Look, I like the Paleo Diet as much as you do–maybe even more than you do. After all, I didn’t name this blog Evolutionist X because I haven’t been reading about paleolithic peoples.
The basic idea of the Paleo Diet–in case you’ve been living under a rock–is that you will be healthier if you eat only veggies, fruit, and meat (no grains or milk products,)–the diet your Paleolithic ancestors evolved to eat.
The problem with the Paleo Diet is that evolution did not stop 10,000 years ago. Evolution is constant. It doesn’t stop. You are not a caveman in a suit. You are a modern person. Unless your grandparents were hunter-gatherers, chances are good that your ancestors have been under significant evolutionary pressure to adapt to agriculture for thousands of years.
For example, Lactase Persistence evolved in dairying populations entirely within the last 10,000 years. Today, 80% of Europeans and European-descended people have the gene for lactase persistence. Outside of traditionally dairying areas, this trait is rare. It has spread entirely in response to the development of dairying–which means that if your ancestors have been raising animals for their milk for the past few thousand years, there is a very good chance that you are adapted to drinking milk well after infancy.
Of course, you’re probably not going to hurt yourself drinking water instead.
Likewise for wheat; if your ancestors have been eating wheat for thousands of years, you can probably digest it okay. If your ancestors haven’t been eating wheat for thousands of years, then you might want to avoid it–a Vietnamese friend of mine gets stomach aches from eating wheat (especially whole wheat, which contains more of the irritating chemicals from the external part of of the grain, designed to inspire your stomach to pass out the seed within without digesting it). Their ancestors ate rice, not wheat, so this is hardly surprising. (They also are lactose intolerant, since their ancestors did not keep dairy cows.) However, they have no difficulties digesting rice–a food they are adapted to eat.
If you aren’t adapted to wheat, wheat will give you a stomach ache. If wheat gives you a stomach ache, avoid it! But if your ancestors ate wheat and it doesn’t give you a stomach ache, you’ll probably be safe eating it.
It is reasonable to ask whether there are long-term bad effects from eating wheat or drinking milk–some disease that doesn’t kick in until you’re in your 70s, for example, would be difficult to develop adaptations to combat because it kills you after you’ve already had all of your kids. On this count, I would love to see more research.
Also, there may be some people who, like the 20% or so of Europeans who lack lactase persistence, are particularly sensitive to various foods. People with the ApoE4 gene (the “Alzheimer’s Gene”) may benefit from specific dietary modifications.
However, there’s no particular reason to believe that you are all that well-adapted to eating a diet your ancestors haven’t eaten in thousands of years.