Kunal Shah, an assistant professor of endocrinology at Rutgers University’s Robert Wood Johnson Medical School specializing in the treatment of obesity for more than a decade, sees reason for hope in newly approved diabetes medications hitting the market.

Obesity rates have climbed steadily over the years: The Centers for Disease Control estimate about 42 percent of American adults are obese. Shah discusses Victoza (liraglutide) and Wegovy (semaglutide), two medications developed to treat Type 2 diabetes that recently have been approved to treat obesity. He also discusses a third diabetes drug, Mounjaro (tirzepatide), that has produced positive results in a trial against obesity.

What constitutes an effective obesity treatment?
The ideal is obviously to eliminate all the excess weight, but any weight reduction greater than 5 percent provides clinically meaningful benefits like lowering the risk of heart attack and other cardiovascular issues.

Did effective medical treatments exist before the diabetes drugs arrived?
Yes, both Qsymia, which helps people control cravings, and Contrave, which speeds up the metabolism, typically reduce weight by about 7 percent but different drawbacks make them unsuitable for many patients.

What diabetes drugs are currently available for the treatment of obesity?
The two that have been approved so far are Victoza (liraglutide) and Wegovy (semaglutide). Both are more effective and better tolerated than older medications, but semaglutide is probably the better drug for most people. It tends to induce greater weight loss — up to 15 percent of body weight — and it’s a weekly rather than a daily injection.

What new drugs are likely to be approved soon?
Final-stage trial results that were just published in The New England Journal of Medicine showed that a 15-milligram weekly injection of the diabetes drug tirzepatide caused patients to lose an average of 20 percent of their body weight.

How big a deal is that?
That’s a game-changer. That’s the sort of weight loss you’d typically associate with surgery. It’s not enough to eliminate all excess weight, but it’s enough to bring most obese people into the merely overweight category and eliminate most of their weight-related health risks.

What side effects do these drugs produce?
Many people suffer gastrointestinal distress when they begin treatment, but it typically goes away.

Will most obese people be taking one of these medications in a few years?
They probably should be already.

Why aren’t they?
Two reasons: First, the primary care doctors who treat most patients for obesity and everything else are not yet comfortable prescribing them. Specialists like me need to do a better job educating primary care doctors about how safe and effective they are.

Second, these medications are expensive, and although most insurers seem to be covering them for diabetes, they balk at covering them for obesity alone. Most insurers won’t cover any obesity medication unless patients can prove that they have been following a diet and exercise program for at least three months.

So, these treatments are in addition to — rather than instead of — diet and exercise?
Sadly, yes. There’s no magic thin medication yet. You can still out-eat any treatment, including a gastric bypass. But these medications help greatly, enough that they could significantly reduce obesity.