I previously wrote about some mathematical laws that dictated why we cook the way that we do. But beyond the details – why we use certain spices or combine specific ingredients – why do we cook at all? There are the classic answers: It tastes better, lasts longer, and can get rid of bacteria. But in the past decade or so, there has been a growing discussion of whether we cook food because it makes digesting more efficient.
Essentially, the argument is that cooking predigests food. Therefore, when we eat cooked food we have to use less energy to digest what we eat. Anecdotally, this seems compelling, especially when one learns that chimpanzees spend more than six hours a day just chewing their food. This makes Chester Arthur’s three-hour dinners seem less extravagant.
But we can go beyond the anecdote. Pythons have been studied and found to use less energy after eating ground meat or cooked meat than when given a piece of meat whole or uncooked. Processing one’s food outside your body reduces the energy needed to break it down inside your body. These findings have been expanded into a more developed hypothesis, discussed at length in the book Catching Fire: How Cooking Made Us Human by Richard Wrangham. In Catching Fire, Wrangham argues that we eat cooked food because it gives us more free time, and allows us to preserve energy and use it for other things, like building civilization. And perhaps that’s why cooked food tastes better: We have evolved to prefer food that takes less energy to digest.
And recently, there was a study that buttressed this argument. Looking at recipes online, researchers found that the more predigested a dish was, the more highly rated it was on recipe sites. Specifically, if a recipe calls for simply tossing ingredients together (a mechanical method for combining ingredients) the average rating was lower than if the food was heated. This in turn was rated less than foods that had been processed by chemical methods, such as marination or fermentation.