Atul Gawande writes about medicine. He is himself a surgeon. He graduated from Harvard Medical School. He also holds degrees from Stanford and Oxford. He was a Rhodes scholar. Basically, he's smart as hell. (And he's fairly young, too: he's 38.) One of the great things about his writing, though, is that his big brain never leads him to leave the reader behind. In a way, he's too smart for that. His writing is as thrilling as any bestseller. For instance, when he describes a mistake that he himself made in the ER concerning a woman's blocked airway, a mistake that nearly killed the woman, he writes about it -- moment to moment -- in a way that is so immediate, so harrowing, you almost can't breathe yourself. But each vivid, fascinating account is never an end in itself. He uses these stories to illuminate difficult ethical questions inherent to his profession, questions that are relevant to all of us. The result is eloquent, profound, and wise. His book Complications is a collection of pieces, most of which first appeared in The New Yorker. Here's more information about Gawande and an interview with him. And here's a review of Complications by my pal Claire Zulkey.
The following is an excerpt from a Gawande essay, about gastric-bypass surgery, called "The Man Who Couldn't Stop Eating." (The essay is also available as a PDF.)
Apparently, how heavy one becomes is determined, in part, by how the hypothalamus and the brain stem adjudicate the conflicting signals from the mouth and the gut. Some people feel full quite early in a meal; others, like Vincent Caselli [the man to whom the title of the article refers], experience the appetizer effect for much longer. In the past several years, much has been discovered about the mechanisms of this control. We now know, for instance, that hormones, like leptin and neuropeptide Y, rise and fall with fat levels and adjust the appetite accordingly. But our knowledge of these mechanisms is still crude at best.
Consider a 1998 report concerning two men, "BR" and "RH," who suffered from profound amnesia. Like the protagonist in the movie "Memento," they could carry on a coherent conversation with you, but, once they had been distracted, they recalled nothing from as recently as a minute before, not even that they were talking to you. (BR had had a bout of viral encephalitis; RH had had a severe seizure disorder for twenty years.) Paul Rozin, a professor of psychology at the University of Pennsylvania, thought of using them in an experiment that would explore the relationship between memory and eating. On three consecutive days, he and his team brought each subject his typical lunch (BR got meat loaf, barley soup, tomatoes, potatoes, beans, bread, butter, peaches, and tea; RH got veal parmigiana with pasta, string beans, juice, and apple crumb cake). Each day, BR ate all his lunch, and RH could not quite finish. Their plates were then taken away. Ten to thirty minutes later, the researchers would reappear with the same meal. "Here's lunch," they would announce. The men ate just as much as before. Another ten to thirty minutes later, the researchers again appeared with the same meal. "Here's lunch," they would say, and again the men would eat. On a couple of occasions, the researchers even offered RH a fourth lunch. Only then did he decline, saying that his "stomach was a little tight." Stomach stretch receptors weren't completely ineffectual. Yet, in the absence of a memory of having eaten, social context alone -- someone walking in with lunch -- was enough to re-create appetite.
You can imagine forces in the brain vying to make you feel hungry or full. You have mouth receptors, smell receptors, visions of tiramisu pushing one way and gut receptors another. You have leptins and neuropeptides saying you have either too much fat stored or too little. And you have your own social and personal sense of whether eating more is a good idea. If one mechanism is thrown out of whack, there's trouble.
Here you can listen to Al Roker talk about his gastric-bypass surgery and its effect on his life.