What the Study Measured
A question that comes up constantly in weight management clinics now has a direct measurement behind it: if the hunger comes back, has the drug stopped working?
Penn Medicine researchers ran a 60-week trial in 120 adults who were overweight or had obesity, assigning them to once-weekly semaglutide at 2.4 mg or placebo, with regular lifestyle counseling in both groups. The design’s strength is that it did not rely on what people said about their appetite. It measured what they ate.
At baseline and again at weeks 20, 40, and 60, participants completed a five-hour laboratory assessment. After a standardized breakfast, they were offered lunch and told to eat until they felt comfortably full. Researchers weighed and counted the calories consumed.
Across those follow-up assessments through week 60, participants taking semaglutide ate about 24 to 30 percent fewer calories than those on placebo, according to Penn Medicine. Weight followed. The semaglutide group lost an average of 15.1 percent of initial body weight at week 60, against 3.4 percent for placebo.
The Gap Between Feeling Hungry and Eating More
The finding that makes this study useful is the mismatch between what people reported and what they did.
During the first 20 weeks, participants on semaglutide reported less hunger, greater appetite control and fewer thoughts about food, the sensation many patients call food noise. By weeks 40 and 60, the differences between the semaglutide and placebo groups on many of those subjective measures were no longer statistically significant.
The calorie difference persisted anyway.
“This study highlights an important distinction between people’s perceptions of their appetite and how they actually eat,” said Thomas A. Wadden, PhD, a professor of psychology in psychiatry and former director of Penn’s Center for Weight and Eating Disorders. “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.“
Lead author Jena S. Tronieri, PhD, a senior research investigator at the center, framed the practical consequence directly. “Many patients worry that their medication has stopped working if they notice some return of hunger after the first several months,” she said. “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.“
There is a plausible explanation for the divergence that the study does not settle. Subjective hunger ratings are relative to a person’s own recent experience, and a body 15 percent lighter has different baseline sensations than it did a year earlier. Feeling hungrier than you did at week four is not the same as eating as you did before treatment.
What This Does Not Tell You
Several limits deserve to sit here rather than at the end, because they bound what the result can be used for.
The single largest one is that this study says nothing about stopping. Every participant analyzed was on treatment. It does not measure what happens to calorie intake after discontinuation, which is the question behind most of the current anxiety about these drugs. Separate research has consistently found weight regain after stopping.
The sample was 120 people. That is adequate for a controlled laboratory feeding study and small for drawing conclusions about population-level behavior. The trial also ran 60 weeks, so it does not describe year three or year five.
The laboratory meal is a proxy, not real life. Participants ate a standardized breakfast in a research setting and then a single test lunch under observation. That design controls variables well and does not capture evening eating, weekend eating, restaurant portions, stress eating or the social context in which most calories are actually consumed.
Both groups received lifestyle counseling throughout, so the comparison is semaglutide plus counseling against placebo plus counseling, not against no intervention.
The study was supported in part by a Novo Nordisk research grant through the company’s Investigator Sponsored Studies Program. Penn states that Novo Nordisk played no part in the conception, conduct, analysis, or reporting of the study.
Why It Matters for People Considering Stopping
The clinical relevance here is a decision, not a data point.
Patients who conclude their medication has quit working sometimes stop taking it, sometimes stop refilling because they no longer see the point of the cost, and sometimes ask for a dose increase they may not need. This study suggests at least one of those inferences may rest on a misreading of the evidence available to the patient, which is their own sense of hunger.
“Our results suggest that patients may experience a partial return of appetite sensations over time, without losing the medication’s benefit of continuing to reduce calorie intake, which is needed to maintain their new, lower body weight,” Tronieri said. “Understanding that can help set realistic expectations and may encourage people to stay on treatment long term, as approved by the U.S. Food and Drug Administration and recommended by the treatment guidelines of numerous professional societies.”
That framing comes from researchers whose work is partly industry-funded, and readers should weigh it accordingly. It is also consistent with how obesity is defined in current clinical guidance, as a chronic condition managed rather than cured.
What Patients Should Take From It
Nobody should start, stop or change a dose based on this study, and the most useful action it supports is a conversation rather than a decision.
If your hunger has returned somewhat after several months on semaglutide, that is a documented pattern and not automatically a sign of treatment failure. Weight trajectory, waist measurement, blood pressure, lipids and glucose are more reliable indicators of whether the medication is doing its job than the subjective sense of appetite.
If weight has plateaued or is climbing, that is worth raising with a prescriber, who can look at dose, adherence, other medications, sleep, alcohol and activity before concluding anything about the drug.
Anyone considering stopping because of cost, side effects, or coverage changes should have that conversation before stopping rather than after, since abrupt discontinuation carries a well-documented pattern of regain.
The next questions researchers will need to answer are what calorie intake looks like beyond 60 weeks, what it looks like after discontinuation, and whether the same pattern holds for tirzepatide and the newer oral agents. MedicalDaily will report follow-up analyses as they publish.
Frequently Asked Questions
What did the study find? Adults taking semaglutide ate 24 to 30 percent fewer calories than those on placebo at laboratory assessments through week 60, and lost 15.1 percent of body weight versus 3.4 percent.
Does hunger really come back? Reported hunger, appetite control and food noise differed clearly from placebo at 20 weeks, but many of those differences were no longer statistically significant by weeks 40 and 60.
So has the drug stopped working if I feel hungrier? Not necessarily. In this trial, calorie intake stayed lower even as subjective appetite differences faded. Weight trend is a better indicator than hunger.
How big was the study? 120 adults with overweight or obesity, over 60 weeks.
Does this tell me what happens if I stop? No. Everyone analyzed was on treatment. The study does not address discontinuation.
Who funded it? It was supported in part by a Novo Nordisk research grant. Penn states the company had no role in the study’s conception, conduct, analysis or reporting.
Should I change my dose? Not on your own. Discuss weight trajectory and any concerns with your prescriber.