There has been explosive interest in the last few years in eating like our ancient, pre-agricultural ancestors: following a hunter-gatherer pattern that would have been the norm in the Paleolithic Era (the “stone age”). The idea behind this is that agriculture has only been around for about 10,000 years, which is barely a blip on the evolutionary time scale. Therefore, our genes are still adapted mostly to eating grass-fed meat, eggs, fish, fruits, nuts, and vegetables. Foods that were introduced with agriculture – especially grains and beans – are harder to digest, and (so the logic goes) may actually contribute to health problems.
With my studies of biology in college, I am all on board the argument of genetic adaptation. However, I think we need to look at the Paleo Diet critically to determine if it’s really the healthiest way to eat.
- Peer-reviewed, published scientific studies about the Paleo Diet (of which there are fewer than ten) have mainly focused on short-term changes in specific parameters, like body weight, blood sugar, and blood cholesterol levels. While there is definite benefit in these areas, the research has not gone as far as to prove lower risk of chronic disease or mortality (i.e., risk of dying early).
- The complete elimination of grains contradicts many studies that show decreased risk of chronic metabolic diseases. Last month, Chinese researchers published data on over 367,000 participants, showing decreased all-cause mortality (that is, dying for any reason) with high consumption of fiber-rich whole grains.
- The argument that our genes have not had time to adapt to an agricultural diet ignores some biological nuances. Sometimes genetic mutations can confer an advantage, and spread quickly — the best example of this is the ability to produce the lactase enzyme into adulthood, which appeared just a few thousand years ago. This allowed some populations to survive better than their neighbors, by taking advantage of dairy as a source of nutrition. Another wrinkle is the relatively new field of epigenetics, which has found that though our genetic code may not change much, certain genes may be “turned on” or “turned off” (biochemically) in response to environmental pressures. This can happen within a single generation, and the changes can even be passed on to offspring.
The Paleo Diet can serve some important functions. As a structured system, it is a good way to break our addiction to sugar and refined carbohydrates, which is one of the leading causes of chronic disease. By eliminating many common foods, the Paleo Diet can also serve as a tool to help identify foods that may be causing inflammatory reactions in the body. For the long term, however, I still recommend the Mediterranean Diet (including – gasp! – whole grains), which has a mountain of evidence on improved health outcomes and longer lifespan.