When I explain to my patients why paleo-style eating may be the healthiest diet, I use a thought experiment. It goes like this. You find an injured or weak bird in your yard and you hope to nurse it back to health. First you need to identify the bird’s species since that will tell you what to offer as food. Most birds specialize in what they’re able to eat in order to survive and thrive. Some eat only seeds, leaves, or other plant matter. Others eat only specific insects, grubs, or worms. You get the idea. Get the food choice wrong, and you’ve got a dead bird on your hands.
Emily Deans gives a similar rationale for the paleo diet at her Psychology Today blog. She writes:
At the Cleveland Metroparks Zoo in 2005, a gorilla died of heart disease at the age of 21. Heart disease is the leading killer of captive gorillas, who also seem to be vulnerable to developing ulcerative colitis, and autoimmune disease of the gut. That led researchers to consider changing the gorilla diets, which at typical zoos had been filled with processed animal chows, meat, yogurt, milk, eggs, bread, and cereal grains along with large amounts of various fruits and vegetables. Free ranging wild gorillas, on the other hand, eat mostly immature leaves, stems, some bark, saplings, wild fruits, insects, and some small animals. The diet of the gorillas in the wild has an incredibly high fiber content, which is used as food by the may trillions of bacteria in the gorilla’s extremely long gut. The fiber is transformed into a short chain fatty acid called butyrate that is important for colonic health and may be the reason (along with the cereal grains and other unusual foods) the captive gorillas developed ulcerative colitis.