People taking semaglutide continued eating fewer calories after 60 weeks, even as some feelings of hunger returned.
The study suggests eating less — not just feeling less hungry — may help explain the medication's long-term weight loss benefits.
Researchers say the findings may help set realistic expectations for people taking semaglutide over the long term.
Many people who take semaglutide for weight loss notice dramatic changes early on, including feeling less hungry and thinking about food less often. But as time goes on, some worry the medication has stopped working if those effects begin to fade.
A new study from researchers at the University of Pennsylvania suggests that may not be the case. The researchers found that adults taking semaglutide continued to eat significantly fewer calories after more than a year on the medication, even though some of the early appetite-suppressing effects became less noticeable over time.
The findings, published in The American Journal of Clinical Nutrition, help explain how semaglutide may support both initial weight loss and long-term weight maintenance.
“Many patients worry that their medication has stopped working if they notice some return of hunger after the first several months,” researcher Jena S. Tronieri said in a news release.
“Our findings show that even when people feel some of those sensations returning, semaglutide continues to help them eat less. That sustained reduction in calorie intake appears to be a key reason why weight loss is maintained over time.”
How the study was conducted
The randomized, double-blind clinical trial followed 120 adults with overweight or obesity for 60 weeks. Participants were randomly assigned to receive either a once-weekly 2.4-milligram dose of semaglutide or a placebo, and everyone also received regular counseling on healthy eating and physical activity.
At the start of the study and again after 20, 40, and 60 weeks, participants completed a five-hour laboratory visit. After eating a standardized breakfast, they were offered lunch and instructed to eat until they felt comfortably full. Researchers then measured exactly how many calories each participant consumed.
The study also tracked hunger, fullness, food cravings, and how rewarding participants found different foods.
What the findings could mean
Throughout the study, people taking semaglutide consistently consumed about 24% to 30% fewer calories than those receiving the placebo. Participants in the semaglutide group also lost an average of 15.1% of their starting body weight after 60 weeks, compared with 3.4% in the placebo group.
One of the more notable findings was that the medication's effects on appetite didn't all last equally. During the first 20 weeks, participants reported feeling less hungry, having better appetite control and thinking about food less often. By weeks 40 and 60, however, many of those self-reported differences were no longer statistically significant, even though calorie intake remained substantially lower.
For consumers, that distinction may be reassuring. The researchers say a gradual return of hunger doesn't necessarily mean semaglutide has stopped working. Instead, the medication may continue helping people eat fewer calories even if it no longer feels as dramatically effective as it did during the first few months.
“This study highlights an important distinction between people’s perceptions of their appetite and how they actually eat,” researcher Thomas A. Wadden said in the release.
“People taking semaglutide for weight loss often notice dramatic reductions in hunger and food noise when they begin this treatment. If those sensations gradually become less noticeable, some may incorrectly assume the medication is no longer effective.”