Mary Roach on the fascinating - and gross! - science of eating

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First aired on The Current (01/04/13)


Science writer Mary Roach has a strong constitution. Her books delve into the bizarre (and, occasionally, gross) scientific specifics behind things like death (Stiff), ghosts (Spook), sex (Bonk) and space (Packing for Mars, for which she appparently abandoned her single word title policy). Her latest book, Gulp: Adventures on the Alimentary Canal, is about the science behind the food we eat, how we eat it and what happens to it after we've swallowed the last bite. Roach spoke with guest host Rick MacInnes Rae on The Current in a recent interview.

Gulp is filled with fantastic obscure words pertaining to mastication and digestion. Learning words like "borborygmi" (which refers to the sound of intestinal rumbling) and "bolus" (a mass of food that has been chewed to the point of swallowing -- we advise you NOT to do a Google image search for "bolus") was one of Roach's favourite things about working on Gulp. "I love words, but I also love finding out that there is a word for something that you've experienced but didn't know there was a word for," said Roach. "Like 'toothpack' -- that is a word for when you eat biscuits or cookies and you get that annoying layer of chewed substance on your molars that you kind of have to pick out."

Gulp focuses on the sometimes disgusting but always fascinating details of what happens along the alimentary canal, which runs from where food goes in (the mouth, of course) to where it inevitably comes out (the anus -- no need to be squeamish about it). "That's the whole chute, all the way through, the whole nine yards," said Roach.

One of the strange idiosyncracies of the stomach that Roach explores in her book is why some people -- say, the type of people who win hot dog eating contests -- are able to eat more than average. "Some people have -- this is the technical term -- compliant stomachs," she said. "They don't have an exceptionally large stomach, but it's very stretchy, it's willing to accommodate an incredible amount. I talked to [one] competitive eater and he said that from the time he was a kid, he was always...a kid who could eat [a lot], while not necessarily getting fat and gaining weight."

For those of us with less compliant stomachs, however, our bodies have certain defence mechanisms to prevent us from eating ourselves to illness, like the feeling of bloat caused by the pressure of gas inside the stomach, and (maybe put down whatever you're eating right now) regurgitation. In fact, it is extremely rare for someone to eat his or herself to death.

Roach, who approaches all her subjects with curiosity, didn't know what she'd find on her alimentary journey. "The human food processor is a marvellous and very strange machine," she said. "It's almost its own world. Starting with the mouth and going all the way through, it's kind of like a special zone...there's bacteria in there, putrefaction, everything you don't want happening in a body is allowed to happen [in the alimentary canal]. It's this kind of crazy world inside your own body."

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