Given the void in dietary wisdom due to the ineffectiveness and blunders of “official” dietary advice, there is no shortage of books or diet programs trying to fill that void, many wildly at odds with each other—paleo, Atkins, vegan, vegetarian, high-carb, low-carb, ketogenic, etc.
The U.S. Dietary Guidelines for Americans, the USDA’s MyPlate and food pyramid, and organizations such as the American Heart Association and American Diabetes Association, as well as many of the diet programs in the popular press, I believe, fail to acknowledge several fundamental principles that really need to be addressed in crafting any sort of dietary program. Failure to acknowledge these principles can lead you down some pretty awful dietary dead-ends, just like the low-fat, low-cholesterol diet did that yielded massive obesity, type 2 diabetes, an explosion in autoimmune disease, and other health conditions. Getting it right, on the other hand, can yield magnificent benefits.
So any effort to create a diet that prevents or reverses many (if not most) health conditions, yields weight loss, and allows you to function optimally must acknowledge several basic principles:
A truly healthy diet must be consistent with human adaptation to life on this planet, as dictated by our genetic code.
Imagine you witnessed a lion tearing open the abdomen of a gazelle, then eating its liver, spleen, intestinal tract, and limbs. You are horrified, so you arrange for the lion to only eat broccoli, kale, and blueberries—presumably healthy vegetables and fruit. What will happen to the lion? It would starve, then die in just a few weeks. Likewise, feed a fish like salmon or trout hay that nourishes horses, and the fish would die in short order, also. In other words, every species has a dietary script written into its genetic code, put there over millions of years of adaptation to the environment. Straying off that dietary script can yield some pretty bad consequences, including death.
Humans, too, have a dietary script written into our genetic code. The historical record is clear: While our pre-Homo ancestors (more than 2.5 million years before present) were largely herbivorous and only occasionally opportunistic scavenging carnivores, the Homo species learned how to make tools and weapons, learned how to hunt as a group to take down large animals, ate their organs and brains that led to dramatic enlargement of the human brain, developed a forebrain that allowed planning and a speech center to allow communication, and we developed the apparatus that allows speech (fine control over the vocal cords, tongue, lips for articulation). As our brains enlarged and required more energy, our colons shortened, as we consumed less fibrous plant matter. Our small intestines lengthened to accommodate the increased consumption of animal products. In other words, the story of human adaptation is unique in that we are the only species that evolved to become adept hunters with brains, speech, and gastrointestinal anatomy to accommodate this lifestyle.
Accordingly, there is no such thing as a vegan or vegetarian population in the wild. We are, at our genetic and adaptive core, programmed to be hunters as well as gatherers.
A healthy diet must be consistent with human physiology
In other words, foods should not exert inappropriate or harmful physiological effects. One example would be extreme and repetitive intake of sugar, as in soft drinks, that generates insulin resistance, small LDL particles that lead to heart disease, glycation of proteins that accelerates aging, and ascending dysbiosis or small intestinal bacterial overgrowth. Another would be the seeds of grasses–grains–that contain gastrointestinal toxins such as wheat germ agglutinin and gliadin; nutrient-binding phytates that make iron, zinc, magnesium, and calcium unavailable for absorption; and amylopectin A that is rapidly degraded to sugar by the enzyme amylase in the mouth, leading to tooth decay.
Healthy foods should provide nutrition without extracting a major health price.
A healthy diet should not require nutritional supplements to compensate for deficiencies
Vegans and vegetarians, for example, are virtually all deficient in vitamin B12 because all B12 comes from animal products. They are also deficient in omega-3 fatty acids (EPA and DHA, not linolenic acid which cannot yield sufficient DHA to prevent, for instance, dementia), vitamin K2, zinc, and often iron. Raw vegans and people who severely restrict fat intake also typically become deficient in fat-soluble vitamins A, D, and E, explaining the tooth loss and bone thinning that can develop, as well as the incessant hunger from inadequate fat intake and inefficient absorption of nutrients from failure to cook some foods. People who consume grains commonly develop deficiencies of iron, zinc, and magnesium due to phytates.
(In the Wheat Belly and Undoctored lifestyles, we do add nutritional supplements, but not to compensate for deficiencies of the diet. We supplement to address deficiencies of modern life such as vitamin D due to leading indoor lives, wearing clothes, and migrating away from the equator, or magnesium because it is filtered out by modern water filtration, or omega-3 fatty acids because fish consumption is complicated by mercury content and most modern people are (unlike our ancestors) averse to consuming brains, iodine because we don’t want to consume the thyroid gland of animals we kill.)
A healthy diet must help maintain healthy bowel flora and supply fibers that yield intestinal butyrate
People who follow a ketogenic diet without addressing prebiotic fibers risk violating this principle. Failure to consume prebiotic fibers leads over time to constipation, dysbiosis and small intestinal bacterial overgrowth, and all the consequences of inadequate butyrate production (by microbes) including higher blood pressure, higher blood insulin and blood sugar, higher triglycerides, depression and anxiety, disrupted sleep and dreams, and increased risk for colon cancer and diverticular disease.
Before you dive into a diet, ask whether you are adhering to these above dietary principles. The lower fat, lower cholesterol diet advocated by the Dietary Guidelines for Americans that favors grains, as you can see, violates several of these principles. Find a diet that conforms to these basic truths of human life and nutrition and you are on your way to enjoying spectacular health and slenderness.