It's widely accepted these days that cooking helped make us human. It's easier to use energy from cooked food than raw, so pre-modern humans who dabbled in roasting had the energy surplus they needed to develop better brains, not to mention the time they needed to sit around and think deep thoughts with them.
According to a new study published in the Quarterly Review of Biology, cooked meat and veggies shouldn't get all the credit. Without carbohydrates, it argues, the switch to cooked food wouldn't have packed nearly as big of a punch.
For starters, sorry, vegans (and double sorry to raw vegans), but scientists generally believe that meat and cooking were totally integral to human evolution. To survive on a plant-based diet, especially a raw one, without the aid of modern conveniences like grocery stores and refrigeration, a human would have to spend pretty much all his or her time finding food.
And eating raw just isn't healthy. It isn't! It really isn't. You get fewer nutrients, women tend to stop menstruating and you'll drop a ton of weight because your body is literally going, "lol erm thanks a lot for all the food, not."
So it's not news that cooking is very, very important, in an evolutionary sense. But based on the analysis offered in this new study, those set on eating a "paleo" diet might want to make sure they're not cutting out too many carbs.
The researchers, led by Karen Hardy of the University of York and the Autonomous University of Barcelona, basically argue that the human brain relies heavily on glucose and that a lack of carbs makes it hard to keep your brain satisfied. That's true: When your body's glucose stores are low, either because you're not eating or because you've cut out carbs, your brain starts to look for energy from other sources. The results are less than ideal:
The researchers also point out that humans have around three times as many copies of the gene used to make the enzyme that turns carbs into simple sugars — salivary amylase — as other primates do. Based on genetic analysis, they say, this adaptation cropped up around 1 million years ago.
The spread of cooking — and the beginning of its visible benefits to pre-human physiology — is thought to have started around 2 million years ago, or perhaps a bit later. It would make sense, the researchers argue, if the genetic adaptation that made us efficient carb eaters cropped up after a few generations of cooking: Raw tubers are really hard for mammals to digest into usable glucose, but once we had access to cooked crops, those plants may have become quite important in our evolution — important enough that only humans with extra copies of the salivary amylase gene survived.
Infants whose mothers had more access to glucose from cooked carbs would have had higher survival rates, and carbs may have played a part in the boost in brain size seen about 800,000 years ago.
The hypothesis doesn't sound too wild, though researchers will certainly have to do more work putting together the archaeological and genetic evidence. But it's worth considering as you decide what "unnatural" foods to cut from your diet —-- if that's what you're into.
All that being said, it's important to remember that a roasted potato is very different from, say, a giant bowl of pasta. One may have led us to bigger brains, but the other is probably leading us to bigger bellies.