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!

Leave a comment ?


  1. In wild animal diets, is the macronutrient composition in any way analogous to that of the adult’s diet? I honestly don’t know and that would be interesting to investigate.

    I dunno, if I were writing a “paleo” book I wouldn’t deal with macronutrient percentages at all because there is no way of knowing our evolutionary heritage in that respect, besides some bone isotope studies that show protein was high in some populations, but that doesn’t say anything about percentage.

    Biological sciences can show us some toxic upper limit and a lower limit, but between that who knows what’s optimal?

    I do think long-term practitioners of evolutionary nutrition will end up with a ratio similar to yours, but not intentionally by looking at ratios or anything, just because that’s how the diet ends up looking.

    I’d definitely like a series on a high-carb not-insane diet . I don’t think many paleo practitioners have done it (the 30 bananas a day people don’t count, though some of them report doing fine), but I might try it at some point. I would do mostly yams, potatoes, cassava, taro, plaintains, and cocoyam. The dude Stephan blogged about who ate only potatoes for a month was interesting, but the guy was coming from a SAD diet. It would be interesting to see what happens to me coming from a relatively low carb diet.

    As you said, the main problem would probably be that the plant toxin level would be very high.

  2. Hi Melissa,

    Re wild animal diets, the main point is that the structure, metabolism, and biology of cells is very similar in all animal species … and so their macronutrient needs are very similar.

    Mammals all have the same parts list, and essentially the same set of genes and the same cellular biology, so when the same macronutrient ratio keeps getting selected over and over again in all mammalian species, that says something to me.

    Especially since these mammals eat a wide range of foods, and have had to evolve big changes to their digestive tracts in order to get the macronutrition reaching their bodies back to the evolutionarily preferred ratios.

    We do have a section in the back of our book on how to design a healthy vegetarian diet. That is a high-carb diet. The key is to get toxin levels down and key nutrient levels up. Supplementation and/or eating eggs are highly desirable.

    Best, Paul

  3. Paul,

    For what it’s worth, I thought most of the above points came across well in your book, no clarification needed for me.

    Another argument from palatability could be based on observation of the common features of the favorite dinner meals from the many different cultures around the world. It seems that in many different cultures, when people have the money and means to choose a tasty meal from foods that are naturally available, they choose a plate that has: a fatty meat or lean meat with added fat, a starch, spices, and a side of vegetables. This leaves room for variety in the exact macronutrient ratio of course, but it does suggest a basic formula for what humans like to eat if given a choice.

  4. Why would the composition of mother’s milk be ideal for an adult? I realize Jan Kwasniewski purported to use mother’s milk composition as his model (although I think some have questioned the accuracy of his ratios) for adult nutrition but couldn’t one argue that mother’s milk is ideal for babies and not adults?

    I’m a very long-time low-carber (very low carb paleo other than butter) and I look forward to reading your book. I am not interested in losing weight — I’m thin thanks to low carb — just always interested in maximizing health.

  5. Hi Annie,

    Yes, mother’s milk is optimal for infants not adults, which calls for some adjustment.

    The biology is similar, but infants have big brains and small bodies, so their glucose needs are higher. Thus, human breast milk is almost 40% carbs and this would be too high for an adult. If you adjust for brain glucose consumption, you get an estimated optimum for adults closer to 20%.

    Best, Paul

  6. I’m in agreement with Melissa in that beyond perhaps some upper and lower limits for macronutrient intake, we really have little way of knowing what is optimal, if indeed a single optimal number exists. I truly believe the issue is a qualitative rather than quantitative one and we can see this illustrated very clearly in the differences between PUFA and SFA fatty acids (a point made very well in the book). No doubt, the same holds true for carbohydrate. Paul points to the toxic effects of fructose (a carbohydrate) in the book – versus glucose.

    When people put it all into practice and begin to cut out predominantly grain-based and fructose-based carbohydrates, yes they reduce their carbohydrate quantity, but they also have some scope (in some cases) to increase carbohydrates sourced from starchy root vegetables and the like. As Melissa mentioned, we have a few examples of this coming through that we need to work through the mechanics of.

    As a nutritionist at the coal face, people are hopeless with trying to eat based on numbers, be they calories, grams of CHO, etc. Eating by numbers is not particularly intuitive for anyone and makes eating a very tediuous affair indeed. The Perfect Health Diet approach (whilst containing numbers that are useful to know for practitioners) can be translated and fine-tuned into quite a nice qualitative plan that suits most people.

  7. Hi Jamie,

    I didn’t know you work at a coal face! I assume you just mean with the general public …

    Thanks for your praise for our diet. Yes, I think just knowing that you don’t need to be scared of fats, can pair starches with fats, eat fatty meats, and limit grains but include rice, potatoes, fruits and berries, will get almost anyone to a good macronutrient ratio.

    Melissa, I may have misunderstood your comment. I completely agree that no one should have to count calories as a routine activity. It is natural to eat well, and should feel that way.

    For me, if I had to eat a very high-carb diet, white rice would be a big part of it. I am not convinced that huge amounts of fiber are desirable.

    Best, Paul

  8. Paul,

    I agree with Todd that your intent came across clearly in the book.

    Furthermore, I found the recommended ranges very useful. Since I was coming from the low carb side of the fence, the main effect the book had on my diet was to motivate me to increase my starch intake (mainly from rice). On the other hand, the discussion about how the body deals with excess glucose raised enough concerns that I am not inclined to go above the high end of the recommended range, even if I found this much starch palatable. But unless the starch is accompanied with a lot of fat or a significant amount of sugar, I don’t find it very enticing.


  9. I am interested to know what you think about body composition and exercise tolerance in overall health. The people I know with the greatest body compositions (low-body fat and great musculature) all eat relatively higher protein diets, with some eating very high carb, and others eating moderate carb and moderate fat. However, the trend I notice with all of these is a low fructose consumption. Some of the leanest I know of eat only green vegetables b/c of concern over fructose, or only consume fruit post-workout. Another trend is that they rely on oatmeal, sweet potatoes, and brown rice for carbs…and maybe pure glucose or maltodextrin post workout.

    This leads me to believe that overall fructose, along with gluten is likely a factor in obesity, and beyond that, presuming one is getting their EFAs in somehow, they will be healthy.

    It actually makes me think that wonder as one gets closer to the essentials…glucose (in whatever form so long as it does not contain gluten and/or sugar/fructose), EFAs, and essential amino acids, the healthier they are. I have noticed that the more I focus on “health” by eating a wider variety of veggies and more fruits, the worse I feel. Maybe it’s just me, but it does make me wonder. Have you ever heard of people just “eating clean.” THis is where they eat mostly lean proteins, nuts, green veggies, some fruit, and starches like brown rice, sweet potatoes, and oatmeal. These people are consistently the leanest and fittest (judging by exercise tolerance). So, how does this relate.

    IT seems that fructose, sugar, and gluten are the real culprits…as well as the obvious trans fats and a diet high in omega-6s with inadequate omega-3s.

    What’s your take on this?

    Love the blog, and keep up the good work!

  10. …Like for instance, look at Dara Torres. She “eats clean” and maintains a very high level of athleticism. Also, look at the diets that people like Ryan Reynolds, Daniel Craig, Taylor Lautner follow to get in shape for movie roles. They are all high protein, moderate carb, moderate fat diets which include mostly the same foods…brown rice, sweet potatoes, oatmeal, limited fruit, nuts, olive oil, greens, chicken breast, fish, and fish oil supplements and whey protein supplements, eggs/egg whites. A trend is, again, LOW FRUCTOSE and LOW GLUTEN and relatively low plant matter (by stickign mostly to the plants that give glucose and then some greens for antioxidants/general health, presumably).

  11. Hi Nelson,

    Protein suppresses appetite and is helpful in achieving an extreme cut/lean look for bodybuilding competitions. However, high protein intake is neither particularly healthy nor is it necessary for adding muscle. Excess calorie intake is what builds muscle, as long as protein is adequate adding fat or carbs will work just as well in promoting muscle synthesis.

    I would not idolize extreme leanness.

    Yes, toxins are probably the major factor in obesity.

    You shouldn’t focus on “essential” amino or fatty acids. Just get whole food proportions. “Essential” does not mean more desirable than “non-essential.”

    Your “eating clean” sounds like a calorie restricted diet. Again, that is good for achieving leanness for a bodybuilding competition or a movie, or for losing weight rapidly. It is not an optimal long-term diet.

    Best, Paul

  12. I guess I’m just confused. What’s best for optimal body comp also seems best for optimal performace. For instance, look at what the best cross-fit athletes (perhaps the most encompassing sport) eat. Lots of them are what would be termed zone-paleo, which is 40%C, 30%P, 30%F. With the top ones always emphasizing proteins. So I’m a bit confused still. Are these athletes missing something as well? I don’t really understand. Thanks for your help.

  13. Hi Nelson,

    There are some hormonal effects of protein which are not all that well understood. In insects, high protein diets stimulate libido, fertility, and reproduction, at the cost of shortening lifespan. They also reduce appetite.

    Similar effects, including appetite reduction, have been observed in humans. It’s possible that high protein may stimulate some aspects of athleticism in humans. Protein also probably shortens lifespan.

    But whatever protein’s effects are, they’re fairly minor. In studies of athletes, once you reach ~1 g/kg/day protein, there’s no discernible increase in muscle synthesis from protein if total calories are held constant.

    However, high calorie intake is very effective in promoting muscle synthesis. So additional calories from any source, be it carb, protein, or fat, will promote muscle synthesis.

    So there’s no need to get 30% of calories from protein. 15% of calories is plenty.

  14. Paul,

    I agree with those above who felt the book explained your points well. Since it’s New Year’s resolution time, some questions-

    What dietary patterns do you recommend for those who want to reduce their energy intake for weight loss?

    What do you recommend for exercise, for optimal health?

    I know you mention some lifestyle aspects in the book, but do you have any other speculations on lifestyle changes for “perfect health”?

    Thanks again!

  15. Hi Robert,

    For weight loss I favor ketogenic type diets – so 200 carb calories, 400 protein calories to get to the minimum 600 carb+protein – plus some coconut oil with fat making up the remaining calories. Choose your calorie target – for men 2000 calories/day might be good, for women maybe 1500 – and choose foods accordingly. Supplement for good nutrition. Be sure to get egg yolks for choline (3 egg yolks a day may be a good rule). Favor salmon/beef/lamb in order to get omega-3 and keep omega-6 down; favor butter and coconut oil among oils. I would also do intermittent fasting, restrict food to an 8-hour window each day.

    I do have ideas about exercise and lifestyle, but I don’t consider myself a fitness guru by any means.

    For exercise I would suggest being on your feet as much as possible. A “standing desk” would be better than a sitting desk. Take the stairs rather than the elevator. Try to walk regularly. Resistance exercises for strength are good twice a week; leave a couple rest days between each workout. Running, push-ups, pull-ups, rowing, dips, and squats are basic exercises. Mobility & posture exercises I think are also helpful – especially for the shoulders if you work on a computer all day.

    I might start blogging about what I do next year, but I have a big backlog of other interesting post ideas!

    Best, Paul

  16. Thanks for clearing that up. I have think that you hit the nail on the head…at the cost of decreasing lifespan. I worry that frequent insulin secretion is the cause of many of our ills. That comes 1) too high consumption of carbohydrate, 2) too high of consumption of carbohydrate. I am unsure about which is easier on the pancreas though. One can either consume many small meals throughout the day (which is what most athletes practice now-a-days…often 6, but sometimes up to 8 or 10 times a day) or once can consume fewer, larger meals. I wonder which is harder on the pancreas and which, overall, would stimulate more insulin secretion? I think that four, decent meals per day for the athlete seems optimal to me. A breakfast (more carbo dense), 2 afternoon meals (with plenty of healthy fats), and a balanced and satiating evening meal with maybe a glass of wine or fruit for desert. I think this seems Ideal. For instance, a breakfast of some safe starch and protein/fat, 2 afternoon salads with fruit and nuts, and maybe some leaner meat, and an evening meal with a starch and a fatty protein. I don’t know why, but four seems like a good compromise to me. What are your thoughts? I just want to know the best way to simultaneously increase longevity and performance. I almost think that the kitavans have the ultimate ideal diet for the athlete. It consists of plenty of carbs, low fat, and low protein. If the athlete just supplemented the current kitavan diet with some form of an amino acid mixture, I think it would perhaps be the most ideal athlete diet. The coconut oil (MCTS), tubers, and fruit ALL supply energy to the muscles AND brain, and are ALL protein sparing. THe low fat minimizes excess bodyfat while on a high carb diet. Also, sicne the protein is fish, there are sufficient EFAs for health. Nothing extraneous for the athlete. OH, and greens provide antioxidants or whatever benefits there are to consuming foods high in oxalates (there must be some, since all cultures love their wine, chocolate, and green leafy vegetables of some sort…all high in oxalates).

    PS- I realize there’s a lot in these posts…but I just want to know all! I was an economics major at ST Lawrence University, but now, I am considering probably switching to biology (like my father…a pediatric anesthesiologist), because I want to learn all and write about the optimal diet for humans…JUST LIKE YOU!

    THanks so much for all of your help. BTW, Today, my macros hit 50%fat, 25%carbs, and 25% protein. Protein came from sardines, yogurt, chicken, and cheese, and fat came from grass fed dairy sources, fish, almonds, and a little bit of dark chocolate. Carbs were from banana, sweet potato, and spaghetti squash. I also had spinach and bell pepper and mushrooms as veggies…oh, and real, raw sauerkraut. Now I’m enjoying a glass of red with a movie/writing. I was going to use coconut oil instead of cheese with dinner for some fat, but I read today about dairy fat and 1) rickets and 2) diabetes prevention…so I went all out on the dairy. Hahah. Tomorrow, I’ll switch to coconut. I also want to try the cranberry/coconut/spinach fast and the pure coconut fast. THe pure coconut oil fast seems like a great cleanse. I would just add in my probiotic supplement (which may be a waste of money, idk) and my raw kimchi or sauerkraut. I think that would be ideal. Maybe some free form aminos post workout, but i think not.

    Oh, if you could find the questions in here and answer them, that’d be great! Again, thanks for helping us attain optimal health with yoU!!

    . I really appreciate all you guys are doing, and I love the economics inspired posts! Keep up the good work! I

  17. OH, also, why are the “toxins” in grains and legumes considered “toxic”, but those in vegetables and fruits (like oxalates) not considered toxic. Shouldn’t spinach and berries (two foods you condone) be considered HIGHLY TOXIC because of this. Why isn’t the optimal diet one that provides all the essentials with nothing else. That is, why doesn’t the optimal diet include only monounsatured (which does not seem to promote insulin reisitance and may increase HDL and omega-3s..i.e. olive oil, almonds, and fish) and only low toxicity sources of glucose and only sat-fat free/lean protein. It seems to me like the optimal diet should be very low in plant matter in general, and only get what is necessary. THe most nutrient dense sources are probably sweet potatoes. Fruit is unnecessary, so can eliminated. Get vitamin c from lemon juice squeezed atop fish for protein. Aren’t all plants filled with toxins, so why should we eat any at all beyond what’s imperative for 100gs glucose? THen, after that, just eat a bunch of meat (which would necessitate a fairly high protein content in the diet).

  18. If you want to stay in the author biz, and I hope you will, you can’t say “… called my wife and I …”. You have to say ” … called my wife and me …”. Sorry.

    Once again (see my comment on your review of Art De Vany’s book) I refer you to this New Yorker cartoon.

  19. Steve – I know that, but this blogging business seems to short-circuit my grammar neurons. Perhaps I should enlist you as an editor? Or at least post that cartoon on my computer.

    Nelson – All toxins are toxic, but not all produce very harmful effects in humans. Sometimes they produce more toxic effects to gut pathogens than to the human host, and this is beneficial overall.

    I’m not a fan of perpetual small meals, I personally practice intermittent fasting which is usually a 16-18 hour fast each day, so concentrated eating in the remaining 6-8 hours.

    I’ll look forward to your entry to the diet authoring business! Be sure to watch your grammar!

  20. Hi, Paul,

    No questions for now, but found this blog via Chris’ review (and bought the book on his recommendation…can’t wait for Amazon to deliver.)

    It is an exciting time, with some great minds taking to the blogosphere to bring science to nutrition…a field that has seemed rather science-resistant until recently.

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

    I disagree, I think it is easy to find the proper amount of carbs to eat. Eat the amount of carbs that keeps your fasting insulin level at 5 or below. (You can order the test yourself from Direct Labs for $29)

    That amount of carbs will vary greatly between individuals.

  22. Hi Jake,

    I would agree that minimizing fasting insulin is a good strategy, although you could argue for minimizing HbA1c (a glucose measure).

    Do you know of any sources for the distribution of carb intakes across persons which produce minimal fasting insulin? I assume your last statement is based on anecdote. I would be very interested in learning more.

    Best, Paul

  23. Saturated and monounsaturated fats. These are benign at all intake levels: non-toxic in high doses, …

    Since reading Chris Masterjohn’s series on choline [1] I think it’s a little more nuanced: saturated and monounsaturated fats are benign only when your diet contains enough choline (which the Perfect Health Diet does). With too little choline, high amounts of any energy source, including saturated and monounsaturated fats, seem to have the potential of causing your liver to accumulate fat.


    [1] Masterjohn, C. The Sweet Truth About Liver and Egg Yolks, Does Choline Deficiency Contribute to Fatty Liver in Humans, and Meeting the Choline Requirement.

  24. 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 which I believe focuses on protein) 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.

  25. Thank you, Doris! We love to hear that people have benefited from our work!

  26. I loved your book.

    What I keep wondering about is how much of an optimal diet depends on ratios of macronutrients, particular foods to avoid or supplements to include, etc. versus eating a diet of natural foods, regardless of whether it’s plants or animals, low carb or high carb,

  27. Paul — I’m about halfway through the book and finding it extremely informative. (I went ahead and bought the dead-tree version because I just couldn’t wait for a Kindle edition.) I have a question about butter: I have a tendency to high cholesterol (as do my mother and several of my siblings). For that reason, I’ve been using olive oil for cooking and as a condiment. Nothing would please me more than to be able to use butter instead, but should I be worried about its effect on my cholesterol level? TIA

  28. Hi JP, I think butter is good for you. You may have seen news about the recent paper showing that people who eat butter have better blood lipids and lower risk for diabetes.

    Stephan had access to the paper pre-release:

    Best, Paul

  29. Perfect Health Diet » Old Diets, New Knowledge: For Auld Lang Syne - pingback on December 31, 2010 at 9:43 pm
  30. I finished your book just 30 minutes ago- Thank you so much for a fascinating and informative read. Happy New Year and best wishes for 2011!

  31. I just added your very interesting blog to my Bookmarks. Good stuff! Quick question if you don’t mind? You hinted that infants might get problems with over 9% protein. Why is that? One would think that protein is good since they are growing.

    What would the optimal ratios for infants, say a 2 year old, then be?

    Thanks, all the best!

  32. Hi Johan,

    Very little protein is needed to support growth, and protein metabolism releases toxic nitrogen products and stresses the kidney. Infants are not as good at toxin disposal as adults.

    Mother’s milk has 6-7% protein and this is optimal. Formula with 9% protein has been shown to induce obesity and other problems, and may reduce IQ. Some citations in this post:

    We don’t know how optimal protein evolves with age but as children grow they become able to better tolerate protein. I would recommend keeping protein around 6-7% through the traditional ages of weaning (maybe age 3) and around maybe 10% or so through puberty.

    If you let your children eat to taste, you’ll probably find they migrate to fats and carbs and avoid protein. Taste is evolutionarily selected and is usually a pretty reliable guide (but keep them away from fructose).

    Best, Paul

  33. I noticed that my 4 year old daughter seems to perform her own version of protein cycling. She will avoid it for days, then suddenly eat an adult serving of meat, then go back to the rice again.

  34. @Doris

    Hi Doris,

    The Optimal Diet does not focus on protein. It is a low carbohydrate very high fat diet that emphasizes saturated fat. Protein is strictly limited. Carbs are never more than 50ish per day. I too was alarmed by the purported high rates of gastro cancers amongst long-term Optimal Diets. The ratios seem similar to the Perfect Health Diet in terms of limiting carbs and protein while emphasizing fat, especially saturated fat.

  35. Hi Annie,

    We have more considerably more carbs than the Optimal Diet and we believe that should protect against the gastrointestinal cancers.

    We discussed what we think is the cause of GI cancers on the OD here:

    Best, Paul

  36. Thanks for the reply!

    From my experience, my child does “protein cycling” as well like Todd Hargrove noted above: Sometimes she eats the meat and goes easy on the potatoes, sometimes the other way around. Lean meat she’s never really enjoyed. She always loves fat.

    Might not the weight gain with the higher protein intake in Koletzko et al. be muscle and bone?

    Also, are you familiar with MD Tom Brewer’s theory of pre-eclampsia as protein deficiency? ( ) His clinical experience doesn’t seem to support the view of protein being harmful in pregnancy (nor does common sense, since babies are made of loads of protein. Maybe concerns with a too high a protein intake are only valid in a “cordainesque lean meat diet”, one that is deliberately (and un-palatably) very high protein. A normal low-carb diet usually has about the same protein (15-20%)as a standard diet, I believe.

  37. Hi Johan,

    I do believe that malnutrition is one of several factors causing preeclampsia. But I believe it’s micronutrient deficiencies, not protein deficiency, that is at fault.

    Pre-eclampsia is characterized by high rates of protein excretion. Why would the mother’s body excrete so much protein if it had a deficiency?

    Pre-eclampsia appears to be caused by a lack of oxygen to the developing fetus, and feedback effects produce the pre-eclampsia. Angiogenesis inhibition causes pre-eclampsia in animals.

    Magnesium supplementation can prevent it,

    Meanwhile, high protein definitely causes obesity in infants — the weight gain is not muscle and bone. See

    Best, Paul

  38. @Paul

    Thank you for the link. I am awaiting arrival of your book and look forward to reading more details.

    In the iterim, the ox tail broth with its high gelatin content looks delicious.

    Since you have read Peat’s work, what do you make of the fact that he does not beleive that low protein is desirable and that protein deficiency contributes to hormonal dysfunction? From his newsletter and books — he seems to advocate around 90+ grams of protein and more when one is ill or under stress. I believe this amount would be altered depending upon one’s size but still, he is critical of the WHO protein recommendation which he claims was good to prevent malnutrition but far from ideal. Also, his book on nutrition advises against eating greens and virtually all veggies exept potato, carrot and properly prepared corn? He is not an advocate of greens because of their antinutrients and thyrotoxic compounds.

    Re: Mucin: While you believe too little mucin is a potential problem on very low carb, it is curious that not all very low carbers have this issue. Middle age is a common cause of dry eye due to hormone dips. I’m not doubting your personal experience or those of others, but I find it curious that so many people do not experience this. I’ve low-carbed for many years and did not have this dry eye symptom. I am very petite — so perhaps my vitamin c requirements or carbohydrate requirements are lower. Too many berries or even vitamin c irritates my bladder to no end. Of course, that could also be a result of middle age.

  39. Hi Annie,

    We have a fairly broad range of protein intake, from 50 g to 150 g per day.

    It’s fairly clear that within that range there are some trade-offs which everyone has to evaluate for him/her self. In animal and insect studies, higher protein promotes fertility, athleticism, strength and power but shortens lifespan and worsens immunity against intracellular pathogens. So while there is no evidence of acute toxicity or malnutrition in our protein range, there may be significant long-term effects.

    I think that 50g/day protein is sufficient unless one restricts carbs, in which case extra protein is needed for gluconeogenesis.

    Ray is a rich source of offbeat diet advice and most of the time I am unsure whether he is right or wrong but intrigued. As you’ll see when you get our book, we give great weight to avoiding toxic compounds in plant foods, but have no strong recommendations about vegetables — we recommend eating them to taste, since the evidence suggests their health impact is minimal, not clearly positive or negative. Vegetables do contain toxins to humans, but also toxins to gut pathogens and various micronutrients, so it is not obvious how the balance works out. Since toxicity depends on dose, and the greatest nutritional benefit comes from the first bits, a modest consumption of diverse vegetables is most likely to be beneficial.

    The dry eye symptoms probably depend a lot on protein consumption. If your glucose requirements are lower, and you eat sufficient protein to manufacture it, then you may be safe with very low carb diets. I have never been a big protein eater.

    Best, Paul

  40. Hi Paul again,

    this is interesting and serves as a reminder that a LC diet should be high fat, not high protein. Although I’m still not convinced about that protein-adiposity theory… More likely due to difference in formula and breast milk – possibly has to do with milk protein on formula being mostly casein (and no enzymes to digest it) and human milk mostly whey. Also, one of the references in the link was this Danish study in which increased protein caused more IGF-1 which caused bigger body size but not higher body fat (ergo, muscle and bone).

    Strange though, I thought carbohydrates increase IGF-1 at least as much as protein? They don’t discuss this.

    I’ve just ordered your book, look forward to it!

  41. Perfect Health Diet » Experiences, Good and Bad, On the Diet - pingback on January 5, 2011 at 1:09 pm
  42. Hi Paul, do you think that if anyone has a disorder of accumulation of long chain fatty acid should switch to a low fat diet?

  43. Hi snaider,

    What disorder do you have in mind? A genetic disorder?

  44. Hi, I’m referring to a pattern seen in children with autism. I think it doesn’t have genetic cause.

    Here I read this:

  45. Hi snaider,

    That’s an interesting paper, thanks. I’ll have to read it and ponder it, but my first reaction from reading the abstract is that it’s a case for a ketogenic diet.

    Glutamate stress by itself can cause this phospholipid pattern, so it looks like that’s probably the big issue. Ketosis reduces brain glutamate levels and relieves glutamate stress. See this post for more:

    Ketogenic diets are therapeutic for many brain conditions, so I wouldn’t be surprised if they help autism also.

    A pilot study found that ketogenic diets help autistic children:

    There is a discussion of emerging evidence that ketogenic diets help autism in this paper:

    I’ll have to do a blog post on ketogenic diets for autism to get this information into our search index.

    To answer your question directly: No, I think autism calls for a low-carb high-coconut oil diet to create ketosis, not a low-fat diet.

    Best, Paul

  46. Thanks.

    I’ll be glad if you do some posts about autism!

  47. Hi Paul.
    this morning I started the day with a tablespoon of coconut oil and some freshly juiced cucumber,celery and a tomato.then had a boiled egg,then some freshly ground white rice porridge with some berries cocoa powder and about 3 big spoons of 1/2 fat Creme fraiche . about 30 mins later i felt quite nauseous and had to have some fresh ginger,after about another 20 mins it subsided but im wondering if im overdoing the fat?

  48. Hi Chris,

    It’s possible, that sounds like a 90% fat breakfast and if the gallbladder/pancreas/stomach aren’t properly coordinated it might cause nausea.

    Another possibility is a dairy sensitivity, another is a challenge digesting small-chain fats in coconut oil which are the most difficult fats to handle.

    You might experiment substituting out the dairy, substituting out the coconut oil, and trying relatively more food and relatively less fat/oil to see what fixes the nausea.

    Best, Paul

  49. Hi Paul, I also get nausea very often…it happens especially when I overdo with fats. Maybe also too much magnesium citrate trigger it.

    When I take copper during day often I wake up during nigh and vomit.

    I vomited very few times in my life but in the last 6 months very often.
    Do you think plant enzyme (low in lipase but high in protease) can trigger nausea?
    If I remeber well I got nausea a month or so after I started them.

    Why do you say that small-chain fats in coconut oil are the most difficult fats to handle? I know they are esier because don’t need bile do digest.


  50. Hi Kratos,

    If copper induces vomiting then you definitely shouldn’t take it!

    Protease enzymes can have complex effects, they can cleave membrane proteins on human cells disrupting their function. I favor enzymes that are rich in carbohydrate/polysaccharide enzymes, if you are going to take supplemental enzymes. It wouldn’t surprise me if proteases could contribute to your vomiting.

    In some ways small chain fats are easier to handle … but they can disrupt cell membranes, which is why they are antimicrobial. I think a lot of people report nausea when eating a lot of coconut oil. I’m not really sure what the mechanism is.

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