The answer may depend on which doctor you see.
"I'll probably take a wait-and-see attitude myself," said Greg Anderson, an assistant professor of family medicine at the Mayo Clinic. "The track record has not been particularly good for diet medications."
By contrast, Dr. Albert Levy, assistant professor of medicine at the Mount Sinai School of Medicine, said he has already been prescribing the same combination of drugs in the newest offering off-label for two years, a decision based on data from previous clinical trials. He said almost all of his patients lost weight when they were given the medications.
"Once the patient has learned how to control the appetite and has lost a good amount of weight, she or he is stimulated to continue to lose weight without the medications," Levy said.
The two medications in question are Belviq and Qsymia. Belviq, which contains a new medication called lorcaserin, was approved June 27. Qsymia, approved earlier this week, is a combination of two medications which had already been on the market, phentermine and topiramate.
In trials, patients taking Belviq lost about 5 percent of their total weight, while studies showed those on Qsymia lost about 10 percent of their weight. Dramatic, they are not. Still, many are hopeful that these medications will help millions of Americans deal with obesity and related conditions like heart disease, hypertension and diabetes.
Investors are banking on these drugs too. The U.S. weight loss market is estimated to be worth more than $60 billion per year. Stocks for manufacturers of both drugs jumped at the news of the drugs' approval. Analysts predict that Belviq and Qsymia sales can reach $1 billion annually.
But that's only if doctors prescribe them. Ultimately, primary care physicians will be the gatekeepers who determine the fate of these medications. Will they turn to a simpler remedy for obesity than urging their patients to eat right and exercise? Or will they view these medications as more trouble than they're worth?
"I will predict that neither will be on the market in five years," said Dr. Lee Green, professor and chair of family medicine at the University of Alberta. "They really just don't do that much.
"'Up to 10 percent weight loss' sounds great, until you look closely. That's when used by selected volunteer patients in carefully designed, closely monitored clinical trials. We'll be lucky to get half that in the real world."
Levy, meanwhile, said he would likely use Qsymia. He said he had previously been using the component medications of the new drug for only a month at a time. Given the FDA's approval for longer use, though, he said he would now consider the medication for extended periods. He said he was less comfortable with Belviq and might consider using it after it had been out longer.
Dr. Heather Agee, a general internist and office medical director at Johns Hopkins Bayview, said that she used to prescribe phentermine regularly for weight loss; "It was very effective as an appetite suppressant," she said. Yet, she said she stopped prescribing it because "I found that people didn't make the lifestyle changes and gained the weight back."