Fire and Paleo Diet: Loren Cordain Responds

All true, fair, and important, but the counter is that Wrangham didn't talk about only tubers, and fire makes food of all sorts more available--including meat. Cooking kills the parasites, for one thing. The main thing wrong with this post, though, is that Cordain is skipping over the calories per acre question. There is only so much meat out there, even in Africa. Plant biomass is always going to be much greater. The modern human diet in virtually all groups studied is 10--20% meat (except in environments like the Arctic, far from anywhere people evolved). We can safely infer that early hominins did not ignore all those berries, fruits, shoots, nuts, etc. that abound in Africa as elsewhere. Early humans were highly opportunistic omnivores. Cooking helped them. More to the point, though, is that people like to be fire-followers, and all human groups that live in burnable environments burn said environments to open them up and produce more food that people can eat. It's a lot easier to burn brush, and to learn how to burn brush, than to cook. I have always assumed that people learned to use and control fire via that route. They started off following natural fires and gradually learned to control the fires. Cooking came later.

While the fatty acid argument has merit, the caloric density argument doesn't hold water. If tubers are less calorically dense than meat, can not humans just eat a bigger volume of tubers (as humans for ages have done)? It seems to me that for hunter-gatherers, getting a bunch of tubers likely usually is much easier than getting even a smaller volume of meat.

ARMED WITH ONLY A ATTENBOROUGH DOCO, MAY I INSERT THAT CHIMPS HUNT FOR MEAT?

Hi Gene and Richard, I think you hit the issue on the head. I'll try to come up with a more detailed response in the next day or two, and post it on the blog.

It's not all about calories, it's more about nutrients, key nutrients that lack in tubers and also in vegetables and fruits, they were backup food when meat was not avaialble. The calories stuff drives me nuts because it's only one small part of the issue. Of course we tend to simplify, but oversimplification means considering one variable inside a billions variables equation. We are far from being calorimeters that burn all the stuff we throw inside, we are very complex beings and different macro and micro nutrients in sinergy drive different methabolic patways. And nature through evolution selected our gut and stomach for a certain mass of food at time with a certain nutrient density, you can't eat tons of tubers and vegetables hoping to get all that we need, also because we don't absorbe much from them.since they not only lack of key molecules, but the others are mostly binded with antinutrients that are only partially broken by cooking. The cooking claim that made us human is half bogus. There are some hints: the slope of the encephalization curve was already set off before the domesticazion of fire. Second, with the advent of agriculture we had everything cooked, but cereal grains and other nutritionally poor stuff that replaced meat made us strikingly weak, short and sick and our brain shrinked. Hunter gatherers that hardly rely on tubers like Inuit were much healthier and stronger than us, and that means that they are not a key food for us but rather more a backup food. Actually it seems that Nature provides the right balance between predators and preys and starvation is not the norm, until we human beings manage to disrupt every mechanism.Some studied "modern" hunter gatherers live in a backup land confined by our civilization and the fact that they highly rely on tubers and stay relatively healthy compared to us doesn't necessarily mean that they have the "best" diet but for me it means that after all we have a certain flexibility to survive and such flexibility was most probably the key of our success, but everything is not black and white and there are many shades of gray. The problem for me is that nutritionists lack of evolutionary education and anthropologists lack of nutritional education, it takes an higher perspective to analyze data. If you lack of the key principles of nutrition you come out with claiming that it's all about calorie totally ignoring the role of DHA, AA, creatine, carnitine, carnosine, vitamin B12, eme-iron etc. etc. that make vegan diet a nutritional disaster. Fortunately Dr. Cordain seems to own both of the skills and though some things are still controversial, he has a very high perspective of the issue to collect the pieces of the puzzle.

CJ Hunt, the reporter of The Perfect Human Diet, did some interesting interviews with some anthropologists like Mannini and others and it came out that it's not discounted that humans had been limping around eating whatever they found. I think that it's very likely that some periods of starvation occured, but pointing out that backup food poorly nutritional made the major amount of our diet it's not consistent neither with the many pieces of the puzzle nor with the evidence (whenever you look at the vegan populations like Indians and vegan people around the world you see a strikingly lack of nourishment, and not only from raw vegans, also from the cooking vegans as well. And archelogical records clearly shows an astonishing drop of health condition from a meat based diet to a cereal grains based one where everything was well cooked since you can't eat grains raw. And they were the alleged healthy whole grains I guess since the modern way to refine and process them had not been invented yet. Further, when a lion is through a period of starvation, it doesn't make a non species appropriate food as a staple, because its physiology can't handle alien food, as the evidence coming from our digestive tract (short gut compared to the other primates), enzymatic wealth (very poor compared to herbivores and granivores) is closer to a pure carnivore than a bird or a cow, somewhere between a chimp and a feline, a great hint to expect that meat itself played a huge role in our evolutionary path.

With our amazing ingenuity we managed to make edible an otherwise totally digestible food for our species, but at the same time it will never be able to substitute the food we are actually shaped to eat and that made us human. You can't get DHA, creatine, carnitine, taurine, B12, eme-iron, etc.. from the alleged plant based diet, because some of such key nutrients totally lack in plants and some others are poorly bioavailable even if they are cooked. If it's true that with cooking you can extract some nutrients breaking down antinutrients, it's also true that you're going to lose some other key nutrients. At least it's advisable to cook some stuff and eating raw others. You can't take enough vitamin C if you cook everything for example and DHA is going to be degradated at relatively low temperatures, suggesting that well cooked meat should at least be alterned with bloody steaks.

There is actually good evidence that the body can synthesize the required fatty acids endogenously, and this conversion is actually fairly tightly regulated. The brains reliance on glucose as energy seems to be a sign that it was humans access to glucose that accounted for rapid brain development. If there is a lack of exogenous glucose, then the body will break down muscle tissue and fat stores to give the brain glucose via ketones and gluconeogenisis. This blogger does a very good job of providing an argument against the necessity of exogenous DHA and other fatty acids. http://tanyewwei.com/blog/dha/#endogenous-dha-synthesis