In many ways, what we are doing in following the arguments in Wheat Belly is returning to the ways of primitive humans.
Humans have adapted to life on earth under a range of conditions, from sub-Arctic cold coastal conditions, to hot dry African Savannah conditions, to wet tropical conditions. Over this 2.4 million year timeline of adaptation, our bodies have become dependent on a number of nutrients, many of which we no longer obtain in sufficient quantities. We also have more recently incorporated foods into our diet that were not present during the majority of time that humans have walked the earth. Among the most important:
—Wheat and other grains–Despite the wide variation in foods and environmental conditions that Homo species have survived under, there is one constant: NONE ate grains. Some ate fish, virtually all ate the organs and meat of land creatures (mammalian and otherwise), insects, each other (i.e., cannibalism), nuts, seeds, tubers/roots, fruit, and other edible parts of plants–but NONE ate grains. None ate grains until approximately 10,000 years ago: einkorn and emmer wheat in the Fertile Crescent, maize/teosinte in Meso and coastal South America, rice from the swamps of Asia, sorghum and millet in sub-Saharan Africa. We have therefore consumed grains for 0.4% of the time we have inhabited earth (with a subsequent downturn in health as a result).
—Omega-3 fatty acids–Primitive humans ate the brains and other organs of animals that contained the EPA and DHA required for human brain and overall health. They also consumed marine creatures, if coastal. This was among the driving factors believed to have contributed to the 300% in brain size experienced by Homo, from the 450 cc brain of Australopithecus to the 1350 cc brains of modern Homo sapiens. (Though omega-3 fatty acid consumption alone is insufficient by itself to fuel brain size, else lions and jackals would be the smartest creatures on earth.) This is why fish oil, containing highly-concentrated EPA and DHA, provides unexpected and broad health benefits. You could, of course, eat the brains of animals, but fish oil capsules and liquid is more convenient and palatable to most.
—Vitamin D—Homo lived outdoors, often with substantial skin surface area exposed, the phenomenon that generates vitamin D, crucial to overall health. As humans migrated to climates away from the equator with less intense sunlight and greater need for heat-protective clothing, we lost our dark skin coloring to make us more sensitive to the ultraviolet light required for the vitamin D reaction. The most northern humans, such as the Inuit, lost their melanin coloring but also consumed the organs of animals, especially the liver and kidneys, rich in vitamin D.
—Vitamin C–Unlike most other mammals, humans do not synthesize their own vitamin C, required for numerous bodily reactions. So we obtain vitamin C by consuming the liver and kidney of animals, as well as fruits and vegetables.
—Iodine–Iodine is the primordial antibacterial. Just as Mom swabbed it on your knee when you skinned it, so your salivary glands, mammary glands, and thyroid have come to rely on iodine. Your thyroid gland requires it to produce the thyroid hormones, T4 and T3, with T4 requiring 4 iodine atoms per T4 molecule, T3 requiring 3. We obtained iodine by consuming marine animals and plants, or by consuming animals and plants that contained iodine that had leached into or was residual in the soil from the ocean.
Human needs extend beyond these factors, of course. But these factors–no grains, omega-3 fatty acids, vitamin D, vitamin C, and iodine–are among the most powerful of strategies to adopt into modern human diet and health. It also provides an explanation for why, when us modern humans adopt such practices, a multitude of health benefits develop.