A promising drug that curbs food cravings has been found to help users lose weight and raise good cholesterol. But researchers are cautioning that it is not a miracle drug.

A new Canadian study shows that rimonabant will likely become a new contender in the war against obesity by helping patients lose dangerous abdominal fat and reduce the risk factors than can lead to heart disease and diabetes.

Though it is not available yet, the drug will be marketed as Acomplia if it receives regulatory approval.

In a double-blind, placebo-controlled study of more than 1,000 overweight or obese patients, rimonabant, at its highest dose, produced a weight loss of an average 15 pounds (6.7 kg) over a year.

Patients on the higher dose of the drug were far more successful in losing weight and maintaining that weight loss than patients on the lower dose or in the placebo control group.

But more important, say researchers, the drug helped reduced fat around the waist, increased good cholesterol, lowered signs of inflammation in the blood vessels, and improved the body's ability to handle insulin.

That's important, since abdominal fat -- particularly combined with high cholesterol -- has been found to play a more important role than overall excess weight in the development of cardiovascular disease and diabetes.

The study will be published in this week's issue of the New England Journal of Medicine.

The lead researcher in the study, Dr. Jean Paul Despres of the Quebec Heart Institute in Quebec City, says the drug would not be for everyone; only those at the greatest risk of the dangers of obesity.

"We are not interested in developing a drug for cosmetic weight loss," he says. "We want to save heart attacks, we want to save cases of diabetes."

"Once you are dealing with an individual who is a time bomb for heart disease and diabetes, hopefully this drug would be appropriately used to target the root cause of the elevated risk."

Mary Melton used rimonabant as part of the study and found it worked well for her. She gradually lost more than 30 pounds over two years by taking the drug and sticking to a good, low-calorie diet.

"Oh, I liked it. It really worked," the Ontario woman says. "I felt better; I liked the way I look. I felt I could be prouder of myself, I felt better I looked better."

Rimonabant works by stopping patients from craving food. It blocks signals in the brain that appear to produce the urge to eat, allowing people to lose their cravings. That's what Mary noticed.

"You ate only because it was breakfast, lunch, or dinner," she says. "You never had that urge to grab anything between meals."

But she also noticed that her cravings returned after she went off the drug.

"I'd be the No. 1 candidate to go back on it again if they'd bring it out again, that's for sure," she says.

The road to weight loss has been strewn with drugs over the years that at first showed promise and then after prolonged use, were found to produce serious side effects. The drug fen-phen, sold under the name Redux, was pulled from the market in 1997 after research revealed it caused heart valve disease.

Even with rimonabant, 40 per cent of study participants dropped out, complaining of the side effects of anxiety and nausea.

Doctors say that isn't unusual for weight loss drugs, none of which are perfect.

"We don't really have a lot of anti-obesity medications right now," says Dr. Arya Sharma of Hamilton General Hospital. "There are two drugs on the market, and many patients cannot take these drugs for various reasons. And so the more drugs that we have to manage medical obesity, the better for our patients."

But as promising as rimonabant is, it's not a miracle drug, Despres cautions.

"Rimonabant should not be seen as a fix for the epidemic of obesity in Canada," he says.