Abstract from yahoo news , kinda inspiring huh?

"If dieting worked, there would be a bunch of skinny people walking around," said obesity researcher Dr. David Katz, head of Yale University's Prevention Research Center, who did not participate in the latest study.

Since the 1970s, the ranks of overweight and obese Americans have risen with two-thirds of adults in that category. Obesity raises the risk of heart disease, diabetes and some cancers. Being overweight increases blood pressure and cholesterol levels which can lead to heart disease.

Many factors can conspire against successful weight reduction, health experts say. Diets can be boring and there's always a temptation to return to old habits. Serial dieters may also become discouraged and give up when their weight plateaus. People who lose too much too soon don't learn to make the overall lifestyle changes — eating healthier foods and exercising regularly — that are necessary to keep their weight stable.

"It's just plain difficult to modify your diet and turn away from the pleasures of eating," said Michael Goran, an obesity researcher at the University of Southern California. "We're driven to eat."