They point to studies showing that even modest weight loss — what might be considered just a drop in the bucket when measured against a person's total weight — can have surprisingly large effects. A 10% drop in weight can reduce the risk for Type 2 diabetes, lower blood pressure and help counter other problems such as sleep apnea and high blood cholesterol.
They say that a diet medication could be the catalyst needed to jump-start a successful weight loss program. "In my office a patient will come in and say, 'You know, doctor, I've lost some weight through diet and exercise, but I need something to help me kick-start [a serious weight loss program],'" said Dr. Ken Fujioka, director of nutrition and metabolic research at the Scripps Clinic in San Diego.
And they note that while several studies show that diet and exercise can produce about the same weight-loss percentages as medication, such programs — which can include supervised fitness instruction and pre-made meals — may not be realistic or affordable for most people, let alone viable for the long haul.
"When you look at interventions, they're done with volunteers and there are all kinds of people on the team, like psychologists and trainers," said Dr. Arya Sharma, professor of medicine at the University of Alberta in Canada. "You'll see the lengths they go to keep people motivated, and in the end they may get 3% to 5% weight loss."
Finally, most people can't maintain significant weight loss for more than a year or two through diet and exercise alone in part because the body kicks into a starvation mode and begins to conserve energy. Getting around this thorny problem has become one of the most significant scientific questions in the field — and may possibly, say obesity specialists, be a place where diet pills could help.
Some, such as Dr. Sidney Wolfe, director of the not-for-profit health research group Public Citizen, feel that more caution — not less — is in order when assessing these drugs. Contrave "is another drug that increases blood pressure and pulse, and it's possibly going to be approved — and that is a huge mistake. Losing weight is meaningless if it is nullified by increasing cardiovascular risks."
Wolfe knows that some doctors are frustrated by a lack of obesity medications. But that, he said, isn't justification for approving drugs that may have serious side effects. "If the overall benefits are outweighed by the risks, that's it. The FDA is part of the public health service, and we have to be aware that if they approve a drug, a doctor can prescribe it … why would any doctor want to prescribe a drug like that?"
But obesity experts argue that risks can be managed. In a September statement to the FDA advisory panel regarding Meridia and the increased risk of cardiovascular events, officials from the Obesity Society noted that "the drug is intended for use in patients who do not have established cardiovascular disease." They note that other medications for serious disorders have been approved despite known adverse side effects.
It certainly makes sense to carefully scrutinize potential health risks of any new obesity medication, especially because they have to be taken for a year or even longer, Ryan said. But diet drugs should not be held to a higher safety standard than other types of medications.
"Safety is important," Ryan said. "That is not to say that they have to be as safe as water."