One Food System to Cure Us All? I Don’t Think So.

You can blame or credit NonEntity for this ramble, as you will ... his post’s links triggered S.E.S.S. flashbacks, which Lila recently revived.

Perhaps it is not my place to challenge Dr. McDougall, a “physician and nutrition expert”; it may be unfair to critique his approach based only on the first chapter of his book. I obviously don’t think so: he has posted that chapter ostensibly inviting critical feedback, and certainly to help market the book; and anyone with a basic science background and the willingness to invest a little critical thinking while reading it could find problematic assertions. I’ll quote bits from the chapter, then offer my observations.

Most disturbing is that nearly everyone believes starches are fattening and nutritionally inferior foods. Fortunately, common knowledge is completely wrong and the proof is right before your own eyes.

The most important evidence supporting my claim that the natural human diet is based on starches is a simple observation that you can easily validate for yourself: All large populations of trim, healthy people, throughout verifiable human history, have obtained the bulk of their calories from starch. Examples of once thriving people include Japanese, Chinese, and other Asians eating sweet potatoes, buckwheat, and/or rice, Incas in South America eating potatoes, Mayans and Aztecs in Central America eating corn, and Egyptians in the Middle East eating wheat. There have been only a few small isolated populations of primitive people, such as the Arctic Eskimos, living at the extremes of the environment, who have eaten otherwise. Therefore, scientific documentation of what people have eaten over the past thirteen thousand years convincingly supports my claim. [all emphasis mine]

Is being trim necessarily healthy? It doesn’t seem so to me ... but part of the difficulty is defining trim. For some, trim means something akin to anorexia in my eyes; others may think in terms of good muscle definition, irrespective of fat stores. By placing the adjective there, I can’t help but wonder if McDougall is trying to smuggle some implicit ideas into his plan. Similarly, the loaded adjectives and adverbs prefacing the counterexample strongly encourage one to disregard it. True, it may well be an outlier, but it is nonetheless proof that for at least some individuals, his starch-heavy diet is not the path to better health.

Based on our anatomy and physiology experts have long concluded that primates, including humans, are designed to eat a diet consisting mostly of plant foods. The natural diet of chimpanzees, our closest relative, is nearly pure vegetarian in composition; made up largely of fruits; and in the dry seasons when fruit is scarce, they eat tree seeds, flowers, soft pith, and bark; with termites and small mammals making an insignificant contribution to their nutrition all year long.

“Plant foods” is not the same thing as starches. Lettuces, broccoli, and many other plant foods do not contain starch.

And what exactly does “insignificant” mean? My guess is that he means those protein sources are a relatively small portion of their diet, proportionally speaking. That does not mean, however, that they are unimportant! An organism may need only small amounts of some substance or food group to maintain itself: but it remains vital to living; and more of it might be optimal. Protein and fat are both vital to our health.

Recently, scientists have proven through genetic testing that we are designed to thrive best on one category of plant food known as starch. Human and chimp DNA is roughly 99% identical, but that 1% difference, which includes genes to digest much more starch, proved crucial for the evolution of humanity’s earliest ancestors. Examination of the number of copies of the gene for the synthesis of the starch-digesting enzyme, amylase, has found an average of 6 copies in humans, compared to only 2 copies of this gene in other primates. This genetic difference results in the production of 6 to 8 times higher levels of starch-digesting enzymes in human saliva.

More ≠ better. Couldn’t this finding simply mean that we have more variety in the way our bodies can break starches down?

People should be thought of as “starch-eaters;” just like cats are “meat-eaters.” Until recently, except for a small number of wealthy aristocrats, members of the human species have obtained the bulk of their calories from starch. After the mid 1800s with the creation of colossal wealth during the industrial revolution and the harnessing of fossil fuels, millions, and then billions, of people were able to eat from a table piled high with meat, fowl, and dairy, once available only to royalty. Look around you—the consequences are obvious—everyday people appear rotund like the kings and queens pictured in old paintings. Look a little further and you will discover the Starch Solution.

Look a little more critically and you will realize that many other things changed, along with diet. Royalty not only had a wider variety of foods and more of them, they probably also tended to be less active, as they didn’t need to work hard to support themselves.

The Industrial Revolution changed the way many people work; even those who worked in factories possibly expended fewer calories doing so than they did working a farm or ranch—and that trend has accelerated as machines have increasingly taken over the manual labor elements of production. Even leisure pursuits changed—instead of pursuing sports or even playing a musical instrument and singing, people started sitting and listening to the radio, and later, watching television. In recent years, that trend toward lower energy expenditures has been coupled not with decreasing caloric intake, but increasing intake. Also, the trend toward manufactured and processed foods has shifted our nutritional profile.

[T]he human body efficiently regulates carbohydrates from starches, burning them off, rather than storing them, when consumed in excess. How effective is our body’s regulation? Obesity has been unknown among billions of Asians with a wide variety of activity levels who have followed traditional diets based on rice. However, these people’s immunity immediately disappears when they switch to meals based on meat and dairy foods, because the human body unsuccessfully balances for excess fat consumption—storing these calories in the abdomen, buttocks, and thighs. The fat you eat is the fat you wear. [emphasis mine]

How does that “wide variety of activity levels” compare with an average American’s activity levels? How do the diets compare? Does their immunity really immediately, completely disappear? I’d bet the Asians are mostly eating whole grain, unprocessed starches—a far cry from Doritos, Krispy Kremes, and the like. Such details are vitally important, but McDougall’s words completely glosses them over.

And his last sentence there is pure fear-mongering. That may be true of excess fat, especially if one has a largely sedentary lifestyle, but fats are vitally important for proper nervous system development and maintenance—and that includes the brain. Starve the body of fat and one is starving his brain of its basic building blocks. And again, the type of fat matters: many processed oils take unnatural forms that may be problematic for our bodies to digest and use.

Starches are very low in fat (1% to 8% of their calories), contain no cholesterol, do not grow human pathogens, like salmonella, E. Coli, and “mad cow” prions, and do not store poisonous chemicals, like DDT and methyl mercury. Outside surface contamination, for example, from cow dung and pesticide sprays, may occur, but that is not a fault with the plants. Starch is clean fuel.

More fear-mongering. Raw milk is more healthful than pasteurized, for most healthy people (even lactose-intolerant people may be able to digest it, since it contains lactase; I understand lactase is destroyed by the heat of pasteurization). It is largely the processing and prettifying of foods that create these troubles, not the cows or pigs or plants themselves. Agribusiness mostly focuses on volume and appearance, rather than wholesomeness and naturalness.

I could continue in this vein, but that’s probably more than enough. McDougall does take on agribusiness and other industry influences, but only after subtly biasing the reader toward his system. And more importantly, his genetic evidence seems stuck in time: since mankind evolved, then slowly spread across the planet, our genes have continued to change. The issue of lactose intolerance is one area that demonstrates this: studies suggest lactose intolerance may be linked to ancestral environment. Those lines may have been somewhat clear up to just a few hundred years ago, when global travel started to become more feasible than previously; but today genetic mixing is much more likely, especially in the United States. Will a Scandinavian-Egyptian-Russian-Irish-American be able to digest dairy or not? I don’t know that current science can successfully and relatively inexpensively predict the answer to such a question.

It seems to me that Dr. McDougall’s efforts primarily lie in selling another book, along with more of his packaged foods and stays at his health and medical center. I have no problem with the man wanting to earn a living; but I do have serious problems with attempting to skew science and scaring people into buying stuff.

My research on fasting showed that a normally-functioning human body has multiple ways of handling food. A modest exploration of “expert” opinions reveals numerous divergent recommendations and prohibitions. Rather than allow yourself to buy any system hook, line, and sinker, exercise common sense and skepticism in evaluating it. If you still want to try one, approach it rationally and with a wary eye on your wallet: any system that requires one to buy the guru’s products should be immediately suspect. Rather, try it on your own terms, with items that you would normally buy or grow, or with minimal changes (e.g., raw oats or nuts for processed ones).

Humans have survived millennia by enjoying a wide variety of foods, mostly in moderation and while getting sufficient exercise to benefit their bodies as well. Any system that promotes one type of food and the near-exclusion of another, requires bizarre artificial distinctions or separations that aren’t natural (such as the Zone diet’s phobia of a certain acid found in egg yolks [update: it is arachidonic acid], as well as other foods), or requires constant, careful measuring and monitoring is likely to be more trouble than it’s worth. Minimize the packaged and processed stuff, and then relax and enjoy your meals. The decrease in stress alone will be worth it.