Many advocate eating raw food. Is this a good thing or not?
Dr Richard Wrangham thinks not. His work suggests that humans have been cooking for a very long time. For well over a million years. There is no fossil record of fires but there is a physiological record. Homo Erectus lost that big veggie processing gut and those big veggie grinding teeth and jaws. And HE’s brain increased by 20%. I find this pretty convincing. (A good intro to his ideas is here)
It would take a massive change in environment to create this change to the body plan.
Here is a short video where Wrangham speaks to his findings
He also looked at a large modern study to see how well people do on a veggie diet. (source)
There are only three studies conducted on the body weight of raw foodists, according to Wrangham’s book. The most comprehensive of them was the Geissen study, which questioned and examined 513 raw foodists. This isn’t quite as legit as confining people to a zoo for 30 years, but what was shown was that the higher the percentage of raw food in the diet, irrespective of whether or not they consumed meat, the lower their BMI. One third of those who ate purely raw had body weights that categorized them as being in a state of chronic energy deficiency. The Geissen study also found that 82% of long term raw foodists included some cooked food in their diets. The study also showed that the more raw food women ate, the less likely they were to have regular periods, many of whom had completely ceased to menstruate. This equates to being infertile and losing bone mass. Some raw foodists (and I did hear this one at a raw food guru talk I attended once upon a time in Boulder) claim that menstruation and ejaculation are just a body’s way of eliminating toxins and once you become truly clean, ejaculating and menstruating is no longer necessary. Facepalm! Seriously, I remember the promises of menstrual cycles practically becoming “unnecessary”, provided you really stuck to it. While this does sound like an upshot, it’s kind of like promoting the loss of your legs by saying you’ll never have to run 400m repeats. Locomotion: just for the overachievers!
The last sort-of nail in the coffin for the theory that raw foods are our evolved diet, is that they would never work in the wild. Wrangham found no reports of long term survival in the wild on a raw diet. Most commonly, rapid starvation is the biggest threat to survival in the wild on raw foods, even with intimate knowledge of edible forage, just ask Robb and the I Cavemen cast. What makes a modern raw foods diet livable is that we now have unlimited access to food processing, making nutrients a little more available. Blenders, dehydrators, grinders, sprouting, and grocery stores that can provide year-round access to produce and nut butter that clearly would be hard to scrounge up in the wild. Also keep in mind that these domesticates are a wee bit more energy dense than they were in the wild. The German team also found that 30% of the raw foodists’ calories came from lipids that would have been inaccessible to any hunter gatherer.
So without these modern conveniences, how well do you think they would do? Anybody really wanna try? And judging by the fact that many of them cease to be reproductively functional, how well do you think we’d do if this was our evolutionary strategy?
It looks to me that a diet that makes nearly half the sample infertile is unlikely to be a sound one and to have any basis in our own past. And imagine eating only raw food in a northern winter without the modern food system.