Weight-loss drug craze appears to be curbing US obesity epidemic

For the first time in a decade, obesity in the U.S. is declining — and a new study suggests it's because of wildly popular medications such as Ozempic. 

The number of obese Americans has been steadily climbing for years, and the country's average body mass index, or BMI, has been creeping up along with it. But in 2023, something changed: Obesity levels fell to 43.96% from 44.1% the year prior. It's a small decline, but a meaningful one, researchers say. The biggest change occurred in the South, according to the analysis, which also had the highest concentration of prescriptions written for the drugs.

The findings, published Friday in JAMA Health Forum, suggest that blockbuster medications such as Novo Nordisk A/S's Ozempic and Wegovy and Eli Lilly's Mounjaro and Zepbound may actually be starting to move the needle on America's obesity epidemic. 

"We're already seeing the impact in the data," Benjamin Rader, the computational epidemiologist at Boston Children's Hospital who led the study, said in an interview. 

Read more:  Employees need more than GLP-1s to manage their weight 

Rader and his colleagues analyzed electronic health records and de-identified insurance claims from millions of American adults to track the prevalence of obesity over the last decade. They used the claims data to map prescriptions for drugs such as Ozempic and Mounjaro, part of a class of medications known as GLP-1s. 

Millions of Americans struggle with obesity, which is known to increase the risk of dangerous health conditions including diabetes, heart disease and cancer. The rising percentage of overweight and obese Americans is expected to strain the health-care system and boost medical costs significantly over the next quarter century if the trend doesn't reverse, according to a recent study in The Lancet medical journal.

Safe and effective weight-loss medications have the potential to change that trajectory, experts said, but their use has been hampered by widespread supply shortages and high prices that hinder access. Even with those challenges, the drugs are starting to have an impact, Rader said. 

"While obesity remains a considerable public health concern, the observed reductions in obesity prevalence suggest an encouraging reversal from long-standing prior increases," the researchers wrote. 

Read more:  Do your employees need Ozempic? How to include GLP-1s in your health plans

The drug's impact was most obvious in the South, where obesity rates dropped to 45% from 46% the year prior. In that region, 6% of residents on average received a prescription for weight-loss and diabetes drugs compared to 5.1% of those in the Midwest, 4.4% in the Northeast and 3.4% in the West.

Obesity rates in other regions were flat — except for the West, where they ticked up. 

The researchers cautioned that the South experienced a disproportionately high number of deaths from Covid-19 among individuals with obesity, which could have impacted their findings. However, the highest number of Covid deaths occurred prior to 2023, so it wouldn't explain the entire decline, they said.

Rader expects to see reductions in obesity-related health conditions such as cardiovascular disease as access to the drugs improves. Currently, fewer than 20 state Medicaid programs cover them for weight-loss. Medicare, the government health plan for older Americans, doesn't currently cover weight-loss drugs — though a proposal from the Biden administration could soon change that. About 60% of employers have opted to cover the shots for their employees.