Eat Ice Cream, Burgers and Pizza and Still Lose Weight?

'No Magic Bullet'

But was Sensa peer-reviewed?

Sensa, a supplement that claims to be proven to help you lose weight, is sprinkled on food.

(ABC News)

"20/20" showed Hirsch's study to professor Barker Bausell at the University of Maryland. He is one of the nation's foremost authorities on clinical studies and the author of a book on medical exaggeration.

Bausell said that Hirsch's research "has a negative value." It hasn't been published in a major medical journal, although Hirsch says it will be.

"It takes a long time after you complete studies to go through all the data analysis and write it," Hirsch said.

But the Endocrine Society, which Hirsh says reviewed and approved of his work, said they merely invited him to present his findings for debate. And they were "surprised and troubled by the promotional nature of his presentation."

Dr. Pamela Peeke, a clinical professor of medicine at the University of Maryland and the host of Fit for Life, says there is no scientific proof that Sensa works and believes the study was done to justify a commercial product.

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"There's no magic bullet and there's no magic sprinkle," she said. "This isn't a diet. This is just another pet rock."

Hirsch said he would eventually have a finalized study that a journal would accept, but in the meantime he cannot turn his back on people who need to lose weight.

"When you talk to patients who've lost 30, 40, 50 pounds and you see and talk to them and they call you back and they say, gee you know their life has changed, it's a wonderful thing," he said, "and it's really not fair not to let people have this."

A Mistake

Hirsch provided "20/20" with a handful of happy customers, including one man who claimed he lost 120 pounds.

"You know there is a very interesting plaque I once saw at the National Institutes of Health," Peeke said. "It said in God we trust, everyone else must show data. People believe what they want to believe."

Especially when the people in the Hirsch study weighed themselves and reported their own weight losses with no outside checks.

"When you cannot monitor and supervise participants in a trial, that's a big problem because people will report what people will report," Peeke said.