The most searched-for diet earlier this year was 鈥淧aleo diet鈥�
Our bodies didn鈥檛 evolve for lying on a sofa watching TV and eating chips and ice cream. They evolved for running around hunting game and gathering fruit and vegetables. So, the myth goes, we鈥檇 all be a lot healthier if we lived and ate more like our ancestors.
This 鈥渆volutionary discordance hypothesis鈥� was first put forward in 1985 by medic S. Boyd Eaton and anthropologist Melvin Konner, both of Emory University in Atlanta, Georgia (). In it they claimed that while our genes haven鈥檛 changed for at least 50,000 years, our diets and lifestyles have changed greatly since the advent of agriculture 10,000 years ago, and it has all happened too quickly for us to evolve to deal with it. This, they argued, is the reason why diabetes, heart disease and cancers are rife. If we could only exercise more and eat like hunter-gatherers, we鈥檇 be fitter, happier and healthier.
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In recent years, the Stone Age or 鈥減aleo鈥� diet based on these ideas has become very popular. It involves eating game, fish, fruit, vegetables and nuts, and avoiding grains, dairy, legumes, oils, refined sugars and salt. Some aspects, such as exercising more and eating less highly processed grains and sugars, agree with the latest evidence. But others, such as ditching grains, legumes and dairy, do not. And the underlying rationale is flawed.
The idea that there was some evolutionary sweet spot 50,000 years ago just isn鈥檛 true, says Marlene Zuk, an evolutionary biologist at the University of Minnesota in Saint Paul, who has written a book debunking the paleo lifestyle. Our ancestors were not perfectly adapted to their lifestyles, and we have adapted to our agricultural diet.
For instance, many people for digesting the starch found in grains. The ability to digest milk as an adult 鈥� lactose tolerance 鈥� has also evolved independently in several populations.
Another criticism is that we don鈥檛 know for sure what our ancestors ate. They definitely didn鈥檛 eat anything like the animals and plants we eat today, which have been transformed beyond recognition by selective breeding. Last but not least, it鈥檚 not clear that ancient hunter-gatherers really were that much healthier than the rest of us (). Evolution, after all, doesn鈥檛 care if we drop dead once we鈥檝e raised our children and grandchildren.
The original proponents of the discordance hypothesis still stand by their idea, but they have revised it in light of the latest evidence. Eaton and Konner now include low-fat dairy products and whole grains in their recommended foods ().
Read more: 鈥�Don鈥檛 swallow it: Six health myths you should ignore鈥�
This article appeared in print under the headline 鈥�6 we should live and eat like cavemen鈥�
