Eating patterns may predict weight loss response to GLP-1 drugs, study finds

A new study on GLP-1 medications such as Ozempic and Wegovy suggests that a patient’s eating pattern can influence how much weight they lose. Researchers in Japan followed 92 adults with type 2 diabetes who were newly prescribed GLP-1s and tracked them for a year, recording changes in weight, body composition, diet, blood sugar and cholesterol, as well as eating behavior.

The researchers defined three eating patterns linked to weight gain: external eating, emotional eating and restrained eating. External eating is driven by the sight or smell of food rather than hunger, emotional eating occurs in response to stress or mood, and restrained eating involves deliberate limits on intake to lose weight. Across the cohort, most participants lost weight and body fat, with blood glucose improving as well, though cholesterol changes varied. By three months, many reported eating less in response to emotional triggers and external cues, but by year’s end emotional eating had returned toward baseline while external eating continued to decline.

In the end, external eaters—those influenced by sights and smells—lost the most weight and showed greater improvements in blood glucose than participants who struggled with emotional or overly restricted eating. “One possible explanation is that emotional eating is more strongly influenced by psychological factors, which may not be directly addressed by GLP-1 receptor agonist therapy,” said Takehiro Kato of Gifu University, the study’s second author. The senior author, Daisuke Yabe of Kyoto University, added, “Pre-treatment assessment of eating behavior patterns may help predict who will benefit most.”

GLP-1s work by mimicking a natural hormone that helps control blood sugar, slow digestion, increase feelings of fullness and dampen brain responses to food cues, all of which can curb appetite. But the study suggests these mechanisms may be less effective for people whose overeating is driven by emotional distress rather than external cues. Yabe emphasized that GLP-1s appear to be more effective for weight gain or elevated glucose when overeating is triggered by outside stimuli, rather than by internal emotional states.

“GLP-1 receptor agonists are effective for individuals who experience weight gain or elevated blood glucose levels due to overeating triggered by external stimuli,” Yabe said. “However, their effectiveness is less expected in cases where emotional eating is the primary cause.”

Outside experts note this does not mean GLP-1 drugs won’t help emotional eaters, but that medication may need to be paired with additional support to address underlying factors. Dr. Mir Ali, medical director of MemorialCare Surgical Weight Loss Center, who was not involved in the study, told Healthline that treating emotional eating may require a broader approach beyond a pharmacologic fix.

The findings could inform pre-treatment assessments in clinics prescribing GLP-1s, helping clinicians tailor plans to patients’ eating behavior patterns and potentially identify those who will benefit most from the drugs. The study adds to a broader discussion of GLP-1 use in the United States, where roughly 12% of adults have turned to these medications amid an obesity epidemic and rising interest in pharmacologic weight management.

While the exact mechanisms and long-term outcomes require further study, researchers say the work highlights the importance of considering psychological and behavioral factors when evaluating weight-loss therapies. In practice, that could mean pairing GLP-1 therapy with behavioral counseling or stress-management resources for individuals prone to emotional eating, to maximize the likelihood of meaningful and sustained results.