What is paleo?
A week ago in a friend's housewarming party I ended up having a conversation about diets, nutrition, and health (I wonder why this always happens... Is it just me or is this such a common topic?). The person I was talking with asked me for my opinion on paleo, or paleo diet, also known as primal or caveman diet. I thought it was such a good question that it definitely should warrant a more detailed answer - especially considering that a lot of the things I would recommend to people if they want to improve their health and performance are rooted in the paleo mindset.
Paleo diet, in short, consists of foods that humans ate and had access to during the paleolithic era. Foods such as meat, fish, shellfish, eggs, nuts, tubers, vegetables, roots, berries, fruit, mushrooms etc. - basically whatever you could get by hunting and gathering.
This is in stark contrast to neolithic era foods which include grains, legumes, dairy, beans, and potatoes. Also processed foods are on the off-list for those following paleo diet as those have been around for only about a century.
The underlying reason why we should eat paleolithic foods instead of neolithic ones is that during the course of human evolution we have adapted to a specific type of diet. Those individuals who have been able to thrive best with the foods available prior to agriculture are the ones who have survived and produced offspring.
The paleolithic era lasted from around 2.6 million years BC until the advent of agriculture around 10.000 years BC. Agriculture meant a major change in the diet of our ancestors, and considering that we spent hundreds of thousands of years on a very different kind of diet, our genes have not yet had enough time to adapt to do well with agricultural products. We tolerate them to some extent, but they do more harm than good if you want to optimize health and performance. Same logic can be used to processed foods which have been around for an even shorter time.
When talking about paleo diet, there are couple caveats that I think should always be considered:
Selection bias
The evidence we have on how our paleolithic ancestors ate is mainly based on archaeological findings (e.g. stone tools, spearheads stuck in the bones of huge game animals, fossilized remains) and research done on the modern-day hunter-gatherer populations such as the Masai and the Kitavans.
In other words, we do not have a complete, 100% accurate picture of what our ancestors ate. There may be relevant factors of which we have absolutely no idea because we have not found any evidence of them. Also, there is no consensus on things like the ratio of animal based vs. plant based foods, or cooked vs. raw foods.
Grey areas
A quick Google search will show you just how many different paleo diet and lifestyle websites there are, so it shouldn't be a surprise that even amongst the proponents of paleo diet there are different perspectives and viewpoints on what the optimal diet should and should not consist of.
Practical application
Should we all go out and start hunting and gathering our food? Should we leave everything out of our diet that was not available to our paleolithic ancestors? I think not. Partly because of the selection bias and the limited information we can gather, but also because even though our ancestors did not eat something, it does not automatically mean that it would be bad for us.
Now we can get to the point I want to make about paleo, or at least share my personal opinion on paleo diet and lifestyle: paleo is a template, a framework, and a standpoint. It is rooted in evolutionary biology and gives us a solid foundation from which to generate hypotheses for testing. We can use the paleo framework to ask questions such as "if macronutrient composition is the same, but Group A uses grains as a carbohydrate source and Group B uses tubers, how does that affect biomarkers of health and disease?"
The premise of paleo diet would indicate that tubers are more healthy for us than grains. However we cannot make that conclusion without any evidence. Similarly we should not try to perfectly emulate the ancestral diet or lifestyle "just because." For example, I'm sure my paleolithic ancestor did not drink espressos, but it doesn't mean that I shouldn't - unless we start seeing proof that coffee consumption causes significant health issues.
We need to ask questions, do research, and through that process find out which aspects of the ancestral diet we should incorporate into our lives, where we can have some leeway, and what kind of trade-offs are required to optimize health. Individual variations will also come into play here. For example, I don't experience problems if I keep my dairy intake relatively low; butter for cooking and a shot of milk with coffee. Feed me a bagel or some cake and within 24-hours I get stomach pain and bloating. Every time I choose to eat something like that I am making a conscious choice of trading momentary pleasure for some future pain.
The next question is, can you actually benefit from following a paleo diet? I would say yes. A growing body of research indicates that grains, legumes and dairy are behind many of the so called diseases of civilization, and even if you don't have any direct gastrointestinal problems or a clear-cut case of celiac disease most - if not all - people can improve their health by eliminating these foods from their diets.
And as Robb Wolf puts it; give paleo diet a 30-day trial. See how you look, feel, and perform. Then you can start reintroducing neolithic foods and see how well you tolerate them. You have nothing to lose with this approach, but you're likely to end up feeling better than you ever thought possible, and by introducing foods back one at a time you can track your reaction to them with relative ease.