Category Archives: Low-Carb Diets - Page 3

Water Weight: Does It Change When Changing Diets? Does It Matter?

We’re now up to the final topic in the series reviewing experiences on the diet. Our final topic is the issue of weight gain and loss. This will take a few posts to explore. Next week will be “fat loss week.” This week, let’s look at the question of water weight.

Overweight people who come to the Perfect Health Diet from a high-carb diet seem to lose weight from the beginning. Here is a recent comment from Robert:

I started PHD a few weeks ago, after finding the blog, and then reading the book. I have only positive experiences to report…. I had been overweight in the past, and lost weight by low-calorie dieting on processed foods, along with strength training. After a while I would revert to some degree of overeating, and have to diet again. I’m mildly overweight now but I have been losing 2 lbs. per week on the PHD. Keep in mind this is before any calorie counting. I keep telling myself I will plug things in to Fitday, but so far my hunger is autoregulating itself and the weight is coming off.

However, some of our readers who came from very low-carb diets experienced immediate weight gains. One commenter on Amazon seemed to think this experience would be universal:

[I]f you are coming to the diet from a zero-carb or very-low-carb regimen, you can count on an immediate and substantial weight gain if you suddenly adopt the recommended intake of “400 carb calories [100 grams] per day of starchy tubers, rice, fruit, and berries.” (K. Hix)

Commenter Maggy reported a gain of 5 pounds in her first week:

Following your advice, I added back a bit of “safe starch” last week, and decreased protein intake, keeping sat fat and MCF pretty high. Well, I got on the scale today and have managed to put on 5 pounds! I’m trying to figure out what is going on and what I need to tweak. I do need to lose a good 20-30 lbs, and while I don’t want to compromise health, I also don’t want to put back on what I managed to lose doing a VLC diet.

Is this an adjustment period I need to get through? Maybe I’m one of those broken metabolism folks who has to stick with VLC?

Commenter Bill also experienced a quick gain of a few pounds, and wondered if it could be due to water weight:

After experimenting with adding modest amounts of “safe starches” to my much lower-carb routine, I have noticed a modest weight gain of 3-5 lbs. I wonder if it’s merely glycogen and water repletion.

Beth Mazur of agreed:

I also wouldn’t be surprised about weight gain. Presumably these folks are normally running on fairly low glycogen stores. Add some starchy carbs back, and the resulting water weight gain could be a handful of pounds presumably.

That’s an interesting question, so I thought I’d look into the matter.

Background: Glycogen, Glycoproteins, and Water Weight

Sugars are hydrophilic. If you put some water next to some sugar, the sugar will soak it up. As a result, a person’s water weight depends in part on the weight of sugars in the body. More sugars, more water, more weight.

It’s commonly stated that each gram of glycogen is associated with four grams of water; let’s take that as a general ratio for organic sugars.

A typical adult has around 500 grams of glycogen, roughly one-third in the liver and two-thirds in muscle. With associated water, this would add about 2.5 kg or 5 pounds to body weight.

But there are also several pounds of glucose in glycoproteins throughout the body:

  • Mucus in the digestive tract and airways may be as much as 80% sugar by dry weight.
  • The glycocalyx, a protective polysaccharide coat around cells, is primarily composed of sugars.
  • Hyaluronan, glucosamine, and other compounds that enable joints to move freely have much of their weight as sugar-water associations.

These sugar-containing molecules with their associated water add a lot of weight to the body. Glycogen we’ve said accounts for as much as 5 pounds; mucus probably accounts for several pounds at least; and other glycoproteins must add at least a few pounds more.

Are Glycogen and Glycoproteins Lost on a Low-Carb Diet?

It’s commonly asserted that much of these sugar-containing molecules, and their associated water, are lost on a low-carb diet. From a review of Gary Taubes’ Why We Get Fat, linked today by CarbSane:

[B]etween 5-10lbs of weight are lost on a low-carb diet due to the mobilization of the water stored with glycogen …

I argued in my “zero-carb dangers” series that a danger of zero-carb dieting was that the body would downregulate production of glycoproteins; and that reduced production of these might be quite dangerous.

For instance, reduced production of mucus in the digestive tract might increase the risk of gastrointestinal cancers, bowel diseases, and entry of infectious pathogens through the gut.

If it’s true that low-carb diets reduce water weight by 5 to 10 pounds, there must be a substantial loss of sugar-containing molecules. This is hardly likely to be healthy. Glycoproteins are essential for good health. Indeed, the evolution of glycoproteins was a prerequisite for the evolution of multicellular life!

So I would find this kind of water-weight loss quite alarming.

Let’s look for some data to see if it actually happens.

From High-Carb Diet to Fasting

In our earlier post on fasting for migraines, commenter js290 linked to a very nice post by Ned Kock, in which he talked about the components of weight loss during starvation. Ned posted this picture, taken from a textbook [1]:

Over 30 days of fasting, almost half the weight lost is from fat and almost half from water; small amounts of protein and sugar are lost.

In the first few days, water loss dominates. In the first 48 hours, 3.4 kg are lost, of which roughly 0.35 kg are glycogen, 0.1 kg protein, 0.3 kg fat, and 2.65 kg water.

So in the first two days of fasting, fully 5.8 pounds of water are lost. That’s remarkable.

Presumably, if this person had been returned to his normal diet, that weight would have been regained in a few days.

If the water loss was triggered by a loss of carbohydrate (in glycogen and glycoproteins), then a very low-carb diet might have had the same effect as the fast.

From High-Carb to Low-Carb Diets

There are some metabolic ward studies looking at what happens when people adopt low-carb diets. Here’s one that looked at an Atkins-style diet. [2]

The subjects entered the metabolic ward but continued to eat their normal diet on days 1 through 7, to provide a baseline. Then they adopted an Atkins-style diet for 2 weeks. Carbohydrate was reduced to 21 g (80 calories) per day, and they could eat as much fat and protein as they wished.

The results:

During the low-carbohydrate diet, mean body weight decreased by 2.02 kg from 114.43 kg (last day of the usual diet) to 112.41 kg (last day of the low-carbohydrate diet) …

During the low-carbohydrate diet, mean body water decreased from 46.30 kg to 45.94 kg. Body water decreased in 6 patients, increased in 3 patients, and did not change in 1 patient. After subtraction of body water, mean body weight decreased from 68.13 kg to 66.48 kg. [2]

In other words, water weight hardly changed. The weight loss was accounted for by fat loss, which was understandable because the subjects reduced their calorie intake by 946 calories per day. [2]

So in this study, water weight loss averaged only 360 g (0.8 lb), and some patients actually gained water weight on the low-carb diet!

So it looks like going from a high-carb diet to a low-carb diet needn’t lead to much loss of water weight.

From Low-Carb Diet to Fasting

I looked for some papers on what happens when a low-carb dieter starts a fast. I found this:

In her book ‘Living on Light’, Jasmuheen tries to animate people worldwide to follow her drastic nutrition rules in order to boost their quality of life. Several deaths have been reported as a fatal consequence. A doctor of chemistry who believably claimed to have been ‘living on light’ for 2 years, except for the daily intake of up to 1.5 l of fluid containing no or almost no calories was interested in a scientific study on this phenomenon.

The 54-year-old man was subjected to a rigorous 10-day isolation study with complete absence of nutrition. During the study he obtained an unlimited amount of tea and mineral water but had no caloric intake….

[The man experienced] a mean weight loss of 0.26 kg/d … [3]

If his weight loss of 260 g/day consisted of 130 g protein and 130 g fat – a plausible mix – then he was expending about 1700 calories per day. This is very plausible, and leaves little room for water weight loss.

So when a low-carb dieter starts a fast, he may lose hardly any water weight at all!

Summary and My Own Experience

These studies are inconsistent. If going from a high-carb diet to a low-carb diet doesn’t produce water weight loss, and going from a low-carb diet to fasting doesn’t, then why would going from a high-carb diet to fasting?

I confess I was surprised by the level of water loss reported by Ned’s source. I fast moderately often, and I lose typically around 1 pound during a 36 hour fast. Shou-Ching’s experience is similar. That doesn’t leave much room for water weight loss.

But clearly, some people do experience large losses of water weight when they adopt a low-carb diet or a fast, and then regain it upon carb re-feeding.

I think we have to conclude that the phenomenon of water weight loss on low-carb diets, and water weight gain on carb re-feeding, is variable across persons. In some persons it happens, and in others it doesn’t.


I think those sugars serve important functional purposes. Glycoproteins are essential for health. Glycogen is a desirable reserve that helps the liver manage blood glucose and muscles exert force.

Maggy asked if she was metabolically broken because she gained 5 pounds in a week by adding carbs back in. Now, a lot can happen in a week, including significant changes in fat and protein mass, and water weight changes due to changes in sodium levels. Low-carb diets tend to lead to salt loss, so that may have been a factor.

But if the weight gain was entirely due to restoration of sugar and water levels, then I’m reluctantly led to the conclusion that Maggy may indeed be “metabolically broken.” The brokenness is not in the gain of bodily sugars when she eats the carbs; it’s in the loss of these important sugars on her very low-carb diet!

If it’s unhealthy to lose those sugars, and if a metabolically healthy person can sustain the body’s sugar and water levels through a fast, then the loss of sugars on either a low-carb diet or fast suggests a damaged metabolism.

As much as Maggy wishes to lose weight, it is important to lose weight from adipose cells, not from water and glycoproteins. Her rapid ~5 lb weight gain upon shifting from a very low-carb diet to the Perfect Health Diet might have been a very good thing.


CarbSane has begun a series on water weight, and has interesting numbers on water weight in adipose tissue and lean tissue, and how water weight varies between obese and lean persons. This post introduced several papers, and a follow-up contributes an interesting analysis and suggests that movement of fatty acids between adipose and lean tissue may be involved in water weight changes.

I didn’t know that extracellular water weight in tissues was so variable. Thank you CarbSane! 


[1] Wilmore, J.H., Costill, D.L., & Kenney, W.L. (2007). Physiology of sport and exercise. Champaign, IL: Human Kinetics. Cited by Ned Kock, “The amounts of water, carbohydrates, fat, and protein lost during a 30-day fast,”

[2] Boden G et al. Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. Ann Intern Med. 2005 Mar 15;142(6):403-11. Full text:

[3] Heusser P et al. Nutrition with ‘light and water’? In strict isolation for 10 days without food – a critical case study. Forsch Komplementmed. 2008 Aug;15(4):203-9.

Short-Term Effects of Adding Carbs to Very Low-Carb Diets

In my last post, I noted that

So far, all the negative experiences [from adoption of our diet] I am aware of have come from low-carb dieters who had difficulty after adding carbs and/or cutting protein….

It’s interesting that the same dietary change – adding “safe starches” to a low-carb Paleo diet – made some people feel better and others worse.

In thinking about why adding starches can cause short-term trouble for some people, my first thought was a fascinating post from two years ago by Peter Dobromylskyj of Hyperlipid. Peter noted:

Bacterial endotoxin is a breakdown product of the cell wall of gram negative bacteria. It’s a lipopolysaccharide and even quite small amounts of it are extremely unpleasant….

Now the scary thing is that eating a high fat meal, probably based on any fat which generates chylomicrons, markedly increases your uptake of endotoxin from your gut, which is obviously full of gram negative bacteria. Eating short chain fatty acids or carbohydrate [1] does not have this effect.

Endotoxins are fat-soluble, and so fat carries them into the body. The paper Peter cited actually found an increase in blood endotoxin levels after people were fed a high-fat meal:

In humans, no significant relation was observed between cardiovascular disease risk factors, carbohydrate and protein intakes, and plasma LPS concentration. Conversely, positive correlations were observed with fat and energy intakes. [1]

The same effect was found in mice:

Compared with the control mice, mice fed a high-energy diet showed an increase in plasma LPS. However, in mice fed a high-carbohydrate diet, the increase in plasma LPS was blunted compared with mice fed a high-fat diet.

The conclusion:

Experimental data suggest that fat was more efficient in transporting bacterial LPS from the gut lumen into the bloodstream. [1]

Does this mean that one should avoid dietary fat?  No, because it turns out the body regulates the amount of endotoxin entering the body. So a high-fat diet causes the immune system to exert greater control over gut bacteria. Peter writes:

Then came a fascinating random paper [2] through my wife’s journal club meetings … It’s about superinfection with resistant bacteria when broad spectrum antibiotics are used. This is a routine problem for anyone in medicine, especially patients. The concept is very simple, you kill off the susceptible commensal bacteria in the gut and resistant pathogens have no competition, so they have a field day and superinfection causes severe problems for the unlucky patient.

Simple, straightforward and wrong.

It turns out that the immune system, that is the innate immune system (of course), continuously monitors the contents of the gut by looking at endotoxin production. Lots of bacteria mean lots of endotoxin and an active, on-guard innate immune system. Kill off 99% of your gut bacteria and exdotoxin production drops. The innate immune system goes on vacation and clostridium difficile gets in and wipes out your granny.

Simple administration of oral endotoxin to the experimental mice stopped this effect completely.

Apparently, the human body evolved to favor having a certain population of commensal gut flora. When the population is too low, immune defenses are lowered to allow gut bacteria to multiply. When the population is too high, antimicrobial peptides are released into the gut to control pathogen numbers.

Thus, during gut infections adding probiotic bacteria may help defeat pathogenic infections by causing the body to increase its immune defenses. The body is actually trying to control the numbers of probiotic bacteria, but in doing so it makes compounds that kill pathogens.

Removal of tiny numbers of probiotic bacteria can lead to a huge multiplication of pathogens:

Administration of the broad-spectrum antibiotic combination metronidazole, neomycin and vancomycin (MNV), to which vancomycin-resistant Enterococcus (VRE) is resistant, markedly increases colonization of the small intestine, caecum and colon with VRE…. It remains unclear, however, why elimination of the relatively sparse microbial flora of the small intestine increases the number of VRE by over 100–1,000-fold. [2]

It’s possible that this effect may be able to work in reverse – that addition of the small number of bacteria in a probiotic capsule can diminish the much larger population of an acute infection by 100-fold. I’ve noticed that swallowing probiotic capsules can be extremely effective against food poisoning. If you ever get diarrhea from a bad meal, take handfuls of probiotics every few minutes. You’ll be cured remarkably quickly.

The Gut of a Zero-Carb Dieter

On a zero-carb diet – especially an entirely plant-free diet like the one Charles Washington eats – lack of food will cause the population of gut bacteria to dwindle.

As in a gut depopulated of bacteria by antibiotics, this diet will cause the gut to let down its immune defenses. The body will reduce its production of antimicrobial peptides in order to help gut bacteria survive.

Perversely, this may make any pathogens that enter the body with food more likely to enter the body. It also may allow pathogens to gain a foothold in the gut. Thus, heightened infectious disease risk could be another long-term danger of zero-carb diets.

What Happens When A Zero-Carb Dieter Reintroduces Starches?

When a zero-carb dieter starts eating plant foods, suddenly gut bacteria have a lot of food, and can multiply many-fold. Bacteria can double their numbers in 20 minutes, and yeast in a few hours. That means that bacterial populations can increase 8-fold in an hour, 4000-fold in 4 hours, and ten million fold in 8 hours. Yeast can increase 4000-fold in 24 hours.

So it doesn’t take long – the very first day – before gut bacteria have multiplied by huge proportions. In the course of their fermentation, they’ll release a lot of gas, causing some bowel distress.

And along with greater numbers comes greater endotoxin release. Any dietary fats carry these endotoxins into the body. This rise in endotoxin load triggers an immune response that includes release of antimicrobial peptides, killing gut bacteria and releasing more endotoxins.

This rise in endotoxin levels and the resulting immune response may resemble a brief illness. Some known effects of a sudden rise in systemic lipopolysaccharide levels:

  • Depression [3] and depressive-like behavior [4].
  • Impaired athleticism [5]. 
  • Reduced appetite [6, 7].
  • Fever, vasoconstriction and endothelial dysfunction. [8]

Of course these effects would be only temporary. In a matter of days to a week, the immune system should re-establish an equilibrium with the gut flora and the new diet. Gas and bloating in the gut should be reduced (unless pathogens have been able to establish an enduring infection first). Endotoxin levels in the body should return to the evolutionary optimum. Higher production of antimicrobial peptides will maintain a limited gut bacterial population, even though carb intake has increased.

My Experience

My own experience is consistent with some of these expectations. When I went from zero-carb to including carbs – in my case, the change was adding fruit only, starches didn’t start for another year – my abdomen became bloated and I had gas. It was remarkable:  the very first day I ate fruit, my belly bloated up. It seemed to leave me with a lasting infection, because both the bloating and various digestive problems lasted several years. Probably the scurvy that I also had at that time was a big contributor; until I fixed the scurvy I also had gallbladder problems, and developed diverticulitis during this period, diagnosed by a barium enema.

I believe the main factor in the bloating was a colonic yeast/fungal infection that may or may not be completely gone today (it is certainly much diminished). The bloating was increased whenever I developed fungal skin infections. I suspect the yeast took over my colon while my immune defenses were depressed on the zero-carb diet and vitamin C deficiency, and multiplied immensely as soon as they had access to plant foods.


This hypothesis matches some but not all of the first-couple-of-days symptoms experienced by Don Matesz and his commenter SamAbroad when they cut protein and increased starches. SamAbroad became “hungry and cranky”; Don noted “decline in mood and … increase in hunger and intestinal gas and a disruption of bowel function.” In short:

  • Gas, bloating, intestinal distress.
  • Cranky mood.
  • Hunger.

The first two are consistent with a rise in endotoxin levels. The last isn’t.

However, I can imagine a few reasons why a shift from meat to starches may have made them hungry:

  • Protein is notably satiating, one reason why high-protein diets are often effective for weight loss. Mixed carb and fat, on the other hand, makes a good dessert. As we have all witnessed, many people say they are stuffed after dinner but get hungry again when they see desserts.
  • Or maybe the calories lost from the reduction in meat were not fully replaced. Plant foods have far fewer calories per pound than meat, and many people overestimate how many calories are found in plant foods. In cutting meat from

The body should adjust appetite to the diet, but this may not happen in the first few days. In short-term (3-day) trials of food mix alteration, people who increased carbs ate more food than people who increased protein. [9]

I don’t know if these explanations are correct in the specific cases of Don and SamAbroad. (Indeed, I was very surprised Don had any trouble at all, since he already eats our safe starches and I am pretty sure he also eats within our recommended optimal range of macronutrients — hat tip to commenter Beth Mazur of for a link to one of Don’s meal analyses in which he ate our recommended calorie ratio.) However, I think many people who have been on zero-carb diets can expect short-term gut distress when they first restore carbs to the diet.

In people with healthy gut flora, this should disappear in a few days. In others, like me, who have pathogenic gut populations, a gut infection may become entrenched and take longer to get rid of. Still, overall I think the inclusion of dietary carbs, and the resulting enhancement of intestinal barrier immunity, is likely to lead to long-term improvement in the body’s protection against infectious diseases that enter through the gut.


[1] Amar J et al. Energy intake is associated with endotoxemia in apparently healthy men. Am J Clin Nutr. 2008 May;87(5):1219-23.

[2] Brandl K et al. Vancomycin-resistant enterococci exploit antibiotic-induced innate immune deficits. Nature. 2008 Oct 9;455(7214):804-7.

[3] Weidenfeld J, Yirmiya R. Effects of bacterial endotoxin on the glucocorticoid feedback regulation of adrenocortical response to stress. Neuroimmunomodulation. 1996 Nov-Dec;3(6):352-7.

[4] Fu X et al. Central administration of lipopolysaccharide induces depressive-like behavior in vivo and activates brain indoleamine 2,3 dioxygenase in murine organotypic hippocampal slice cultures. J Neuroinflammation. 2010 Aug 2;7:43.

[5] Sparkman NL et al. Effects of intraperitoneal lipopolysaccharide on Morris maze performance in year-old and 2-month-old female C57BL/6J mice. Behav Brain Res. 2005 Apr 15;159(1):145-51.

[6] Stengel A et al. Lipopolysaccharide differentially decreases plasma acyl and desacyl ghrelin levels in rats: potential role of the circulating ghrelin-acylating enzyme GOAT. Peptides. 2010 Sep;31(9):1689-96.

[7] Rorato R et al. Prostaglandin mediates endotoxaemia-induced hypophagia by activation of pro-opiomelanocortin and corticotrophin-releasing factor neurons in rats. Exp Physiol. 2009 Mar;94(3):371-9.

[8] Feng SY et al. Acute and chronic effects of endotoxin on cerebral circulation in lambs. Am J Physiol Regul Integr Comp Physiol. 2010 Mar;298(3):R760-6.

[9] Coelho JS et al. Selective carbohydrate or protein restriction: effects on subsequent food intake and cravings. Appetite. 2006 Nov;47(3):352-60.

Experiences, Good and Bad, On the Diet

A number of people have now given us feedback after starting the diet, and I think this is a good time to review the effects, good and bad, that people have experienced.

In upcoming posts, I’ll discuss the negative experiences further and explore possible causes.

Positive Experiences

It’s gratifying that most people who have tried our diet have reported very positive experiences. Those who read the comment threads or Amazon reviews will have seen some of them; I get others via email.

Here are two from Amazon reviews:

I have battled Celiac disease for some time and got about 80% better with a Paleo diet… but the Perfect Health Diet was the first book that could finally answer that last 20% with science based logic. (Jordan Reasoner)

UPDATE: Jordan has an e-book, SCD Lifestyle: Surviving to Thriving, which looks great for bowel disease sufferers. He gives us an update on his personal progress in the comments.

I can’t believe how much better I feel!…

I had been eating (very) low-carb and high-protein for the better part of a decade – and I had gotten a lot of practice arrogantly dismissing suggestions (from any source) that I should change anything about my diet….

Results: (after 1.5 months or so.)

  1. I’m no longer “brain-dead” and unable to think in the evenings after work.
  2. I no longer have fruit or chocolate cravings.
  3. I’m much happier, and wake up looking forward to the day.
  4. I’ve been much more social.
  5. The extra starch has not resulted in weight gain. (I always gained weight when eating carbs before.)
  6. It looks like the fasting (which I’ve never tried before) is helping my alertness and also contributing to healthy weight loss.

It took less than a week for me to notice dramatic changes….

I can’t recommend this book highly enough. (gp2x)

Here are two from the last few days’ comments.

Yours is by far, the best Paleo / Ancestral diet that makes sense….  I was very strict Paleo for a good 8 months, and yes felt fantastic and lost 10ks etc.  But then started feeling tired, moody.  Enter some carbs (from the suggestion of your book) in the source of potato and rice and taro – and now I’m feeling a whole lot better.  Did I put on weight.  Of course not!  Essentially now I eat what my body craves.  I can listen to it now and it responds accordingly.  It knows when it needs more carbs (eg., after exercise).  And it knows how much as well. (Lisa Weis)

Since reading Gary Taubes’ Good Calories, Bad Calories my life has been transformed. Who knew that butter was a healthy food.  Previous to reading GCBC I was a fruit fiend.  I ate bowls and bowls of cherries this past summer and wondered by I could not lose weight.  I reached my weight loss goals by eliminating grains and limiting dairy to butter and cream and reducing fruit intake.  That said, over the last month or so, I was wondering why my body seemed to be drying out from the inside out.  I want to tweak my diet to optimum health and found your book. The information about the importance of mucin was helpful.  What was missing in my diet was the carbs that you and the missus recommend.  Sweet potatos, white rice etc.  Maybe less protein than I’ve been eating and more saturated fat.  (I’m alarmed by the stomach and other cancers suffered by long term adherence to the Optimal diet …)  I’m having better results every day.  I am fascinated that I have a laboratory of my own body to put your ideas to a test and have them show positive results.  Thank you both so much for your work and above responses to questions and comments. (Doris)

I think these positive experiences are impressive considering that most of our readers have come from the low-carb Paleo community. Low-carb Paleo diets are far healthier than the Standard American Diet, and so improving health further is quite an accomplishment.

Another group that we are trying to help are people with chronic diseases. Probably most readers who did not arrive from the low-carb Paleo community have come from the chronic disease community. It’s a little early to report results, but at least some people are finding promise in our diet. Natalie wrote:

As someone dealing with chronic disease (a very unfun combination of Lyme, Babesia, and Bartonella), I know I’m always looking to find out more of what has worked and what did not work for others.

This blog along with many of the readers of this blog have been a tremendous help to me personally.  For example, I now know I can avoid the daily “coma naps” if I don’t go crazy on the carbohydrates.  I’ve actually received some excellent diet advice from my doctor, but he never told me to chill on the carbs!  (Natalie)

Ketogenic diets are frequently mentioned by us as potentially therapeutic for many diseases. I’ve blogged previously about Claire’s discovery that ketogenic diets help her gastroparesis and Rob’s suppression of his lifelong migraines through fasting and ketogenic dieting.  

As more chronic disease sufferers try the diet – for instance, Darren who has Lyme disease – we hope to prove that the Perfect Health Diet in conjunction with antibiotic therapies can lead to cures for these difficult-to-treat conditions.

Negative Experiences

So far, all the negative experiences I am aware of have come from low-carb dieters who had difficulty after adding carbs and/or cutting protein.

Don Matesz is an interesting case, because his own diet was already a “Perfect Health Diet.” His diet, if I’m not mistaken, was in the low end of our carb range and high end of our protein range. As a test he reduced protein and added carbs, heading toward the high end of our carb range and low end of our protein range. He didn’t like the results:

Just to experiment, for a couple of days Tracy and I reduced our meat intake by half.  I reduced my meat intake from more than a pound daily to just about one-half pound, and, as the Jaminets suggest, replaced the protein with starchy carbohydrates (potatoes and sweet potatoes).  For both Tracy and I, this resulted in a noticeable decline in mood and a dramatic increase in hunger and intestinal gas, along with a disruption of bowel function….

UPDATE: Don says that he does best eating above the bottom end of our optimal carb range, but that for years he has gotten into trouble whenever carbs reach 100g/day (the middle of our optimal range). It sounds to me like an unresolved gut dysbiosis.

Don’s commenter SamAbroad had a similar experience with reducing protein intake:

But I’ve also been following the PHD, and to be honest, I am so hungry and cranky when I restrict protein.

UPDATE: SamAbroad turns out to be our Sarah, and she says that the Perfect Health Diet “has been one of the best things I’ve ever done for my health.” Maybe we should move her to the Positive Experiences group!

I’m still following the diet, I eat circa 100g carbs from starch a day not including veg and this has been one of the best things I’ve ever done for my health along with including a vitamin C supplement. My low-level depression and anxiety have completely disappeared and the diet is considerably more varied and easier to stick to than VLC.

Sarah’s issue is that she needs to eat at least the midrange of our carb+protein “plateau range,” for reasons as yet unknown.

Chris Masterjohn had trouble with sweet potatoes:

Although sweet potatoes are considered a safe starch on the Perfect Health Diet, they are not very safe for me. When I discovered how yummy sweet potato fries are, I started eating several sweet potatoes per day. Within a few days, I was limping and my neck was stiff. By the end of the week, my limp was extreme. I looked online to see if I was eating anything high in oxalates, and sure enough, sweet potatoes are loaded with them. My symptoms dramatically improved after one day off sweet potatoes and were gone the second day.

Chris’s commenter Lisa also had trouble with sweet potatoes:

I’ve been very achy since I started eating sweet potatoes daily. Why would some of us be maladapted to oxalates?… I’m wondering if after a long stint of LC/paleo eating I’ve become intolerant to oxalates or to starch in general.

UPDATE: We discuss possible reasons for problems with sweet potatoes here.

Several people have gained weight after starting the diet. This Amazon review doesn’t come right and say that the reviewer experienced weight gain, but I’m guessing that was the case:

It is worth emphasizing what another reviewer noted: The Perfect Health Diet is not focused on weight loss. In fact, if you are coming to the diet from a zero-carb or very-low-carb regimen, you can count on an immediate and substantial weight gain if you suddenly adopt the recommended intake of “400 carb calories [100 grams] per day of starchy tubers, rice, fruit, and berries.” (K. Hix)

From the comments, Maggy reported weight gain:

Following your advice, I added back a bit of “safe starch” last week, and decreased protein intake, keeping sat fat and MCF pretty high. Well, I got on the scale today and have managed to put on 5 pounds! I’m trying to figure out what is going on and what I need to tweak. I do need to lose a good 20-30 lbs, and while I don’t want to compromise health, I also don’t want to put back on what I managed to lose doing a VLC diet.

Is this an adjustment period I need to get through? Maybe I’m one of those broken metabolism folks who has to stick with VLC? (Maggy)

These negative experiences will be the subject of my next few posts.

Because individuals are so variable, it is often not possible to figure out what is going on without experimentation with different dietary variations and considerable communication. Therefore, I’m most grateful to people like Maggy who are willing to experiment and share their experiences with us.


It’s interesting that the same dietary change – adding “safe starches” to a low-carb Paleo diet – made some people feel better and others worse.

This series may also lead us into the question of trade-offs in diet. These trade-offs may cause different people to prefer different diets. For instance:

  • Shifting from lean-meat-and-vegetables to starches and fats may increase the pleasure of eating and improve health in some, but promote weight gain in others.
  • Higher protein may promote athleticism and fertility, but shorten lifespan (as it does in some animals).

In writing our book, we tried to present the evidence underlying all of our recommendations, and provide healthy ranges for the various nutrients with explanation why the reader might prefer to be at the high or low ends of the range. Our goal was to empower each reader to find his or her own “perfect health diet,” not to rigidly prescribe a specific way of eating.

But negative experiences on a diet can also have diagnostic value. For instance, when I first adopted a low-carb Paleo diet I developed severe fungal skin infections. The new diet revealed an infection I hadn’t known I had. For this reason, even negative experiences can be beneficial, as they may open a path to curing an underlying but hitherto concealed health problem.

We see this blog as a communal enterprise, in which we and our readers together try to discover the truth about diet and health. Therefore, we hope that anyone who does have negative experiences on the diet will not hesitate to report them in the comment threads and work with us to discover the cause.

Reflections on Our Book Inspired by Chris Masterjohn, I

Chris Masterjohn has put up a detailed review of our book. He calls my wife and I “awesome,” the book “excellent,” and awards “two thumbs up.” Thanks Chris!

Chris’s review led me to reflect a bit on our book, and I thought it might be appropriate to close the blogging year with a couple of posts about it. Specifically, I will:

  1. Clarify our argument for optimal macronutrient ratios. Chris spends a substantial part of his review discussing the issue of carbs, and I think readers may be interested in my perspective on the issues he raises.
  2. Look at the “big picture”. What is the state of dietary science, and where does it need to go? How close are bloggers and scientists to integrating the various perspectives and reaching the truth? What does our book in particular contribute to both popular and scientific debates?

Today I’ll discuss the carb issue.

Macronutrient Ratios and Carbohydrate Intake

Step One of our book is about macronutrient ratios. The key goal of Step One is to help readers understand how much of each macronutrient they need to avoid deficiencies and what levels will produce toxicity conditions.

For some macronutrients this is easy, because the evidence is fairly clear:

  • Protein. Roughly 5% of energy as protein is sufficient to avert a deficiency, and the evidence of toxicity is also fairly clear: protein over 40% of energy can be fatal, and there are less severe indications of toxicity at about 30% for adults, 20% for pregnant women, and 9% for infants.
  • Polyunsaturated fats. About 0.5% of energy will avert deficiencies of both omega-6 and omega-3 fats, and there are subtle indications of toxicity above about 4% of energy, with the indications becoming obvious above 10%-15% of energy.
  • Saturated and monounsaturated fats. These are benign at all intake levels: non-toxic in high doses, and impossible to become deficient in (except during starvation) because the body will manufacture them from carbohydrate or protein.

But determining the optimal intake range of carbohydrates is difficult, because unlike the other macronutrients there is no data that lacks confounding factors.

The main problem is that the main sources of carbohydrates in western diets – grains and sugar – contain food toxins such as gluten and fructose. So any benefits from reducing carbs could be the result of reduced toxin intake, not reduced carbohydrate calories.

We know these plant toxins are important, because populations that obtain carbs from “safe starches,” such as yam-eating Kitavans, rice-eating Chinese and Japanese, and potato-eating Irish have been notably healthy. (See, for instance, our China Study posts, our wheat series, and Stephan’s Kitava and potato posts.)

However, in none of those “safe starch” eating populations do we have good data on how health outcomes vary with a differing mix of carbohydrates vs. saturated and monounsaturated fat.

With data lacking, our prescriptions have to be based largely on biologically-informed theory – theory instructed by, as Chris puts it, “circumstantial evidence.”

The “Eat What We Are” Argument

A good first estimate for carb intake comes from the simple precept that we should “eat what we need.” The body’s glucose utilization level, about 600 calories per day, tells us how much we need. The simple prescription, then, would be to eat about 600 calories, or 30% of energy for a slender person, as carbs. Let’s call this intake a “moderate carb” diet.

Evolutionary Arguments

Another place to look for guidance is evolution: what macronutrient ratios has evolution selected for?  Here we do not place much weight on ancestral Paleolithic diets, which varied substantially from place to place and time to time. Rather, we place more weight on animal diets and the composition of mother’s milk.

Both human and animal breast milk is majority-fat, moderate-carb, low-protein. In milk of all species, the carb percentage closely tracks the infant’s glucose needs.

In animal diets, the macronutrient ratios delivered to the body depend on the design of the digestive tract, which transforms the macronutrient content of food. Digestive tracts are generally good at transforming carbs into fat. As a result, after transformation most animals have carb intakes equal to or below their carb needs. In ruminants and foregut fermenters, the transformation of carbs into fats is virtually complete; in hindgut fermenters, it is only partial.

Many animals achieve so many of their calories from bacterial fermentation of dietary carbs that their diets are actually highly “ketogenic” and nearly zero-carb.

Thus, evolutionary considerations suggest:

  • Optimal human carb intake is probably close to or below our glucose utilization of 600 calories per day.
  • Ketogenic diets with substantial calories from short-chain fats are probably healthy.

I find evolutionary logic convincing. Since healthy creatures will generally have more descendants than unhealthy ones, evolution surely selects for health.

The Argument From Palatability

In addition to being healthy, a diet should be tasty – palatable. People should enjoy it and be pleased to eat it.

This has an influence on macronutrient ratios. Fatty animal foods in general have higher caloric density than carb-rich plant foods. Fruits and berries have 200 calories per pound; potatoes and sweet potatoes 300; taro 600; white rice 1300. In contrast, meat often has about 1000 calories per pound; bacon has about 2400. To eat 30% of calories from carbs, while avoiding toxic foods like grains and sugar, requires eating substantially more plant food than animal food.

But people generally find food most palatable when there is a mix of plant and animal foods. Since carbs come exclusively from plant foods (excepting milk), which have lower caloric density, this means a tasty diet inevitably has more fat than carb calories.

The Argument From Toxicity

As we note in the book, plant foods have more toxins than animal foods. This is because they use toxins to poison animals that might eat them, while animals cannot easily poison predators without also poisoning themselves.

Toxins are found in nearly all plant foods. Peter at Hyperlipid has a post today about berry toxins, pointing out that they have a similar biological effect to a pharamaceutical drug, anacetrapib, that raised the death rate in clinical trials. (I note in the comments that the benefits from poisoning gut pathogens and cancer cells might outweigh the damage from direct toxicity. This is why I eat “Neo-Agutak” – cranberries. )

If it’s desirable to avoid toxins, it’s desirable to keep plant food intake down and animal food intake up. Given the low caloric density of most plant foods, that also implies that carb calories will need to be low on an optimal diet.

Plateau Ranges

As Chris notes, we do not define precise optima for each nutrient, but rather suggest “plateau ranges” that achieve all the benefits and none of the toxic effects.

Based on the above reasoning, for carbohydrates, our estimated plateau range is from 10% of energy on the low end (which we recommend for therapeutic ketogenic diets) to 30% on the high end (a “moderate carb” diet in which all the body’s glucose needs are met from diet).

We do suggest specific values of 20% carbs, 15% protein, and 65% fat. These are mid-range values which casual dieters may wish to aim for; even if they miss by 10% of energy on any macronutrient, they will still be in the plateau range.

What Happens If You Deviate From the Optimum?

But if this logic tells us what the optimal carb intake is, it does not tell us how much harm is done by carb intakes different from the optimum.   

Here I agree with Chris that in healthy people, the damage to health from changes in the carb:fat ratio could be very small, as long as the carb sources do not contain appreciable toxins. The body has a great capacity to convert carbs to fat. So long as that transformational capability remains undamaged, a very high-carb diet may be functionally very little different from an optimal diet.

In metabolically damaged people, however, transformations from one macronutrient to another may be impaired. In this case, the body may have very little flexibility in repairing a suboptimal carb:fat ratio.

I thus agree with Chris’s conclusion:

I thus find it very difficult to believe that humans must maintain their diets within a very narrow range of macronutrient ratios. More likely, the human body is extraordinarily flexible and can tolerate a wide range of carbohydrate and fat intakes.

That said, it may well be the case that in modern folks with damaged metabolism, low-carb is the way to go. Indeed, well controlled studies have clearly shown that low-carbohydrate diets are superior to low-fat diets by a multitude of criteria for people with various markers of the metabolic syndrome (references here, here, and here).

Nothing in the book contradicts this conclusion. As an editorial decision, we chose to describe the “perfect” diet for health without spending space discussing imperfect diets. Given that decision, we didn’t need to address whether a 90% carb diet is only marginally worse, or much worse, than a 30% carb diet.

But that is an appropriate topic for discussion on the blog. I’ve begun a “zero-carb dangers” series; perhaps I should do a “high-carb dangers” series too.


Much research will be needed to disentangle the relative contributions of plant toxins and carbohydrate calories to health.

It looks from early evidence that intake of plant toxins may be much more consequential for health than the overall carbohydrate level. This is good news, since selection of low-toxicity foods and preparation methods that detoxify foods may enable big improvements in human health.

Nevertheless, even if most toxins can be removed, there are reasons to believe that a low- to moderate-carb (10% to 30% of calories as carbs) diet will be optimal for human health. Such a diet seems to work well for nearly everyone, even the metabolically damaged; and it produces a tasty diet that is a pleasure to eat. It therefore seems the most prudent recommendation for diet book authors to make. And we stand by it!