Rather, diets would have varied by geographic locale, climate, and specific ecologic niche.However, there are universal characteristics of preagricultural hominin diets that are useful in understanding how the current Western diet may predispose modern populations to chronic disease.

Additionally, mixtures of foods listed in Table 1 make up the ubiquitous processed foods (eg, cookies, cake, bakery foods, breakfast cereals, bagels, rolls, muffins, crackers, chips, snack foods, pizza, soft drinks, candy, ice cream, condiments, and salad dressings) that dominate the typical US diet.

Hominins, like all mammals, would have consumed the milk of their own species during the suckling period.

When the environment remains relatively constant, stabilizing selection tends to maintain genetic traits that represent the optimal average for a population (2).

When environmental conditions permanently change, evolutionary discordance arises between a species’ genome and its environment, and stabilizing selection is replaced by directional selection, moving the average population genome to a new set point (1, 2).

Osteoporotic hip fractures are associated with a 20% excess mortality in the year after fracture (17).

Cancer is the second leading cause of death (25% of all deaths) in the United States, and an estimated one-third of all cancer deaths are due to nutritional factors, including obesity (18). Similar to historically studied hunter-gatherers (20, 21), there would have been no single universal diet consumed by all extinct hominin species.

Hence, as was the case with dairy foods, before the Epi-Paleolithic (10000–11000 y ago) and Neolithic (10000 to 5500 y ago) periods, there was little or no previous evolutionary experience for cereal grain consumption throughout hominin evolution.

In Table 1, it is shown that 85.3% of the cereals consumed in the current US diet are highly processed refined grains.

Sixty-five percent of adults aged ≥20 y in the United States are either overweight or obese (13), and the estimated number of deaths ascribable to obesity is 280184 per year (14).