Historical changes in the ways we cook and eat have dramatically altered public health.
Bee Wilson is the author of Consider the Fork, which documents the evolution of cooking and eating technology. In the book, Wilson describes many unintended consequences of new methods of or materials for cooking and eating. Here she talks about some of the health ramifications of such changes.
I was struck while reading your book by how changes in the instruments we use to cook and eat can have large-scale health implications. It's especially fascinating that overbites didn't become standard until we all started eating with a knife and fork. Can you describe how that happened?
Yes, I found to be this one of the most fascinating and surprising changes to be brought about by kitchen utensils.
Until around 250 years ago in the West, archaeological evidence suggests that most human beings had an edge-to-edge bite, similar to apes. In other words, our teeth were aligned liked a guillotine, with the top layer clashing against the bottom layer. Then, quite suddenly, this alignment of the jaw changed: We developed an overbite, which is still normal today. The top layer of teeth fits over the bottom layer like a lid on a box.
This change is far too recent for any evolutionary explanation. Rather, it seems to be a question of usage. An American anthropologist, C. Loring Brace, put forward the thesis that the overbite results from the way we use cutlery, from childhood onwards.
"Women were particularly at risk from open hearths, on account of the combination of billowing skirts, trailing sleeves, and open flames."
What changed 250 years ago was the adoption of the knife and fork, which meant that we were cutting chewy food into small morsels before eating it. Previously, when eating something chewy such as meat, crusty bread or hard cheese, it would have been clamped between the jaws, then sliced with a knife or ripped with a hand -- a style of eating Professor Brace has called "stuff-and-cut."
The clincher is that the change is seen 900 years earlier in China, the reason being chopsticks.
As with any such thesis, we will probably never have definitive proof that the overbite results from the adoption of the fork, but it does seem the best fit with the evidence.
The first time I read Brace's work, I was truly astonished. So often, we assume that the tools we use for eating are more or less irrelevant -- at most, a question of manners. I found it remarkable that they could have this graphic impact on the human body.
At the same time, you write in the "Pots and Pans" chapter how until the 18th century most families had one big pot, a cauldron, that had a sort of palimpsest porridge in it -- they just kept adding new things to cook along with whatever was left over from the day before. So a lot of what people ate was soft. Were there dental changes once other ways of cooking became readily available?
The big dental change that was seen with pots happened with the initial adoption of pottery for cooking around 10, 000 years ago. Until the cooking pot was invented, no one who had lost all their teeth would survive into adulthood. There are no traces of edentulous -- toothless -- skeletons in any population without pottery. Pots made it possible for the first time to cook nourishing stew-like meals that required no chewing but could, rather, be drunk. So having teeth was no longer necessary for survival. This is another clear example of how utensils have acted as a kind of robotic extension of the human body.
On the question of why eating these soft foods didn't lead to dramatic dental changes -- such as is seen with the fork and the overbite -- I think the answer must be that they tended to be eaten alongside other, tougher foods.
But switching from a diet of mostly chewy foods to one of very soft foods can definitely have an impact on human teeth. Studies of Australian aboriginals have found that within a single generation of leaving their homes in the Outback and moving to cities (where the diet becomes one heavy in refined white flour and sugar), teeth have far less attrition (wear and tear from chewing) but many more cavities.
The big cauldron was heated over an indoor fire that, you write, was the center of the typical home. What happened after the hearth was replaced by a more removed kitchen?
One change is fewer accidental deaths from young children toddling into fires by mistake or women's billowing skirts catching ablaze as they cooked. Women were particularly at risk from open hearths, on account of the terrible combination of billowing skirts, trailing sleeves, open flames, and bubbling cauldrons. With the emergence of enclosed brick chimneys and cast iron fire grates in the 17th century, many more women became professional cooks: At last they could cook with only a minimal risk of setting fire to themselves.