DIET: Watching calories a lifelong commitment, study suggests

ST. LOUIS (AP) -- A University of South Florida researcher says people trying to stay thin should take a lesson from the chunky monkeys in her study.

Barbara Hansen's two-decade South Florida study says genetic differences allow some primates to remain thin and others to grow fat when fed an identical diet over the years.

Overweight monkeys that were forced to cut calories by as much as 25 percent lost weight.

But once those caloric restrictions were lifted, they regained the weight -- regardless of whether they'd been on a diet for two months or two years.

Hansen says monkeys fed 30 percent less over the long term extended their lifetimes to 30 years.

The average life-span is 23 years.

Hansen presented her research in St. Louis today at the annual meeting of the American Association for the Advancement of Science.