• Glenn Wilson
    82
    Dr. Greger: Our epidemics of dietary disease have prompted a great deal of research into what humans are meant to eat for optimal health. In 1985, an influential article was published, proposing that our chronic diseases stem from a disconnect between what our bodies evolved eating during the Stone Age, or the Paleolithic period, during the last two million years and what now makes up our diet, and advocating for a return towards a hunter-gatherer type of diet of lean meat, fruits, vegetables, and nuts, also known as the so-called Paleo Diet.

    It might be reasonable to assume our nutritional requirements were established in the past, but why the Paleolithic period? Why only the last two million years of human evolution?

    We have been evolving for about 20 million years since we split off from our last common great ape ancestor, during which time our nutrient requirements and digestive physiology were relatively set and likely little affected by our hunter-gatherer days at the tail end. So what were we eating for the first 90 percent of our time on Earth? What the rest of the Great Apes were eating: more than 95 percent plants. Indeed, for the vast majority of our evolution, it appears we, like our Great Ape cousins, ate primarily leaves, stems, and shoots (in other words, vegetables), and fruit, seeds, and nuts.

    More at the NutritionFacts topic page: Paleolithic Diets.


    What can our nutrient requirements, metabolism, and physiology tell us about what we should be eating?

    Dr. Greger: This could explain why fruits and vegetables are not only just so good for us, but vital to our survival. We’re actually one of the few species so adapted to a plant-based diet, that we could actually die from not eating fruits and vegetables—from the vitamin C-deficiency disease, scurvy. Most other animals just make their own vitamin C. But why would our body waste all that effort when we evolved hanging out in the trees, just eating fruits and veggies all day long?

    It’s presumably not a coincidence that the few other mammals unable to synthesize their own vitamin C (like guinea pigs, some bunny rabbits, and fruit bats) are all, like us great apes, strongly herbivorous. Even during the Stone Age, we may have been getting up to ten times more vitamin C than we get today. And ten times more dietary fiber, based on essentially rehydrated human fossilized feces. The question is: are these incredibly high nutrient intakes simply an unavoidable by-product of eating whole, plant foods all the time, or might they actually be serving some important function, like antioxidant defense?

    Plants create antioxidants to defend their own structures against free radicals. The human body must defend itself against the same types of pro-oxidants. And so, we have also evolved an array of amazing antioxidant enzymes, which is effective, but not infallible. Free radicals can breach our defenses, and cause damage that accumulates with age, leading to a variety of disease-causing and, ultimately fatal, changes. That’s where plants may come in.

    Continue at NutritionFacts: What’s the “Natural” Human Diet?

    Maybe you prefer to read the transcript instead of watching this video? To see the full transcript or links to cited sources go to the link above, then scroll below the video and click on View Transcript or Sources Cited.

    More in the category Health and Medical.

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