A cross-sectional study published in Physiology & Behavior reports that adults with obesity using GLP-1 receptor agonists had higher sweet taste detection thresholds and lower food noise scores than people eligible for the drugs but not yet taking them. Most other chemosensory measures the researchers tested looked much the same across groups.

GLP-1 receptor agonists are the drug class that includes semaglutide and tirzepatide, prescribed for obesity and type 2 diabetes. They reduce energy intake and produce clinically meaningful weight loss, but the authors note that the chemosensory and behavioral contributions to that effect remain poorly characterized, which is the gap this study set out to probe.

How the groups were split

The researchers recruited 79 adults with obesity and sorted them into three groups: 27 pre-use participants eligible for treatment but not yet on it, 25 who had been using a GLP-1RA for one month, and 27 who had been using one for six months. Nobody was followed over time, so these are three different sets of people compared at a single point.

Participants ran through laboratory assessments of taste detection thresholds, suprathreshold intensity, taste hedonics, fat taste, chemesthesis, olfactory function, and cephalic-phase salivary response. Questionnaires covered food noise, cue responsivity, cravings, and food reward, with diet captured using the ASA24 24-hour recall tool.

Key results

Sweet taste detection thresholds differed by group (p=0.001), with higher thresholds in both the one-month (p=0.0078) and six-month (p=0.0024) groups compared with pre-use controls. Other taste qualities shifted in the same direction but did not reach significance, and intensity ratings, hedonics, olfaction and chemesthesis were largely unchanged apart from a limited fat-intensity difference at one linoleic acid concentration.

Food Noise Questionnaire scores were lower in six-month users than in pre-use controls (P = .026). That group also showed lower cue responsivity, craving, food reward and energy intake, while protein intake did not significantly differ across groups.

Limitations

This is a cross-sectional design with 79 participants split three ways, so no participant was tracked from before treatment to six months in, and the study cannot establish that the drugs caused the differences. The authors frame the findings as associations throughout, and the directional shifts in taste qualities other than sweet did not reach significance.

Bottom line

The interesting result here is how narrow the chemosensory effect was: one taste quality moved, and the rest of the sensory battery mostly did not. What changed more consistently was the behavioral side, food salience and reward, which is where the next study, ideally longitudinal, should look.