Higher Carb Dieting: Pros and Cons

Last week’s post (Is It Good to Eat Sugar?, Jan 25, 2012) addressed what I see as the most problematic part of the thought of the health writer Ray Peat – his support for sugar consumption.

Apart from this difference, “an extreme amount of overlap is evident,” Danny Roddy notes, in our views and Peat’s. Both perspectives oppose omega-6 fats, support saturated fats, favor eating sufficient carbs to normalize metabolism, support eating nourishing foods like bone broth, and oppose eating toxic foods like wheat.

If there is another difference between our ideas and Peat’s, it’s that “Peat-atarians” often eat more carbs. Danny puts it:

Paul and Peat have similar recommendations for carbohydrate consumption. Paul’s recommendations hover around 150 grams while Peat usually recommends 180-250 grams, but he himself eats closer to ~400 grams.

So I thought it might be worth looking at the issue of overall carb consumption.

Carbs for Hypothyroidism

In Is There a Perfect Human Diet? (Jan 18, 2012) we noted that diseases can change the optimal diet. In some diseases it’s better to lower carb consumption, but in others it’s better to increase carb consumption. The example we gave is hepatitis; hepatitis B and C viruses can exploit the process of gluconeogenesis to promote their own replication, so high-carb diets which avoid gluconeogenesis tend to slow down disease progression.

Another disorder that might benefit from more carb consumption is hypothyroidism. A number of people with hypothyroidism have benefited from Peat-style carb consumption. Here is ET commenting on last week’s post:

As someone following the PHD with a good dash of Peat, I really enjoy this post and the comments. Thank you Paul….

Paul says that “I’m not persuaded that it’s a desirable thing to keep liver glycogen filled at all times, but for some health conditions it may be good to tend that way, like hypothyroidism.” Well, according to Chris Kresser, 13 of the top 50 selling US drugs are either directly or indirectly related to hypothyroidism. If going by either the low body temperature/low pulse diagnostic, and/or some kind of pattern on the serum tests (Anti-TG, TPO, TSH, free T-3, free T4, total T3, total T4), we are talking a significant proportion of the population, especially women, being hypothyroid in some form….

Many with low T3 have a conversion problem from T4 in the liver (80% of T3 is converted from T4 in the liver and kidneys – only a small portion is coming from the thyroid gland).

Is it a good idea to NOT try to fill the liver glycogen in such a pattern? For those who have lived with the consequences of low T3 (adrenaline rush, waking up in the middle of the night, fatigue, tendency to orange-yellowish color i the face etc.), and had improvements on a more Peat like diet, I do not think so.

The way to fill liver glycogen, of course, is by eating more carbs.

I’ve previously noted that increased carb consumption upregulates the levels of T3 thyroid hormone (Carbohydrates and the Thyroid, Aug 24, 2011):

T3, the most active thyroid hormone, has a strong effect on glucose utilization. T3 stimulates glucose transport into cells, and transport is the limiting factor in glucose utilization in many cell types. In hyperthyroidism, a condition of too much T3, there are very high levels of glucose utilization. Administration of T3 causes elevated rates of glycolysis regardless of insulin levels.

The body can reduce T3 levels by converting T4 into an inactive form called reverse T3 (rT3) rather than active T3. High rT3 levels with low T3 levels lead to reduced glucose transport into cells and reduced glucose utilization throughout the body.

This means that eating more carbs raises T3 levels, and eating fewer carbs lowers T3 levels.

For a hypothyroid person, then, eating more carbs is an alternative tactic for increasing thyroid hormone activity. It may provide symptomatic relief similar to that achieved by supplementing thyroid hormone directly.

Perhaps the two are complementary tactics that should be done together. Taking thyroid hormone pills will increase glucose utilization, creating a need to eat more carbs. A mix of the two tactics may be optimal.

UPDATE: Mario points out that most cases of hypothyroidism in advanced countries are due to Hashimoto’s, an autoimmune disease probably triggered by infections or gut dysbiosis, and eating more carbs will tend to flare any gut dysbiosis and thus aggravate the thyroiditis. Meanwhile, supplemental thyroid hormone tends to reduce antibody activity.

Carbs for Mood

Another interesting comment came from Jim Jozwiak:

Paul, this discussion gets to the crux of what I do not understand about the Perfect Health Diet. You are speaking as if refilling liver glycogen is a good thing, and it undoubtedly is, because mood is so much better when there is sufficient liver glycogen because then the brain is confident of its power supply. Also, you acknowledge that safe starch would eventually replenish liver glycogen after muscle glycogen is topped off. So why not eat enough starch to replenish liver glycogen? It is not so difficult to figure out how much that would be. Have some sugar, feel what replenished liver glycogen is like, then titrate safe starch gradually meal-by-meal to get the same effect. When I do it, and I am not an athlete, I get 260 grams of non-fiber carb per day, which is considerably more than you usually recommend. Have you tried this experiment and found the result unsatisfactory in some way?

Jim has experimented to find the amount of carbs that optimize his mood, and found it to be 260 g (1040 calories). On a 2400 calorie diet, typical for men, this would be 43% carbs.

If Peat typically recommends 180 to 250 g carbs, as Danny says, then on a 2000 calorie reference diet that would be 36% to 50% carbs.

Those numbers are strikingly similar to another statistic: The amount of carbs people actually eat in every country of the world.

Here is a scatter plot of carb consumption vs per capita income by country. Dietary data comes from the FAO, income is represented by GDP per capita from the IMF:

At low incomes people eat mainly carbs, because the agricultural staples like wheat, rice, corn, and sorghum provide the cheapest calories.

As incomes rise, carb consumption falls, but it seems to approach an asymptote slightly below 50% carbs. The lowest carb consumption was France at 45%, followed by Spain, Australia, Samoa, Switzerland, Iceland, Italy, Austria, Belgium, and Netherlands.

We can guess that if money were no object, and people could eat whatever they liked, most people would select a carb intake between 40% and 50%.

This is precisely the range which Jim found optimized his mood.

The Longevity vs Fertility and Athleticism Trade-off

I won’t enumerate studies here, but animal studies indicate that higher carb and protein intakes promote fertility and athleticism, while restriction of carbohydrate and protein promotes longevity.

In our book, we calculate the daily glucose requirements of the human body at around 600 to 800 calories, or 30% to 40% of energy on a 2000-calorie diet.

So a 30-40% carb diet is a neutral diet, which probably places minimal stress on the body.

A 40-50% diet is a carb-overfed diet, which probably promotes fertility and athleticism.

A 20-30% diet is a mildly carb-restricted diet, which probably promotes longevity.

Do we see diminished longevity with higher carb consumption in human epidemiological data? I think so.

It’s useful to compare European countries, since they are genetically and culturally similar. There is a correlation between carbohydrate intake and longevity. Here is a list of life expectancy among 46 European countries. Neglecting little countries like Monaco, San Marino, and Andorra, that are not in my carb database, the countries with the longest life expectancy are also the ones with the lowest carb consumption: Italy first, France second, Spain third, Switzerland fourth, and Iceland sixth are all countries with carb intake below 50%. Sweden, at 50.8% carbs, placed fifth in longevity.

Did Evolution Hardwire a Preference for Carbs?

We know that the brain has an innate food reward system which tries to get people to eat a certain diet. What carbohydrate intake is it likely to select for?

Experiments on the food preferences of insects and rodents give us clues. The paper “Macronutrient balance and lifespan,” by Simpson and Raubenheimer, cited some time ago by Dennis Mangan, summarizes evidence from animals for the influence of macronutrients on lifespan. A good example is the fruit fly; protein has the dominant effect on lifespan, with low protein favoring longevity and high protein favoring fertility. The flies eat so as to maximize fertility:

The response surface for lifetime egg production peaked at a higher protein content than supported maximal lifespan (1:4 P:C, Figure 1A). This demonstrates that the flies could not maximize both lifespan and egg production rate on a single diet, and raises the interesting question of what the flies themselves prioritized – extending lifespan or maximizing lifetime egg production. Lee et al. [3] answered this by offering one of 9 complementary food choices in the form of separate yeast and sugar solutions differing in concentration. The flies mixed a diet such that they converged upon a nutrient intake trajectory of 1:4 P:C, thereby maximizing lifetime egg production and paying the price of a diminished lifespan.

This seems to be the evolutionary preference in mammals as well as flies. When unlimited food is available, animals tend to overfeed slightly on carb and protein, sacrificing lifespan for increased fertility and athleticism.

Jim reported improved mood on a 43% carb diet. Is it due to the filling of liver glycogen raising metabolism? Due to a sensation of enhanced fertility, libido, and athleticism? Or simply due to greater satisfaction of the brain’s reward system?

Yet another factor may also be involved.

Might Stress Be Mistaken for Enhanced Energy?

Peat favors sucrose as a carb source, which is why Danny Roddy recommended orange juice and Travis Culp soda. I argued in last week’s post that it would be better to eat a starchier diet so that the carb breakdown would be at least 70% glucose, less than 30% fructose and galactose.

Eating a higher-carb diet fills up liver glycogen, removing the most rapid fructose disposal pathway. This makes a high-carb sucrose-based diet rather stressful for the body; it has to dispose of fructose rapidly to avoid toxicity, but has limited ability to do so.

We can see the stressfulness of sucrose by its effects on the “fight-or-flight” stress hormones adrenaline (epinephrine) and noradrenaline (norepinephrine). Here is a study that fed high-fat, high-starch, and high-sucrose diets for 14 days to healthy non-obese subjects, and measured the hormonal response [1; full text]. This paper was discussed by the blog Proline (hat tip: Vladimir Heiskanen). The results:

On high-fat and high-starch diets, adrenaline and noradrenaline levels are low; they are consistently elevated — almost doubled — on the high-sucrose diet.

This makes sense; as Wikipedia notes,

epinephrine and norepinephrine are stress hormones that underly the fight-or-flight response; they increase heart rate, trigger the release of glucose from energy stores, and increase blood flow to skeletal muscle.

These hormones trigger the release of glucose from liver glycogen, thus freeing up room for fructose disposal.

Note that this result contradicts an assertion by Danny Roddy:

I consider the ability to refill glycogen (minimizing adrenaline & cortisol release) to be an important factor in health.

Refilling glycogen is not the same thing as minimizing adrenaline release. The requirement to dispose of fructose may trigger adrenaline release.

The reason I bring this up is not to renew the starch vs sugar discussion; but rather to ask if this “fight-or-flight” response to sugar consumption may not be partially responsible for the perceived mood and energy improvements on a Peat-style diet.

Indeed, one of the peculiar aspects of Ray Peat’s health advice is his recommendation to increase pulse rates well above normal levels. In his article on hypothyroidism, Peat states:

Healthy and intelligent groups of people have been found to have an average resting pulse rate of 85/minute, while less healthy groups average close to 70/minute.

I would have thought 60 beats per minute was normal, and when I was more athletic my pulse was typically 48 beats per minute.

One of the effects of adrenaline and noradrenaline is to speed up the pulse rate. If Peat really does eat 400 g of carbs per day, predominantly from sucrose, then he may be achieving his high pulse rate from an “adrenaline rush” that helps dispose of an excess of fructose.

If, indeed, this is a source of improved sense of well-being on Peat-style diets, it may be a double-edged sword. Chronic stimulation of the “fight-or-flight” hormones to aid in fructose disposal may have long-run negative consequences.

UPDATE: I’m reminded of this video, showing the adrenaline-promoting effects of sucrose consumption:

Starch would not have had the same effect, and would surely be healthier in the long run.


It is possible that higher carb intake may increase thyroid hormone levels, fertility, and athleticism, and enhance mood in some people. These gains do not come without cost. Notably, they probably involve a sacrifice of longevity.

If the benefits of higher carb intake are sought, it is best to achieve them by eating starches primarily, not sugar.


In our book, we recommend a slightly low-carb diet of 20-30% of calories. If we were re-writing the book now, we would probably be a bit less specific about what carb intake is best. Rather, we would say that a carb intake around 30-40% is neutral and fully meets the body’s actual glucose needs; and discuss the pros and cons of deviating from this neutral carb intake in either direction.

For most people, I believe a slightly carb-restricted intake of 20-30% of calories is optimal. Most people are not currently seeking to have children or engaging in athletic competition. There is good reason to believe that mild carb restriction maximizes lifespan, and most people desire long life. As we’ve noted, supercentenarians generally eat low-carb, high-fat diets.

But the spirit of our book is to educate, and let everyone design the diet that is best for them. And there is room for difference of opinion about the optimal carb intake.


[1] Raben A et al. Replacement of dietary fat by sucrose or starch: effects on 14 d ad libitum energy intake, energy expenditure and body weight in formerly obese and never-obese subjects. Int J Obes Relat Metab Disord. 1997 Oct;21(10):846-59. http://pmid.us/9347402. Full text: http://www.nature.com/ijo/journal/v21/n10/pdf/0800494a.pdf.

Leave a comment ?


  1. Thought-provoking and informative as always.

    Sometimes I wish I had my own team of scientists to study the crazy stuff I want to study, like if low inflammation and good nutrition makes the body more resilient to the effects of epinephrine and less likely to express “adrenal resistance” like it does with insulin. I can see where Peat and his readers are coming from with the love of sugar, it can have some psychological benefits. During a painful procedure it reduces the time that a baby cries, for example http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004494/

    And so for those who get stabbed frequently due to shady dealings, sucrose might be the optimal choice. Planning on getting in a fist fight? Sucrose is your friend. It can be drug-like, and drug-like can be a good thing in some situations, but possibly have side-effects with chronic use. So I don’t completely disagree with the idea of using sucrose as a supplement. The Peatatarians suggest that a good diet makes sucrose less harmful, and this is definitely true with regards to the metabolic syndrome. I don’t know about that, but I’m not ruling it out. But as a diet author you’re certainly justified in saying to cut out most of the refined sugar.

    The data from Europe is interesting and I have noticed some of the same trends. A good amount of dietary fat is associated with longevity, but there are confounding factors. Less carbohydrate can mean less grains, for example. There is also the issue of antioxidant status. Better antioxidant status like with the Kitavans might mitigate the oxidative nature of sugars in the mitochondria. There is that experiment with c elegans that suggested that glucose reduced its lifespan, but it probably doesn’t have the same adaptation as us. When I get motivated I’ll have to look into this further with mammalian animal studies. Maybe as an adjunct to learning more about genetics. It will be fun!

    I know, I’m an insufferable skeptic. That research about the booze opened me up to the concept of the mitigating factor and now I’m ruined. I can’t believe anything anymore except that glutathione makes mice boozing machines.

    (PS to all readers. What does Ray Peat think about alcohol? Links would be appreciated if possible)


  2. Paul,

    Thanks for the interesting post. In the last year I increased my carb consumption to taste – probably around 250 grams per day. I feel like I have more energy now and my mood is better. And my cholesterol levels, which went way up after starting a lowish carb high fat “paleo” a few years ago, went back down again. The doc was amazed.

    • Same here Todd..my cholesterol in Jan 2013 was 14.2 mmol/L (HDL 1.70 /LDL 12.14/ TRIGS 0.8)after a year of a very low carb diet, lots of raw cream, meat, vegetables, all organic good grass fed, etc.
      I came across Peat/ Roddy, etc and implemented eating more fruit,upped drinking more raw milk (and skipped the cream for now). Still eat some meat, low-fat fish, prawns ..cholesterol re-test in late August this year is total 6.2 (trigs 0.8/ HDL 1.57/ LDL 4.27). To add to that, I feel much better ,and have much more strength and vitality .
      My doctor ,too, was amazed.

  3. @Stabby

    You said “During a painful procedure it reduces the time that a baby cries, for example http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004494/

    But some other papers seem to show that glucose might be as good as sucrose: http://www.functionalps.com/blog/2012/02/02/sucrose-infant-pain-reliever/

    “After the heel prick of both the sucrose and glucose groups the duration of first cry and total crying time was significantly reduced (P = 0.005 and P = 0.007).”

    “Even if the trend of the cardiac rates did not reach statistic significance, glucose solution 33 and 50% proved to be the most effective in reducing pain response.” (there were 2 sucrose groups too but glucose was better than sucrose)

  4. Higher Carb Dieting: Pros and Cons « Thor Falk's Reading List - pingback on February 3, 2012 at 3:16 am
  5. Thank you for your blog. This is just another fantastic & rational post. Your humble writing style is incredibly refreshing. Now during your spare time, could you just cure autism 😉

  6. As Gary Taubes likes to say, it’s good to look for counterexamples when evaluating theories. Here’s one for the idea that low carb diets work against athleticism:


    Peter eats a very low carb ketogenic diet. And what you see here is only his formal workout, not the hours of incredible athletic activity he does each week in addition.

  7. Paul, it would be great if you could comment on carb consumption for those with any kind of gut dysbiosis (SIBO, IBD) or more serious conditions (UC, crohns, etc.) as well as diets like SCD and GAPS…

    Where would people like that fit into PHD’s recommendations? For example, many people are healed and/or go into remission from serious diagnosis on the SCD, which eliminates all starches (as well as other carbs), yet you recommend starches. Are your recommendations only for “healthy” people?


  8. Hi Stabby,

    Looks like Valtsu has my back on the glucose vs sucrose front.

    I’m in the same boat with you, I’ve been planning to look into longevity studies when I get time … for the last year!

    Hi Todd,

    Yes, it looks like 250 g is a reasonable maximum where benefits end. Trade-offs below that.

    Thanks, Valtsu!

    Hi Jim,

    I do hope that more parents of autistic kids will try our diet & approach and see if it helps. I think it’s likely to help. Maybe in time we can track down causes and cures.

    Hi Bill,

    You can have outstanding athleticism, by ordinary standards, on a low-carb and ketogenic diet. The question is, will you recover quickly enough and be able to train long and hard enough to compete with the elite athletes eating more carbs? If you want an Olympic gold medal, I wouldn’t recommend ketogenic dieting.

    Hi Sean,

    In general gut dysbiosis benefits from low-carb dieting, as in SCD and GAPS, because gut pathogens feed on carbs.

    Like SCD and GAPS, we recommend eliminating problematic foods while actively re-shaping the gut flora. However, we do not automatically assume that starches are the primary problem (though they are commonly a problem). Fructose can be a problem too, or FODMAPs, or fiber, or even protein. So it takes some experimentation to figure out the optimal diet that both nourishes you and deprives the pathogens of their preferred foods.

    In severe gut dysbioses, it may be necessary to get carbs in pre-digested forms like dextrose which are easily absorbed in the small intestine.

    You might want to look at our Bowel Disease category for more thoughts: http://perfecthealthdiet.com/?cat=47.

    Best, Paul

  9. Great post, Paul. It makes me think again about the “listen to your body” idea …

    Feeling bad – makes sense to make changes to feel better, that’s easier.

    Feeling good – may be short term and there could be longer term consequences. If mostly feeling good, how’s a person know they’re possibly doing harm … maybe rely on lab work results …


  10. From what I’ve read via Dr. Peat’s newsletters,he prefers his “sugars” to come from 1. tropical fruit, 2. honey(if not an allergen), 3.sucrose. He usually will rec. sucrose for a “short term fix” to help the liver to convert t4 to t3 conversion. In an interview he gave he said that half of cal. came from fruit, not sucrose.He has written that sat. fat and fructose can help block aclohol damage on the liver(sorry I don’t have a reference),I believe Chris Masterjohn has also written on this topic in Wise Traditions from last yr. These are my interpitations on his work, take that for what it’s worth. Paul, keep up the good work.

  11. Paul,

    Regarding hypothyroidism, Danny wrote, about PHD:

    “May not be an optimal diet to treat hypothyroidism/chronic stress (inefficient glycogen storage, elevated free fatty acids).”

    And, you wrote:

    “For a hypothyroid person, then, eating more carbs is an alternative tactic for increasing thyroid hormone activity. It may provide symptomatic relief similar to that achieved by supplementing thyroid hormone directly.”

    Let’s make no mistakes and not forget: hypothyroidism, in developed countries, is mostly due to autoimmune thyroiditis (Hashimoto’s), probably caused by disbiosis and molecular mimicry, that leads to thyroid destruction.

    So, if a person have Hashimoto’s, a diet high in carbs that increases thyroid hormone activity could have some great short term benefits, but could also led to an autoimmune overreaction and an accelerated destruction of the thyroid.

    Finally, since levothyroxine treatment, in patients with hypothyroidism due to Hashimoto’s, results in a markedly reduced antibody activity (pubmed 18631004, 11327616), I think it may not be advisable to replace the supplemental thyroid hormone for a high carb diet. At least, not while the real causes of the Hashimoto’s are addressed.


  12. Hi Kevin,

    I don’t believe that fructose blocks alcohol damage in the liver. Saturated fat does, if it is displacing polyunsaturated fat.

    Hi Mario,

    That’s a great point. Adding carbs will aggravate a gut dysbiosis, and gut dysbiosis is a likely cause of Hashimoto’s.

    Thanks for the papers on levothyroxine and antibody activity. Links: http://pmid.us/18631004; http://pmid.us/11327616.

    Best, Paul

  13. Hi Paul:
    What should the conversion from T4 to T3 be? Is something lost in the process whereby it is less than 1:1 but still ok? For example being in the top qtr of the lab range for T4, but bottom qtr of normal range. Is this indicative of an issue in the absence of Hashimoto? Could it be genetics, or due to environmental toxins?

    A higher carb diet while it may show wonderful cholesterol results on a simple blood test may be wholly misleading. LDL particles could be totally out of concordance with LDL blood measurement. I know when i was on a highish carb diet my LDL was 72, but my LDL particle count was 1,800. Total discordance. Lower the carbs, and particle count falls.
    Also, being of European ancesty, I think i do better with potatoes than for example rice. Were I of Asian ancestry i might think the opposite.

    Excellent thought provoking post. I will stick with PHD, or even tighter carb control based on health and genetic, and family disease history.

  14. Hi Steve,

    It’s impossible to interpret a T3 level in isolation. Low T3 and high T4 could indicate a low carb diet, it could indicate a selenium deficiency, it could indicate nothing because T3 levels fluctuate through the day in response to meals and activity and circadian rhythms.

    If you have symptoms of hypothyroidism then that would tell us it was something to be concerned about.

  15. another gold star for the “all bodies are different” concept…. i just finished the first 30 days of Kresser’s Personal Paleo Code, and my mood has been spectacular — the only things i haven’t consumed that are usual with me are dairy, alcohol, stevia and splenda, and a small amount of rice. i ate more fruit over the month than is usual for me, but less than a piece per day. i feel fabulous.

    my body guides me toward a very low carb intake — i gained fat at the low end of carb recommendations on the PHD if i ate them early in the day! …and i’ve been hypothyroid all my life (56 years).

  16. Thanks Paul:
    Don’t have to my knowledge any symptoms of hypothyroidism. Was just asking what might the conversion be; is it 1:1 or is something lost.

  17. Hi Steve,

    No, T4 is not all converted to T3, it can be converted to rT3, it depends on where the iodine is removed from the T4 (a 4-iodine molecule).

    There’s no specific T4:T3 ratio that we can declare optimal. Low T3 relative to T4 is associated with hypothyroidism, metabolic syndrome (eg http://www.ncbi.nlm.nih.gov/pubmed/22229843) and other health problems, but it also occurs on low carb as a glucose conservation measure, and there’s no reason to think that’s pathological.

  18. “The example we gave is hepatitis; hepatitis B and C viruses can exploit the process of gluconeogenesis to promote their own replication, so high-carb diets which avoid gluconeogenesis tend to slow down disease progression.”

    I curious about this statement. It seems this works both ways:

    “Hepatitis C Virus Infection Promotes Hepatic Gluconeogenesis…”


    “The plasma glucose response to glucagon was 1/3 that of normal controls, and was not improved by a high-carbohydrate diet…. Acute viral hepatitis results in serious impairment in hepatic glycogen synthesis and gluconeogenesis and frequently gives rise to fasting hypoglycemia….”


    Why do you think the virus is exploiting the process and it should be minimized?

  19. spitballing:

    what the frontrunners of the paleo-ish (real food) movement seem to be reaching is a consensus with certain “bodybuilding” concepts. cycling higher carbs, and then going into ketosis, repeat. being “metabolically flexible” as it were. intermittent fasting also belongs in this category, coaxing the body into using fuel differently, breaking up “fuel-habits”.

    something i’m noticing though is being metabolically flexible seems to require 1- a healthy thyroid that can go from neutral to hyper and back again quickly and easily, and 2 – the correct gut environment to optimize immune function and nutrient absorption.

    one of peat’s big claims is that taking the thyroid from hypo into a relative hyper state, because anything better than hypo IS hyper comparatively, will help fix and optimize gut dysbiosis. so for any of us who are hypothyroid, a certain amount of time in the land of hyper might speed up healing in general, similar to how the body uses a fever to fight an infection, or how sunbathing, bathing in hot springs or being in saunas is contextually therapeutic – it is a all a form of heat therapy, whether exogenous or not.

    if humans are really sun-worshippers, then perhaps there is a physiological reason for that. perhaps intelligently & cyclically increasing our internal temperature is a big key to maintaining or regaining health.

  20. To answer my own question:

    “Physiologically, we show that a short-term fast that turns on the gluconeogenic program robustly induces HBV gene expression in vivo.”


    Yet GNG seems negatively impacted in the long-term. Might this be defensive?

  21. Hi Paul,

    I have a few points to make about some of your sections.

    First, the comment about Hep C is debatable: George Henderson makes a strong case for high fat diets in his blog “The High-fat Hep C Diet Blog.”

    Regarding hypothyroidism and carbs, I thought you made a good case in your series that it was difficult to tease out any precise effects of carbs or fat per se on thyroid levels. People have symptoms at different blood levels of thyroid hormones. Anyway, how much do levels per se tell us, as their metabolism is obviously complex. People resistant to thyroid hormone (through thyroid hormone receptor beta) for instance have high EE, UCPs and hyperphagia. This actually sounds like, and is similar to, “standard hyperthyroidism,” but there is less receptor binding.

    Regarding athleticism, high carbohydrate is probably only necessary for those doing moderate to high intensity. Low and max intensity sports/events have little effect on glycogen, so it’s possible that an Olympic weightlifter for instance would have no problem shunning carbs. Self-selecting exercised rats eat more protein and fat than exercised chow rats and are leaner (I don’t know about their performance).

  22. Europe Life Expectancy Chart goes from east to west and reflects standard of living which includes among many other things better healthcare.

  23. Hi John,

    George is a smart guy. Is this his blog?: http://www.myspace.com/georgedhenderson/blog/540025897.

    I agree with your other two points. I am trying to acknowledge the experiences of several people who say that hypothyroid symptoms were alleviated when they ate higher carbs. I am not trying to make a general statement that hypothyroids should eat more carbs. Indeed, I rather like our standard diet unless personal experience shows that something else is better. I tried to make the point that sucrose consumption can make you feel better transiently, but is likely to be long-run negative.

    I generally agree that relatively few people would experience a significant change in athletic performance from eating more carbs; endurance athletes and those who train with great intensity in particular. But I think when you get to the Olympic level every little bit helps. Obviously it’s more complicated than just the amount, as the benefits from carb cycling show. The rat diets are interesting, I cited one in my book and Peter has blogged about this, but it varies significantly by strain, and with inbred strains it’s hard to draw strong conclusions. In any case it’s likely that rats need fewer carbs than humans, and that chow is too high in carbs.

    Hi Stan,

    Agreed, longevity correlates with many things besides carb consumption, and since carb consumption goes down as income goes up, that is a confounder. Still, longevity seems even better correalted to carb consumption than to income.

  24. Regarding carbs & athletes, Phil Maffetone has been coaching endurance athletes for a few decades. Some of them have been extremely successful (see Mark Allen). His dietary protocol is very similar to yours, relatively low-carb and high fat, interestingly.

  25. Hi Paul.

    I am new in Paleo diet (6weeks only) and I am still trying to find proper ratio of carb fat and protein. First I went very low carb may be 15-17%of calories only from veggies, but I have felt tired and not recover properly after my workout. I do not want to loose any weight just stay healthy and keep my (4-5days a week workout.) I do have problem with my period. When I have started to workout last february my period has stopped and I have had only once in september. I have done all test include hormonal profile, my doctor told me that it is not primary causes so I am trying to find out what I did wrong. I did not loose my weight from workout I keep my calories up to prevent it. Should I eat more to gain weight? Should I stopped to workout? I eat lots of fat like avocados coconut oil nuts daily and also from salmon and grassfed meat and butter. Many thanks for any advice

  26. Hi Misa,

    We recommend not counting carb calories from vegetables, as it costs nearly as many to digest them as you get, so they make very little net contribution to glucose balance.

    If you were eating only veggies, then, I would say you were too low carb by about 20% of calories. I would add some safe starches and fruits.

    Often that’s all that’s needed to restore periods, but micronutrient supplements are also beneficial, and if your workouts are intense then you may need more carbs. I wouldn’t stop working out unless you feel that workouts are making you ill.

    Best, Paul

  27. Thanks a lot for advice can I ask you how many fruit I can eat? I have started to be a bit afraid to eat it as much as I want.( I used to eat like 3 bananas, aplles, berries persimmon before I went paleo every day)So I just want to make sure it is ok to eat banana before my workout and some (1cup) of berries after it? Can I eat fruit also in any time not only with workout windows? Sorry for my english I am living in europe so I hope you understand

  28. Hi Misa,

    I think a pound (1/2 kg) per day would be reasonable, but there’s no hard number. If you don’t eat starches at all then you need more fruit, maybe 1 kg; if you like and eat starches then you need less fruit. I personally eat mostly starches with 2 pieces of fruit a day.

    You can eat fruit anytime, but it’s best to keep it away from polyunsaturated fat. So it’s a better breakfast / snack / dessert than meal food.

  29. Paul,

    Hmm, I actually haven’t seen that site of George’s. I was actually referring to this one: http://hopefulgeranium.blogspot.com/2011/12/hep-c-treatments-in-5-words.html

    I think they are the same going backward from your link, but the above blogspot one has more recent entries.

  30. carb intake and longevity–http://www.mattmetzgar.com/matt_metzgar/2012/01/carb-intake-in-healthy-centenarians.html

    seems you can live long and indulge in those badboys =)

  31. Hi Lenny,

    Most studies show centenarian diets to be pretty similar to those of the society as a whole, while supercentenarian diets are generally low-carb high-fat.

    Which suggests that the loss of longevity from eating a normal amount of carbs is less than 10 years.

  32. Hi Paul:
    My T3 is lower part of normal range and no issues with TPO antibodies or Hashi so i assume my thyroid is good.Perhaps the low end of normal range of Free T3 is due to being low carb. You said the following :

    “I personally eat mostly starches with 2 pieces of fruit a day”.

    How does this translate to calories that you consume between starch and fruit? 1 cup of rice, and then fruit for ex? 1 cup of cooked rice is about 200 calories or 50G. How much protein are you then consuming? Thanks much.

  33. Hi Paul — I just saw my doctor today about my Hashi’s, and he related this to gut dysbiosis (from symptoms only, as I have had no lab tests to evaluate this). He recommended supplemental L-glutamine. Is this something you would recommend, or advise against?

  34. Hi Steve,

    I eat typically 400 calories a day from starches, maybe 100-200 calories from fruit and sugary vegetables.

    I tend to be low in protein, 200-300 calories per day.

    Hi Kathy,

    No, I usually don’t recommend glutamine. I know the majority opinion favors it. But some pathogens can metabolize it, as well as gut cells. I tend to favor complete protein sources and easily digestible carbohydrates.

    If you want to try it, I would suggest trying an extra high dose at first, to see if it makes you feel better or worse, before deciding whether to continue at a lower dose.

    Best, Paul

  35. Paul, “fructose has been known for many years to accelerate the oxidation of ethanol(by about 80%).Oxygen consumption in the presence of ethanol is increased by fructose more than glucose( Thieden and Lundquist,1967). Besides removing the alcohol from the body more quickly, it prevents the oxidative damage, by maintaining or restoring the cell’s redox balance, the relitively oxidized state of the NADH/NAD+,lactate/pyruvate, and GSH/GSSG systems.” Dr. Ray Peat. I have done a little test on myself, before drinking any alcohol, I’ll eat a TBS of coconut oil and 2 TBS raw honey, then drink away. At the end of the night,I’ll eat the coconut oil/honey again and go to bed.I have done this three different times, and have yet to have a “hangover”. In fact, I actually have woke up at my usual time with no ill effects at all. Just my two cents.

  36. i’m guessing that video of the kid was done tongue-in-cheek. intended to show the myth (?) that sugar makes kids hyperactive.
    But your “adrenaline-promoting effects” interpretation may make more sense.

    “Where there’s sugar, there must be hyperactive kids – or so says conventional wisdom.
    Science says otherwise. An abundance of published randomised controlled studies have been unable to find any difference in behaviour between children who ate sugar (from lollies, chocolate or natural sources) and those who did not.
    Even studies that included children with attention-deficit/hyperactivity disorder (ADHD) could not detect any meaningful difference between the behaviour of children who ate sugar compared with those who did not” http://theconversation.edu.au/mondays-medical-myth-sugar-makes-kids-hyperactive-1009

    “studies done over the last 40 years suggest it’s not the sugar per se that can aggravate hyperactivity. It may be the colourings and preservatives and maybe caffeine that’s included with the sugar that can affect a small proportion of kids” http://www.abc.net.au/dimensions/dimensions_health/Transcripts/s776185.htm

  37. Can you just make me sure that when you counting carb you do not include veggies? I mean when I eat spinach lettuse, cabbage, celery,carrots all have some carbs and when I eat large amount of them it can be 75grams a day so you do not consider these carb in your calculating of carbs? When you write that 600 cal from carb it means that 600cal come only from safe starch( potato rice, fruit) ? Thanks a lot Sorry I am just confused.

  38. Sam,

    ”We recommend not counting carb calories from vegetables, as it costs nearly as many to digest them as you get, so they make very little net contribution to glucose balance.” Paul Jaminet

  39. Why do you take one study and focus on the adrenalin response and not highlight any of the benefits or provide other studies that show the same effect?

    Just for everyone who didn’t read the study, every group except for sucrose PO/C lost fat at the expense of lean mass. Sucrose C gained lean mass while losing fat mass and sucrose PO slightly gained fat mass(which is due to there higher fat intake compared to the other groups) but gained the most lean mass. The sucrose groups also had the highest metabolism and were able to eat the most amount of calories without gaining fat.

    Now on to the adrenaline issue, its pretty obvious paul doesn’t understand the issue 100%(honestly I don’t either).

    “Food deprivation and dietary sucrose supplementation have been shown to alter norepinephrine (NE) turnover in specific sympathetic target tissues. Our data indicate that these changes in turnover are not reflected by changes in plasma NE. Therefore, NE turnover rates and plasma NE concentration may not be equivalent indices of sympathetic activity.

    “In contrast to the effects on thermogenesis, protein and fat intake did not alter sympathetic nervous system (SNS) activity, as estimated by plasma norepinephrine (NE) levels, whereas glucose intake significantly increased NE levels. ”

    In this study glucose raises NE significantly compared to pro/fat.

    “Adrenalectomy (ADX) changes CRF and NE activity in brain, increases ACTH secretion and sympathetic outflow and reduces food intake and weight gain; all of these effects are corrected by administration of adrenal steroids. Unexpectedly, we recently found that ADX rats drinking sucrose, but not saccharin, also have normal caloric intake, metabolism, and ACTH. Here, we show that ADX (but not sham-ADX) rats prefer to consume significantly more sucrose than saccharin.”

    Sucrose normalizes ADX rats i.e. they normalize NE

    sympathoadrenal activity is linked to smaller waist, lower BMI and lower BP – http://www.ajcn.org/content/87/6/1596.full).

  40. If NE was being released to make room for fructose why do protein and fat not elicit the same response? Shouldn’t the insulin spike of protein raise adrenalin to free up glycogen from the liver?

  41. Hi Kevin,

    Interesting, thanks. Perhaps a worthwhile addition to Stabby’s alcohol protocol.

    Hi Darrin,

    I recognize that sugar doesn’t have such an effect in most people, but I believe it does in some. It may take an excess combined with some pathology to make the effect visible, but I’m doubtful it’s solely due to food colorings and preservatives.

    Hi cliff,

    It’s not possible in one post to address every issue completely. In any case I don’t normally discuss hormonal biology because it is too complicated and doesn’t normally provide much insight into what we should do.

    But since some Peat-atarians are claiming adrenalin reduction as a benefit of sugar consumption, it seemed worth noting that in the right circumstances sugar will raise adrenalin.

  42. It raises NE turnover but according to the first study “NE turnover rates and plasma NE concentration may not be equivalent indices of sympathetic activity.”

    If you look at the studies I posted you will see sucrose seems to normalize NE response.

  43. Salt+sucrose is supposedly the biggest stimulator of NE according to one study, yet salt+sugar is the number one recommendation to help sleep on rays diet. How is that something that puts in flight or fight also enables you to sleep soundly?

  44. They were only on the diet for 7-14 days.

    There are lots of variables that you don’t seem to account for. Low-Carb people know about how adaptation is needed on their diet and 7-14 days is not enough to adapt.

    How do we know sugar isn’t raising metabolism but these people in the study aren’t getting enough other nutrients(because of their deficient diet) to handle the increased metabolism so their adrenals need to come in and regulate blood sugar.

    The Peat diet eats nutrient dense foods like OJ(go look up the nutrients if you think its just fructose and water), eggs, milk, whole animal meat, other truly ripe tropical type fruits like sapodilla, coffee, cocoa, very well cooked greens/starches, salt/baking-soda and a little bit of sucrose to round out the diet so we get enough sugar.

    But if your Peat diet is low in nutrients and you add too much sugar you will start to become nutrient deficient starting in stuff like biotin,B6,copper that’s why we aren’t just pounding Mexican Cokes all day. My diet(which contains pure sucrose) is more nutrient dense than most in the world and I would wager it’s more nutrient dense than every Perfect Health dieters’ food intake.

    You act like this study(http://www.nature.com/ijo/journal/v21/n10/abs/0800494a.html) is the smoking gun on fructose’s toxicity and that “a high-carb sucrose-based diet [is] rather stressful for the body”.

    Well based on experience why does everyone seem to crave sugar when they are stressed?

    I tried starch diets vs sucrose vs fat diets and sucrose is the only thing that satisfies me and the only diet that truly healed me.

    You can feel the anti-stress effects. I can get my adrenaline high and go into flight or fight response and it feels nothing like when I just ate a big meal of nutrient dense foods that included lots of sucrose.

    Please try for yourself and tell me that sucrose raises adrenaline and makes you feel like flight or fight.

    • I see this thread is about a year old, so not sure you’ll see this Keenan, but I’m intrigued by the benefits you’ve found (I also have a major foot pain issue) yet at the same time I’ve found Peat’s recommendations so strange that I thought hopefully you could answer a couple of questions.

      Do you take a thyroid supplement like Ray Peat, and also aspirin as he recommends? I would think that the aspirin alone would thin the blood enough to improve circulation, thus decreasing foot pain.

      As for OJ — I don’t see how it’s nutrient dense at all. High in water and sugars, also potassium, but that’s about it. ???

      Thanks in advance,


  45. Hi Keenan,

    It’s just a single blog post, it’s not intended to be a comprehensive analysis of Peat’s ideas, just throwing out food for thought.

    The main takeaway is that it’s not as simple as saying that “filling liver glycogen is good” or “sucrose fills liver glycogen and that reduces adrenaline levels.” In fact sucrose can and usually does have harmful effects.

    That is not to say that PUFA avoidance and a micronutrient-rich diet may not go a long way toward making sucrose benign. I’ve always said in our book and on this blog that fructose is dangerous in combination with PUFA, and that micronutrient-rich diets help people cope with dietary toxins.

    The “Peat diet” that you describe is very similar to mine save for the “little bit of sucrose to round out the diet”. I’m glad you acknowledge that that little bit of sucrose can have negative effects in some people.

    I think positive experiences with sucrose like yours are interesting. When you say “you can feel the anti-stress effects,” I am sure you are feeling better. But what does “better” mean for long-term health? People often feel good after ingesting candy. It doesn’t mean it’s a proven health food. It takes more than your feelings to establish the long-term health effects of sucrose, or even its effect on adrenaline.

  46. Sucrose in the context of OJ takes away all of the harmful effects.

    I meant if you add too much pure sucrose you can get nutrient deficiencies because of increased metabolism without sufficient nutrients.

    Before I gave in to my sugar cravings my foot had a muscle pain that wouldn’t go away for close to a year on a diet just like Perfect Health Diet.

    Animals have been eating sucrose for millions of years. The long term health benefits of fruit/honey/nectar have been proven and the burden of proof is on you to show fruit has long term disease effects.

  47. Thank You for the wonderful article.
    Personally, I’ve realized when I eat low carb, I feel “uncomfortable.” I think it’s hypoglycemia but I am no professional doctor or anything. I get brain fogs, lots of underarm sweat, and even difficulty in speaking. Moderate amounts of carbs definitely seem to work for me:)

  48. Great post!

    What concerns me is the fertility issue. Specifically, does a higher carb intake result in increased fertility because of increased sperm production and/or motility, or would a slightly higher carb ratio have an effect on sex drive? If low carb can result in a lower t3 to t4 ratio, I would assume that would have an effect on libido.

    Consuming strict no-starch Paleo sent my sex drive plunging. Strict PHD (about 20% safe starch calories) has partially restored my sex drive, but it’s still quite low compared with what I’m used to. Could a 40% carb ratio, closer to the 250g upper limit, result in increased libido? If forced to choose, I’ll take a shorter, hornier life, personally 😉

  49. Hi Ken,

    Re sex drive, everything is going to change together. If your evolutionarily-selected biology thinks it’s the right moment, health and food availability wise, for you to have children, it will promote libido, sperm production, and egg production all at the same time.

    I think you should try different carb ratios and find the ratio that best serves your life goals!

    Best, Paul

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