It is thought that much human evolution occurred during the Pleistocene – 2.8 million to 12 thousand years ago. What are the consequences of genes optimized for a Pleistocene environment now expressed in the modern environment? We have new technology, petro-chemicals, artificial light, recreational drugs. In particular, we consume radically different food than our predecessors. Are we healthier if we eat like we did in the Pleistocene?
This thinking has led to a Paleo lifestyle movement that advocates for a Paleo diet. This concept has become popular in part because it prioritizes eating meat and some high fat foods. But is this really the healthiest option, and the best evolutionary insight as to what we should be eating? What exactly is the Paleo diet, and how much should we worry about eating only foods that we were evolved to eat?
The Paleo diet raises additional questions. There is tremendous diversity in modern human diets, even among traditional human populations. Which stone age populations should we emulate? Can we really know how our Pleistocene ancestors ate with any certainty? How far back should we go – 1,000 years, 10,000 years, 100,000 years -to pinpoint the healthiest evolved diet for humans? Can modern hunter-gatherers, like the Hadza of Tanzania be a stand-in for our ancestral hominins in terms of diet?
[Students – check back this weekend for journal club assignments. You will be expected to present your journal club critiques on October 4th to give you sufficient time. We will be discussing Paleo diets on September 27th]
Assignment due September 27th: Of the different sources of animal protein, fish seems to be very healthy, maybe even the healthiest, in the human diet. Elaine Morgan, an Oxford trained anthropologist, argues that early humans had an aquatic phase – the so called “aquatic ape” hypothesis, first proposed by marine biologist Alister Hardy. Morgan, Hardy, and others propose that early aquatic humans spent a lot of time in the water, explaining our lack of hair and tails, the ability to hold our breath, our upright posture good for wading, and our air filled sinuses. Aquatic apes would have eaten a lot of seafood, rich in omega-3 fatty acids, useful in brain development, maybe even permitting humans to evolve large brains. Argue for or against the idea that an aquatic phase for humanity explains why fish, and marine omega-3 fatty acids, are healthy for us humans.