The trend: Obesity rates in the US are dropping slightly, down from 42.3% in 2021 to 40.7% in the first quarter of 2026, according to the latest Epic Research tracking data. Epic’s previous research showed obesity rates among US adults climbing from 40% in 2010 to 45% in 2020.

Why it matters: Declining obesity rates are partly attributable to increased prescribing and use of GLP-1 weight loss drugs, which rose 22% over the past two years, according to Epic tracking data. 12% of US adults currently take a GLP-1 medication for weight loss or chronic conditions, and 18% have tried one at some point, per October KFF health tracking data.

At the same time, the decline in obesity rates has been modest so far, with the broader impact of GLP-1 drugs tempered by high costs, uneven access, and the time required for increased adoption to translate into population-level outcomes.

Cost remains a major hurdle for GLP-1 users. More than half of GLP-1 users (56%) say the drugs are difficult to afford, according to KFF. And among adults who’ve ever taken GLP-1, cost was one of the most common reasons for discontinuing, at 14%. Access is also constrained by limited insurance coverage—just 19% of employers covered GLP-1s for weight loss in 2025, per an October Petersen-KFF analysis.

Duration on medication may be another factor slowing the impact on obesity rates. Clinical trials for Eli Lilly's and Novo Nordisk's GLP-1 weight loss drugs track average weight loss over more than a year or longer, meaning the 15% to 20% reductions in total body weight reported are achieved gradually. But most patients drop off the drugs before one year: Among GLP-1 patients with obesity who fill their first prescription, just 32% are still taking their medication 13 months later, per November IQVIA analysis.

Implications for GLP-1 marketers: The Epic data confirms that obesity rates are slowly trending down—the CDC also noted obesity rate modest decreases from 2021 to 2023—but the pace of change puts pressure on drugmakers to prove they can deliver meaningful public health improvements. For marketers, the next phase of GLP-1 growth will depend not only on attracting new patients but also on supporting patient access, adherence, and long-term engagement with treatment.