Journal: If Dieting Doesn't Work, What Does?!

Will you lose weight and keep it off if you diet? No, probably not, researchers report.

"You can initially lose 5 to 10 percent of your weight on any number of diets, but then the weight comes back," said Traci Mann, UCLA associate professor of psychology and lead author of the study. "We found that the majority of people regained all the weight, plus more. Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority. Diets do not lead to sustained weight loss or health benefits for the majority of people."

"What happens to people on diets in the long run?" Mann asked. "Would they have been better off to not go on a diet at all? We decided to dig up and analyze every study that followed people on diets for two to five years. We concluded most of them would have been better off not going on the diet at all. Their weight would be pretty much the same, and their bodies would not suffer the wear and tear from losing weight and gaining it all back."

People on diets typically lose 5 to 10 percent of their starting weight in the first six months, the researchers found. However, at least one-third to two-thirds of people on diets regain more weight than they lost within four or five years, and the true number may well be significantly higher, they said.

If dieting doesn't work, what does?
"Eating in moderation is a good idea for everybody, and so is regular exercise," Mann said. "That is not what we looked at in this study. Exercise may well be the key factor leading to sustained weight loss. Studies consistently find that people who reported the most exercise also had the most weight loss."