Rockefeller University (search) obesity expert says there's thin evidence supporting the notion that the United States is suffering from a fat epidemic.

Dr. Jeffrey Friedman (search), who discovered the gene for leptin, a hormone released by fat cells, contends that national statistics do not really indicate that Americans are becoming uniformly fatter, the New York Times reported.

While the data do show that very fat Americans are getting fatter, thinner people are only slightly heavier overall than they were in the early 1990s, Friedman said.

He expressed outrage about widespread acceptance of what he regards as a harmful myth.

But other experts disagree, including Dr. Marion Nestle, professor of nutrition, food studies, and public health at New York University (search).

"It's one thing to talk about statistics and another to talk about what's happening to individuals," she told the Times.

"Everyone notices that there are more overweight people now," Nestle said.