Dieting is a $40-billion-a-year business. Could it be wiped out by the discovery of a new naturally occurring hormone called obestatin that helps suppress the appetite?
In a study published Friday in the prestigious journal Science, rats injected with obestatin lost a lot of weight.
"There's no question this is hopeful," ABC News medical contributor Dr. David Katz said of the study, conducted by researchers at Stanford University and sponsored by Johnson & Johnson.
"This is a discovery and every discovery expands the frontiers of knowledge," he added. "Knowledge is power, and it could lead to new and improved weight loss treatment."
Obestatin is made in the stomach and small intestine, and reduces hunger, in part, by slowing the rate at which food travels through the stomach and the small intestine. An extra dose of obestatin could slow digestion even further.
However, as with all studies done only in animals, there's the concern that the same effects will not show up in humans.
"First we have to prove that it will work in humans," Katz said. "If that happens, then I would estimate that it will likely be a five-year process to turn the discovery into something people can use."
One big mystery in the results is that it is not known how the rats were feeling when they were on the obestatin, Katz said. Perhaps they ate less because they were nauseous (rats don't vomit, so it would be difficult to tell) and that would be a very undesirable side effect of obestatin as a weight-loss drug.
In the meantime, knowing that obesity has genetic causes may help ease the stigma against the overweight. There are more than 50 genes that control weight.
"We have to realize the tendency to gain weight is biological," Katz said. "It helps people to understand they're not to blame. For far too long, people have beat up on themselves and each other."
At the same time, Katz said, people must acknowledge that our biological makeup hasn't changed over the past 100 years, but the number of overweight and obese people has risen dramatically. So, a healthy lifestyle will remain the most important way to control weight.
"We know of many, many hormones that influence weight, but we still have to work on those old standbys -- diet and exercise," Katz said.