There's a story going viral today entitled Raw Food Not Enough to Feed Big Brains. The author discusses a new study that found early humans would have had to have eaten more than 9 hours a day to get enough energy from unprocessed foods to grow bigger brains than primates. Suzana Herculano-Houzel, a neuroscientist and co-author of the new study says, “If you eat only raw food, there are not enough hours in the day to get enough calories to build such a large brain. We can afford more neurons, thanks to cooking.”
Our brains consume an amazing amount of our energy daily, taking 20 percent of our energy, compared to 9 percent for other primates. An earlier researcher, Richard Wrangham, proposed that humans began to evolve from primates when they discovered how to roast and cook food. Cooked food, Wrangham argued, predigests our food, making it easier to absorb and more efficient for our guts. He went on to research his theory with rodents and pythons, both of which grew larger more quickly when fed cooked food. Basically, this theory argues that the evolution of humans would have never happened without the help of cooked food.
Not surprisingly, this article and research has raised some ire in the raw food community (those who choose to only eat raw foods). Though the article states, “An ape’s diet in the wild differs from a modern 'raw food diet,' in which humans get sufficient calories from processing raw food in blenders and adding protein and other nutrients,” some felt the implications were still inherent to the research that raw food diets are insufficient for humans.
Here are some of the comments from the article. (Some comments I found just as interesting as the article itself!)
Ayursome: Ayurveda system of medicine said this 5000 years back. Raw food diet screws up the brain and nervous system badly. It effectively makes a person, an "air-head".
ness013:You can get that answer in this article, you don't even have to go back to the original study. Raw food diets still process their food in blenders and such. They even do chemical cooking that requires no external heat and they add supplements to their diet. They also have access to a variety of food that no primates would have had access to.
Chris Kendall: The failure of this article is to include what types of Calories/foods are being considered. Indeed if those on a raw diet were eating leaves for the majority of their calories they would have a huge digestive energy expenditure and take all day to eat them, that is if they chewed them well enough. The Majority of people I know on a raw food diet get the bulk of their calories from easily digestible fruits. These foods offer up more of the Nutrients we need per calorie of any food and require less digestive chemistry as well as digestive time than any cooked food save possibly Vegetable broth. This "theory" has been questioned and is no where near air tight
Evodevo: Fruit-eating chimps can't get enough calories either - they supplement their protein/fat poor diets with an occasional monkey or other small mammal. Early hominids probably started getting more calories when they began scavenging the kills of bigger predators and eating the fat calorie-dense marrow they got by smashing bones with rocks. Cooking was just another step along the evolutionary trail.
Jorge Paez: I recommend reading more about Richard Wrangham's work. Cooking is a technological improvement that eases digestion. Our jaws, teeth and guts are NOT designed to eat raw food, and as he points out "A mosquito doesn't suck blood because he luckily have a 'sharp mouth' but the other way around" Same thing with humans.
You may go deeper on his findings, in his book, Catching Fire: How Cooking Made us Human. He talks about a study which involved people with 70-100% of their diet being raw. More than a half of them –man and woman– reported important changes on their reproductive systems, being declared as 'unfit' for reproduction. The energy supply for them is just not enough, so some 'body functions' need to be sacrificed.
While the research was intended to talk about the evolutionary process, since many health food diets are based on theories of evolution/early human history, a study like this can’t help but make waves. Evolution has been used to promote everything from raw food diets (where most of your calories come from uncooked foods) to a so-called “primal” diet in which no grains and/or starches are eaten, but plenty of meats and certain vegetables and fruits. (And there are "Christian" versions of both of these diets too that don't need the support of evolutionary theories to support them.)
While I found the article and comments interesting, in the end, I feel cautious basing my diet completely on any type of theory based on something that happened “millions of years ago” in human history. Theories come and go, but I am here today and I need to eat. The food I eat is going to based more on how it makes me feel. “Junk food” makes me feel like junk, a diet rich in produce, healthy meats, and traditional fats and “soaked” grains helps me feel good. While I tweak it often, the ingredients stay mostly the same.
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