Why We Start with an Evolutionary Perspective
HealtyTips - The biomedical database PubMed contains more than 22 million articles, and a million new papers are added each year. A typical scientist reads at most a thousand papers per year. No matter how long a scientist’s career, it’s impossible to read more than 0.1 percent of the literature. Looking at all this research is like looking at a disassembled jigsaw puzzle with no picture of the completed puzzle. It’s hard to tell how to put the pieces together.
Adding to the problem is the complexity of human biology. We need to get many nutrients, maybe hundreds, from our food. Food contains thousands of toxins. With so many different ways food can nourish or harm us and so many different ways to assemble foods into a diet, picking out which diet is healthiest is like answering a multiple choice test that has a billion choices. It’s easy to go wrong.
This is where an evolutionary perspective comes in. We know that healthy people and animals are more likely to survive the vicissitudes of life and have children and grandchildren. this means that evolution selects for healthful behaviors—including healthful eating.
In the last 10,000 years, mutations have become much more common due to population growth, but most beneficial mutations have not had time to become widespread. The historical era has been a period of genetic diversification and emerging but incomplete adaptation to modern life. eat means if we want an environment, diet, and lifestyle that will be healthful for all of us, we have to look back to the Paleolithic.
In the Paleolithic, a mutation that raised the probability of having an extra child by only 0.1 percent would have reached fixation in 460,000 years. So a mutation with selective advantage of 0.1 percent would have occurred within the first 160,000 years of the Paleolithic, then become universal 460,000 years later—long before the Paleolithic was over.
In the modern era, a similar mutation would occur every year but would require 200,000 years to reach fixation. The modern era is less than 10,000 years old, however, so few recently mutated genes have had time to become universal. As a result, our genetic adaptation to the new environment of modern life—agricultural foods, city living, the presence of governments and complex institutions—is incomplete. And human genetic diversity is greater than ever before.
Because mutations that would remove our adaptation to Paleolithic diets have had little time to spread through the population, it is likely that nearly everyone is extremely well adapted to Paleolithic diets. The same cannot be said for modern diets.