If you listen to health food programming these days, it’s very down on processed food. But it turns out that processed food–in this case, cooked food–gave our ancestors a huge advantage when it came to survival. But knowing when this innovation occurred is difficult. But new research suggests that our teeth tell us when this happened: about 2 million years ago.
Softer Food and Smaller Teeth
The advantage of cooking is that it can begin breaking down our food before we even put it in our mouth. The process of chewing does two things: break food up into smaller pieces and break it down chemically by mixing it with saliva. Our teeth have the hard job of performing this work. They are designed to crush and break hard foods that have a lot of tough material in it. But when we cut up food with knives and cook it with fire, we are already performing some of these functions, and that means we have less need for the large molars that other primate relatives had.
And researchers report that the change from eating raw food to cooked food can be read in the fossil record as occurring at least 1.9 million years ago, with or before the appearance of Homo erectus, the first of our ancestors who had disproportionately small molars.
And over time our jaws would continue to shrink to the point that they were barely big enough for the teeth we have, leading to the common need for wisdom tooth extraction and contributing to our risk of TMJ.
The Benefits of Less Chewing
Have you ever wondered what our primate relatives do all day? The truth of the matter is they spend most of it eating. And we would, too, if it weren’t for cooking. According to researchers, based on our size, we would spend about 48% of the day eating. And although spending half the day at an all-you-can-eat buffet might sound good, you have to think that you’d actually be spending most of this time just chewing, chewing, chewing on raw grass and twigs. Not quite like going back for a second plate at Golden Corral.
And not spending all our time chewing has another benefit. Spending less time with our mouths full of food meant we could devote more time to developing the skill of conversation, which is a big part of what makes modern meals so good, too.
The down side is that we would face a new problem: bacterial infection leading to tooth decay and gum disease. Our new concentrated food made our mouths a better environment for parasitic bacteria, which then attacked our teeth and gums. But that’s what dentists are for, taking care of these modern-life problems.