Humans have been evolving for about two million years (two thousand millennia). Our brains have grown in size and function, enabling us to survive ever more by our ability to plan and less by physical prowess. Our communities have been ravaged repeatedly by infectious diseases and our immune systems have evolved to defend us against millions of strains of potentially harmful microorganisms. And throughout these two thousand millennia of evolution humans have survived on a relatively consistent diet of leaves, stalks, and bark, berries from bushes, wild grasses (all sources of fiber), whatever animals we could kill (protein and fat), nuts and seeds (fat, protein, plus some fiber and carbohydrates), flowers, roots, and the occasional fruits and vegetables available during warm seasons (fiber and carbohydrates). During this protracted period, the human digestive tract evolved to accommodate to this diet, which was rich in antioxidants, high in fiber, moderate in protein, and relatively low in fat and sugar (carbs). I call this diet the Human Diet. Very carbohydrate-dense foods like tropical fruits and sugarcane were not part of the Human Diet (with the exception of tiny populations of peoples living near the equator) and did not make their way into wider consumption until very recently in the history of our species. Even grains such as wheat and rice, which, like tropical fruits, contain very high levels of carbohydrates, were not incorporated into the Human Diet until about 10,000 years ago–a short time from an evolutionary standpoint, and, as will be discussed below, those grains bore little resemblance to the ultra carb-dense, genetically modified versions which have come to dominate the commercial food market over the last 50-60 years. Perhaps the most important point I hope to make here is that for about two million years humans evolved alongside a diet that kept blood sugar relatively stable because our food did not contain carbohydrate dense substances like bran muffins, apple juice, and candy bars.
Evolution is an extremely slow and incremental process. It takes hundreds of generations for a species to adapt biologically to an environmental shift as radical as the recent changes in the typical American diet. The Human Diet to which we are evolutionarily adapted is the nutritional blueprint from which our bodies have learned to extract maximal nutrition and digest food with the least amount of stress. It is the diet that best enables us to develop properly, grow strong well-balanced immune systems, and live long healthy lives. The Human Diet offers us the best chance to avoid becoming obese and developing chronic diseases like hypertension, diabetes, and atherosclerosis which are now epidemic and quite literally ruining the health of our bodies and our economy.
In the last 50-60 years breakthroughs in the fields of biochemistry, engineering, and genetics have been applied to the manufacturing of fertilizers, insecticides, and crop breeding; this has utterly changed farming and has led to the introduction of new food substances into today’s typical American diet (TAD). Many of these new foods are fundamentally nutritionally different from those to which we are evolutionarily well-adapted. They contain proteins to which we have never been exposed, synthetic hormones, germicidal chemicals, and substances not found in anywhere in nature. Perhaps most pernicious of all, today’s food supply is dominated by carb-dense foods which cause blood sugar levels to soar. Research over the last 25-30 years has shown conclusively that consumption of carbohydrate dense foods (CDFs) provokes unprecedented escalations in blood sugar, and that these blood sugar spikes are responsible for the inflammatory changes that lead to obesity, illness, and drive the aging process. We now know that regular consumption of CDFs is the controllable behavior chiefly responsible for obesity and chronic diseases. The prevalence of CDFs in the TAD (typical American diet), more than any other single factor, is the cause of our current health and healthcare crises.
Read Part 3 of this series: Carbohydrate Dense Foods (CDF's)