STILL PROCESSING

Why is the American diet so deadly?

- DHRUV KHULLAR

Until recently, Guillaume Raineri, a forty-two-year-old man with a bald head and a bushy goatee, worked as an HVAC technician in Gonesse, a small town about ten miles north of Paris. The area lends its name to pain de Gonesse, a bread historically made from wheat that was grown locally, milled with a special process, and fermented slowly to develop flavor. The French élite once savored its crisp yet chewy crust and its tender, subtly sweet crumb. Raineri would occasionally grab a loaf from a boulangerie after work. He doesn't consider himself a foodie-"but, you know, I'm French," he told me.

After Raineri's wife got a job at the National Institutes of Health, in Bethesda, Maryland, they moved to the U.S. The transition was something of a shock. "The food here is different," he said in a heavy French accent. "Bigger portions. Too much salt. Too much sugar." He decided to enroll in a paid study at his wife's new workplace. It was exploring why the American diet, compared with almost any other, causes people to gain weight and develop chronic diseases at such staggering rates. "I wanted to know what is good for my body," he told me.

In November, for four weeks, Raineri moved into a room that featured a narrow hospital bed, an austere blue recliner, and an exercise bike, which he was supposed to use for an hour a day. "It's not as bad as it looks," he said. His wife took to visiting him at the end of her shifts. Once a week, he spent a full twenty-four hours inside a metabolic chamber, a small room that measured how his body used food, air, and water. He was not allowed to go outside unsupervised, owing to the risk that he might sneak a few morsels of unsanctioned food.