BOSTON -- A new diet drug is showing promising results. It's a blend of two very well-known drugs.

As NewsCenter 5's Heather Unruh reported Monday, the combination could get federal approval.

Obesity is an epidemic in America. For so many, finding the best way to lose weight is a constant struggle.

"Most people who lose weight gain it back and there's a good reason why it's not about their willpower," said Dr. Carolyn Apovian, the director of the nutrition and weight management program for Boston Medical Center. "We know that some people genetically are programmed to be obese."

Apovian is a weight loss expert who has investigated many popular diet drugs, including ALLI and Xenical. Most recently she studied a potential new option. Contrave is the first-of-its-kind diet drug to target food addiction. It's a combination of two drugs, an anti-depressant and an anti-addiction drug. Both are already on the market.

"So we have a good idea of the safety of these drugs," Apovian said.

While studies show there are some side effects, including nausea, constipation, and headache, there's evidence the one-two punch in Contrave can help people lose weight. Some who took it lost 5-10 percent of their body weight. The most obese patients lost much more.

"Almost parallel to what you would see with patients undergoing gastric bypass 30 percent weight loss to 40 percent weight loss," Apovian said.

The results actually exceeded the U.S. Food and Drug Administrations requirements to prove the drug is effective at helping people lose weight. However, some weight loss specialists like, Dr. Lee Kaplan of Massachusetts General Hospital, are somewhat cautious.

"I think there will be a small subset of patients for whom this drug is be exactly what the doctored ordered. I think for the vast majority it's going to be a moderate effect, if any effect," said Dr. Lee Kaplan, director of the MGH Weight Center.

For full disclosure, Apovian is on the advisory board for Orexigen Therapeutics, the company that developed Contrave.