Use your imagination and picture our ancestors lives thousands of years ago. Day in and day out, generation after generation for hundreds of thousands, if not millions of years every single one of our ancestors was a hunter /gatherer. Even if you only go back as far as our own species of Homo sapiens, which appeared on the scene 40,000 years ago, every single one of our ancient grandparents for 30,000 years was a hunter/gatherer. All of our ancient ancestors ate only fruits, roots, legumes, nuts, and other plants with a little lean wild game, honey, and eggs. There was no refined grains, no refined sugar, no processed food, no food additives. Yet the bones of these ancestors reflect a level of fitness similar to today’s well-trained athlete. There is also evidence that those who weren’t killed by saber tooth tigers or who didn’t die of an infection, lived robustly into old age.
Then came farming. About 8,000 to 10,000 years ago, our ancestors discovered agriculture and settled into larger communities. They became less physically active and ate more, but from less-varied diets. The Industrial Revolution hit 200 years ago and further reduced daily activity, while escalating food processing. For 100,000 generations people had been hunters and gatherers. Compare that to the 500 generations people have been farmers, the 10 generations since the Industrial Age, and the one generation since computers and you see that there have been major changes in how we live and eat in a very short period of time.
Therein lies the problem. It takes tens of thousands of years for the body to adapt to even small changes in the environment. Our biochemistry and physiology remain fine-tuned to diets and activity levels that existed before 10,000 years ago. That means diets rich in colorful fruits and vegetables, legumes, extra-lean meats (typically wild game, not domesticated meat), seafood, and other real, unproccessed foods that we now call “healthy.”