Jacinda Nicklas of the Beth Israel Deaconess Medical Center in Boston said it is possible for obese people to lose weight and national survey data indicated many do.
Nicklas said diet and exercise were the big factors that worked.
"Americans with obesity are having success with some of the tried-and-true methods of weight loss -- eating less fat, exercising more and also using other techniques, like prescription weight loss medicines and commercial weight loss programs," Nicklas said in a statement.
The study was published in the American Journal of Preventive Medicine.
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