skin lesions. (The lesions disappeared in a few days by exposing the area to the sun.)

            Recently I adopted a low FODMAP diet, and discontinued coconut milk. Everything else was kept about the same – diet-wise as close as humanely possible considering the restrictions of the low FODMAP diet. (To help me take in enough calories, I included several ounces of pecans, which I don’t normally eat because I don’t like them very much and they are high in omega-6; also, the season for guavas started in mid-October, so I included many of those because fortunately they contain no FODMAP.)

            In about two days the symptoms associated with the dysbiosis disappeared. However, after a week or so I reintroduced coconut milk. I wanted to see how it affected. To notice clear symptoms, I ate half a liter per day during two days. The first day, no difference. The second day, my thinking was clearer. The third day, three bad things happened. For no apparent reason I felt great sadness and hopelessness that was not directed at anything. The brain fog came back. And the diarrhea appeared again.

            Here is my interpretation, recognizably pretentious and based on anecdotal experience: If I had a brain infection, perhaps the coconut fat ketones would have helped with some mental symptoms, inasmuch as the brain infection would not be able to steal this substrate. On the other hand, the bacterial activity would not cease as the rest of my diet is not ketogenic–the bacteria would still be breaking harbor, it’s just that I would notice less. Now, if I had a fungal dysbiosis in the gut, the infection would be able to feed on ketones. It would make sense that it returned when I restarted the coconut milk. Apart from this, I don’t know if the time lag would make sense.


          • In this modern world, we have chemicals and plastic, herbicides pesticides etc… these are called Endocrine-Disrupting Chemicals or EDCs, that disrupt the normal production of hormones. Regardless if your diet is great, sleep is perfect, exercise, these EDCs will just do that. So, first we start from nutritional deficiencies, including cholesterol which is so important for steroid hormones production, sleep and exercise, then supplementing or replacing as needed. We cannot achieve optimal health if hormones are not optimized/balanced

            Talking about head trauma and Pregnenolone, watch this video. with Dr Mark Gordon, he is the expert on head trauma and the subsequent decrease in neurosteroids, you have to really watch it, so you can start having an understanding about it. I have personally never seen this particular video, but I have seen many more of Dr. Gordon in the past


  12. Hi Paul, hi Eric (if you’re around),

    If you had time, what is your general insight about Mendelian randomization studies?

    For context:

    I have started to interpret the scientific evidence myself. I am still in diapers, but I see that everything fits well with the PHD advice.

    However, Mendelian randomization studies have been a stumbling block — it seems that one has to be pretty wise to assess their quality, since they rely on very specific genetic hypotheses and very heavy statistics. (I should mention that it doesn’t seem to be necessary to understand Mendelian studies to interpret nutrition, at least for now; as Eric once explained here, the old studies are often the best, and in any case, the evidence is often redundant before reaching clarity).

    They seem to be called a “natural alternative to randomized clinical trials”, but that seems overly optimistic on several counts. I know nothing about this, but a few arguments come to mind.

    The genome is a network of genes interacting with each other. It is hard to believe that a given gene would affect only one aspect of our biology. Moreover, if a relatively common gene has survived the process of natural selection, it is to be expected that it is because it has interacted favorably with other genes (and of course with the environment; except perhaps for a minority of selfish genes that may favor their own survival). So there must be important cofounding — but I don’t know how common or important that is: enough to make many studies “useless” or not? Maybe enough statistic power can beat the flaws, or not?

    One fact that caught my attention: most blogs and books I have ever read contain little or no mention of Mendelian randomization, including this blog. (At least explicitly; no results are found by searching “Mendelian randomization” or “Mendelian”.)

    Thank you.


  13. Hi Paul and everyone in the forum.

    Cooking and cooling starch overnight will diminish its carbohydrates content.
    How should we then count the carbohydrates content of cooled starch such as white rice and potatoes, especially for people involved in exercise who requires a certain amount more of carbohydrates?

  14. Postprandial triglycerides levels at 310 mg/dl normal on a PHD diet?? to note my blood glucose was at 89, A1c 5.2 tot cholesterol 270 and LDL 189, all postprandial a main meal

    • Hello Gianluca,

      Have you done more experiments?

      I don’t know enough data to put your numbers into perspective. (In a person on a standard diet, yes, these numbers levels be a bad indicator… but the standard diet contains about half as much fat as a typical implemmentation of the PHD).

      I am surprised that your postprandial glucose is the same as fasting levels; one would expect levels of 120-140.

      • I think I should try perhaps to check levels during fasting before breakfast, if Triglycerides comes back high again, then there is a problem

  15. hi paul, do you have any information on teff? it’s a ethiopian cereal grain but it seems different from the toxic ones you mentioned. anyways, i plan to use teff flour in baking. i really appreciate it if you can give me a estimate on its toxicity.

  16. Hi Paul,

    While doing your research for your book, particularly the research on what different cultures who haven’t/hadn’t yet been tainted by modern society eat, did you discover if these people ate multiple meals per day?

    I find myself wondering if humans are meant to eat only once per day, seeing that we would have had to hunt/gather food for each meal. Doing this multiple times per day seems energy and time expensive, so it seems logical that people would have eaten once per day.

    If so, I can’t help wondering if this is important to our health. Did you discover anything like this in your research? Or were you focused on the “what” and not the “how often”?

    Thanks for your time,

  17. Does anyone else here have a problem with Vit D supplementation? They make me tired and foggy. I have tried for years, all kinds: capsules, drops, sublingual, large doses, small doses, no additives, not in soy oil. I take MK 7 to help synergistically. Twice I took prescription from doctors because my levels were low. I know the prescription is D2, not D3, but I reacted the same and had to stop 3/4 of the way through, and 1/2 way through the second time. And my D levels still did not go up. I stopped for a long time, and just restarted this past month to try 1 more time. Same reaction: they wear me out and make my brain feel fuzzy. So, I reached out to the FB group and here to see if anyone has had the same or any reaction to D like I do, and I am open to options and opinions. Thank you for reading my long post.

    • If I remember correctly (I may not), I have heard Paul say “the reaction to vitamin D may be because you are depleted of it, so as soon as your immune system gets some, it goes to fight infections”.

      What are your current levels? If your doctor has prescribed it, they are probably very low (i.e. much lower than optimal).

      Do you have any disease? Or symptoms?

      You say you took vitamin D, yet your levels did not go up. How many IU did you take and for how long? Did you notice anything, apart from the tiredness and fogginess? There are two main possibilities for your vitamin D not going up after supplementing it: doctors often prescribe insufficient doses; or, there are conditions that show a resistance to supplementation. Example of the latter: http://perfecthealthdiet.com/2010/08/vitamin-d-dysregulation-in-chronic-infectious-diseases/

      Have you tried sunbathing (in the hours and seasons when UV rays are enough to generate vitamin D)? Do you get the same reaction from the sun?

      Certainly, what you describe suggest you are reacting to the vitamin D molecule itself. If you provide these data, we migh narrow down what is happening here.


      P.S. Hi everyone, long time since I had posted! I hope you are alright, Paul, Eric, Alexandra, Gianluca, etc.

      • Hector Thank you for your reply. I want you to know I am reading and studying the information, and I will respond again when I have assimilated it all. Especially the link you added from 2010. To say, I do not have any diseases or symptoms. And yes,my levels are low and have been for years, despite my supplementing and using the MD’s prescriptions, which I know are D2, and I am not fond of their medication. Still did not help. I never took more than 5000 IUs a day. For months. I am not willing to self dose any higher. I will post to you again after I study the link. Many thanks. Do you think Paul might have some input here? I would love to hear his opinion as to why I react to D3 supplements.

        • Some heuristics I think Paul would agree with:

          – On this blog we believe in collaborating with the body: that is, if the body wants to stay at certain vitamin D levels, perhaps it has a reason to do so.*

          – Often one gets worse before one gets better.

          – Often the symptoms that infections produce, at least in the short term, come not from the infection itself but from the activity of the immune system.

          Of course, all of this requires nuance.

          * For example: if your vitamin D does not go up, it is hard to know whether it is because of a regulatory mechanism in your body (i.e., your body wants to stay there), or an external factor such as an infection that wastes vitamin D, or a defect that does need to be circumvented, e.g., an infection playing with your biochemistry, or mutations on the pertinent gens.

          On this blog, a good way to start is to look for any comments that mention vitamin D as well as the 10 articles in the “Vitamin D” category. Search for other people’s experiences on the Internet, and relevant articles in Pubmed. Explore what vitamin D interacts with, and whether it may be a cofactor that is involved. Other tests might give clues, such as your 1,25D levels or your PTH, but only if you know how to put them in context.

          However, often problems require a pragmatic approach, because in biology things are difficult, or else we just don’t know enough.

          So I suggest that you make decisions with a positive benefit/risk range that could narrow the possibilities. Here two examples:

          – I’d try the D3 form, rather than D2. It might be relevant, as AFAIK that is not an homologous form. Besides that, D3 is more effective.

          – You could try to raise your vitamin D levels with sun or UV lamps (with care, of course). And then check: a) do the blood levels go up? and b) do you experience the same side effects?

          Vitamin D is very important to health. And it would be quite unlikely if it really hurt you. (It could happen e.g. an infection could explode the vitamin D paths somewhat, but it must be rare. And any harm would have to be balanced against the other benefits of vitamin D.) So I would definitely keep trying to solve this mystery.

          If you get more clues, I’m sure others, including Paul, would chime in if they have something relevant to say. Good luck, come back, and have courage!


        • By the way, does your diet provide enough magnesium, vitamin A, zinc, phosphorus?

          Is your diet either too low or too high in calcium?

          While taking the vitamin D, were you pregnant?

          Have you tried to take vitamin D without vitamin K2, just to discard the vit K2 being a problem?

          Another possible experiment is to take vitamin D from a natural concentrated source (not a supplement), such as cod liver. (Don’t buy it in capsules because it will be rancid; look for cans).

          (As for the D2 and D3 thing I said, sorry, then I remembered you had also tried D3.)

          Do you take the vitamin D in the morning? Not in the night, as it signals daytime.

  18. Hi,

    I have been suffering from dysbiosis for months. My immune system is depressed due to a medical condition, and this may be contributing to the perseverance of the problem (even though I do PHD and tried so many things).

    Well, for two days I have been taking a yeast called Saccharomyces boulardii, 500 mg of the commercial preparation UltraLevura. Only two days, but this has already greatly improved my digestive symptoms.

    Interestingly, it is also giving me major headaches and high body temperature.

    Could this be due to an immune reaction to the probiotic itself, or a Herxheimer type reaction?

    (After a look at the mechanisms of action of S. boulardii, e.g. https://pubmed.ncbi.nlm.nih.gov/31143070/, the Herxheimer-like reaction seems less likely. But this is just my guess. It does not seem to abruptly destroy other microbes; it simply makes life more difficult for them. If anything, it should decrease the amount of endotoxins if it can actually degrade toxins from other microbes or decrease their adherence, improve intestinal permeability, etc.)

    Before this experience, I was very reluctant to try this probiotic, mainly because a) if my dysbiosis were fungal, incorporating another type of yeast might do more harm than good (as long as yeasts may need the same conditions to thrive, the triumph of one improves the field for others); and b) what is one microbe versus the hundreds we have in the gut? I had already tried several batches of homemade fermented vegetables, and also the VSL#3 probiotic, and my experience was always negative or at best neutral.

  19. Paul, I am seriously underweight and I recall (in the intro to your book, I believe) that you had a period with nutritional deficiences. I am at 80 lbs, 5’5″ and am working on a new hypothesis that I have Pellagra. This hypothesis came from a profile of the disease which matches my problems pretty well. My increasingly restricted diet, childhood use of antibiotics to treat acne, mid-life overdose of antibiotics and antifungals gave me some major contributing factors. At this time, I think I have become anorexic – deficient in lots of things – and have serious gut problems and severe osteoporosis. You mention in your book that a carefully crafted diet is especially important when the calories are lower. I think an especially carefully crafted diet will be important to me, also. Can you suggest a diet tracker that provides feedback on the vitamins and minerals I will need? Also can you suggest which I may need to increase because of deficiency? I preach your diet all the time, but am not using it as I should, so hope you have some thoughts to guide me. Many thanks to you and all the helpers.

    • Hi Sally,

      I can share with you my experience, as I was anorexic as well. I suffered from severe Crohn’s disease which was refractary to treatment. My gut was destroyed; eating produced pain; I had no appetite; and could not absorb whatever I ate. (Inflammation can powerfully suppress hunger; for example, it is one of the effects of elevated TNF alpha). Besides that, some foods were able to worsen my condition instantaneously and prodigiously (e.g. dairy) so even in these cases a very restricted diet was needed–which must not be tagged as orthorexia or anorexia nervosa. The situation was difficult. As I kept getting worse, I had to resort to enteral nutrition. Even there, what I learned with the Perfect Health Diet was helpful: e.g., I could chose a formula with no fructose and no excessive omega-6. But even that wasn’t enough because I couldn’t eat enough due to the poor appetite. I asked to be admitted and was put on parenteral nutrition (peripheral intravenous), corticosteroids, and other medications. By halting the inflammatory cascade and reducing inflammation in the intestines, I recovered appetite and the ability to absorb some calories. Henceforth I was able to start getting better. Nowadays I’m still resolving chronic health issues, but I’m infinitely better.

      I imagine that you are already under medical treatment, but if not, it is worth saying that anyone under these circumstances must not be afraid to get a doctor who is willing to help. In complex health cases, we are sometimes tempted to look for excessive explanations and devise complex plans of attack (which may certainly be needed, together with trial and error, so solve chronic and unexplained health problems). However, we must not let the perfect be the enemy of the good. A mediocre treatment given early may be better than a perfect treatment given late.

      Oftentimes you don’t need the best doctor, but the one who is willing to help. While it’s true that doctors don’t always get it right, the sicker you are, the lower the risk of iatrogenesis. This is to say: any treatment a doctor might put you on is likely to do more good than harm, as the potential for getting better is greater than the potential for getting worse. And if your body has fallen into a spiral of illness (e.g. you need calories to beat a condition, but that same condition strongly prevents you to get calories, while over time you can only get worse) it’s often impossible to get out without the help of doctors, which may need aggressive treatment.

      With regard to the diet trackers: I’ve tried several diet trackers, and the best ones were Cron-o-meter, then Fitday. Eric wrote about how to set Cron-o-meter up to suit the nutrient goals posed by the Perfect Health Diet (you will notice some of what he said about carbohydrate no longer applies today, as Cron-o-meter changed that bit): http://perfecthealthdiet.com/the-diet/comment-page-27/#comment-1766291

      I imagine your idea is to see what nutrients you are getting with the diet you are following, to see which ones you need to supplement, is that it?

      Doing so, do keep in mind that calories are the most important nutrient a starving body needs.(Even if we had all the micronutrients we could possibly need, without energy the cell cannot use them–without sufficient energy, only the sequentially most essential functions are carried out. Other functions that are extremely important but not strictly necessary for immediate survival are not performed, e.g. sexuality, maintenance of tissues and bones, or the functioning of the immune system, leaving us sold out to the progression of any disease.)

      Apart from that, you might find this series of posts on bowel disease interesting; see this post http://perfecthealthdiet.com/2010/07/bowel-disease-part-iii-healing-through-nutrition/ and the rest in the series.


  20. Paul,
    Is there a link between High Blood Pressure, Bladder Infection and Sinusitis. I seem to be getting all of it together. Any recommendations?

    Thank You

    • Hi Tessy,

      There certainly can be. Bladder infections and sinusitis are both caused by infections of the epithelial surfaces in the urinary tract and sinuses, and they might be the same infection / same pathogen just in two locations.

      The connection between infections and hypertension is more complex but there can certainly be causal connections. For example, it’s known that TLR4 activation (toll-like receptor 4, a pathogen detecting receptor) is a contributing cause of hypertension, see for example https://pubmed.ncbi.nlm.nih.gov/28330785/. You can read about TLR4 here: https://en.wikipedia.org/wiki/Toll-like_receptor_4. It is mainly activated by lipopolysaccharides (LPS) from Gram negative bacteria. These can be either a systemic infection, or an infection of the digestive tract / small intestine in which cell wall components including LPS of dead bacteria from the intestine are carried into the body along with food and activate TLR4 once inside. This will often lead to both hypothyroidism and high blood pressure.

      So a bacterial infection of the sinuses, small intestine / digestive tract, and bladders / urinary tract would be a single explanation that explains all three.

      Make sure you have good vitamin A/D/K2 status to fight this!

      Best, Paul

  21. Hi Paul,

    Can the perfect health diet can be used if one has chronic kidney disease?

    • Hi Steven,

      Certainly. The idea of PHD is to provide the optimal amount of each nutrient, no more and no less. This also minimizes work by the kidneys. … The one alteration I would make is to minimize supplementation and try to get nutrients from food.

      Best, Paul

  22. Dear Paul,

    Can malnutrition or a lack of certain micronutrients or an excess of certain micronutrients cause gynecomastia or a hormonal disorder in men?

    Can a disrupted microbiome or gut disease cause hormonal imbalances in men?

    Best regards


  23. Dear Paul,

    do you have any tips on how you can stop or counteract hair loss with your diet?
    Which micronutrients play a crucial role here?
    How can I promote my hair health?

    Best regards


    • Hi Marius,

      Hair loss is mostly an autoimmune or inflammatory issue. You can keep down dietary omega-6 fats; protect against oxidative stress with zinc, copper, selenium, vitamin E as mixed tocopherols/tocotrienols, glycine, taurine; protect against infections with vitamins A and D; circadian rhythm entrainment; correct any hypothyroidism or small intestinal / gut microbial overgrowth.

      But, autoimmune conditions are difficult to reverse.

      Best, Paul

  24. Hello Paul,

    ater reading your posts and comments, I have made an assumption about my health problems and I would be incredibly grateful if you could tell me briefly whether my thoughts are completely absurd or not.

    My guess in brief: I suspect that I have developed a leaky gut due to years of poor nutrition.
    I consumed large amounts of pasta and baked goods and other unhealthy foods. Due to my leaky gut, I have developed numerous food allergies and possibly histamine intolerance or lactose intolerance.
    As soon as I eat fiber-rich foods or certain dietary supplements that increase my bacterial population in the intestines, in combination with purified fats (clarified butter, butter, coconut oil, olive oil, etc.), severe inflammation occurs in my body due to acute endotoxemia and other toxins in my body be transported.

    To prevent my problems from progressing, my approach would now be to heal the root cause of all my problems, namely my leaky gut, and avoid all purified oils and supplements during this time.

    A quick question: Can I continue to consume cream, cheese and fatty meats during this time to supply my body with saturated fats, or can these whole foods also cause endotoxemia?

    Thank you for your time.

    Best regards


    • Dear Paul,

      I also read an interesting article on endotoxemia that makes me think a bit:


      What do you think of the results mentioned in particular in point 5?

      Best regards


      • For example, the article states that a diet enriched with 20% refined palm oil can lead to more active and pro-inflammatory transport of LPS to target tissues via high plasma concentration of LBP and lower concentration of sCD14. Conversely, a diet enriched with 20% rapeseed oil results in lower inflammation in both the circulatory system and adipose tissue, particularly through an increase in plasma sCD14 concentrations (Laugerette et al., 2012).

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