I got this from the TIME article, "The Science of Appetites"
"In a study of 73 obese adults published last month in the Journal of the American Medical Association (J.A.M.A.), Dr. David Ludwig, director of the obesity program at the Children's Hospital Boston, and his colleagues looked at high- and low-insulin secretors. People who rapidly secrete a lot of insulin after eating a little bit of sugar tend to carry their excess weight around their waist—the so-called apple shape. People who secrete less insulin carry their excess fat around their hips—the pear shape. Those differences are more than aesthetic. The study found that high-insulin, apple-shaped people will not lose as much weight on a diet that restricts fat calories as they will on a low-glycemic-load diet—one that restricts simple carbohydrates from sugary and starchy foods like cookies and potatoes. Low-secreting, pear-shaped people will do equally well on either type of diet. But the results went deeper than simply how much weight was lost.
Over the course of six months, high-secreting, apple people lost an average of 6 kg on a low-glycemic diet and just 2.3 kg on a low-fat diet. Low-secreting, pear people lost about 4.5 kg on both diets. At the end of 18 months, however, the pear-shaped people had gained back half of the weight they had lost on either diet. Apple-shaped people gained back almost 1.4 of the 2.3 kg they lost on the low-fat diet but kept off all the weight they lost on the low-glycemic diet. While the study is revealing, almost nothing about it is simple. It's not clear just what the mechanism is that links body shape and insulin levels—a crucial detail if scientists are going to understand the full implications of their findings. More important, nothing suggests that apple-shaped people should simply dash out to sign up for an Atkins-type low-carbohydrate diet.
True, a large report published in J.A.M.A. earlier this year showed that regardless of body shape, Atkins produces the greatest short-term weight loss. ("If you want to look good in your wedding gown, I would go for Atkins," says Dr. Anastassios Pittas, assistant professor of medicine at Tufts University School of Medicine.) But adherents tend to fall off the low-carb wagon and quickly gain back unwanted kilograms. What's more, the Atkins diet allows only a small fraction of calories to come from carbs, compared with 40% on the new study's low-glycemic regimen. The more balanced diet allows—indeed, encourages—people to eat whole-grain cereals and other complex carbs that take longer to digest and thus don't cause the rapid fat production that accompanies spikes in blood sugar. Atkins' more restrictive regimen may reduce fat even faster, but people lose weight on both diets. "Atkins just does it with a bludgeon instead of a chisel," says Ludwig. "