Fat Factors

Intereseting article in the NY TImes on Sunday. http://www.nytimes.com/2006/08/13/magazine/13obesity.html?ex=1313121600&en=f843a5b06faa63f8&ei=5088&partner=rssnyt&emc=rss

One thing that popped out at me, and I know it from all too personal experience, is that once you lose weight you can't go back to eating like a regular person.

This is typical of people who have lost weight — not only a lot of weight, as Janet has, but even a little weight. According to Rudolph Leibel, an obesity researcher at Columbia University who was involved in the discovery of the first human gene implicated in obesity, if you take two nonobese people of the same weight, they will require different amounts of food depending on whether or not they were once obese. It goes in precisely the maddening direction you might expect: formerly fat people need to eat less than never-fat people to maintain exactly the same weight. In other words, a 150-pound woman who has always weighed 150 might be able to get away with eating, say, 2,500 calories a day, but a 150-pound woman who once weighed more — 20 pounds more, 200 pounds more, the exact amount doesn’t matter — would have to consume about 15 percent fewer calories to keep from regaining the weight. The change occurs as soon as the person starts reducing, Leibel said, and it “is not proportional to amount of weight lost, and persists over time.”