People who set personal weight loss targets before starting a GLP-1 medication lost more weight than those who did not, according to new research presented at ENDO 2026, an endocrinology conference held June 13 through 16 in Chicago.
The study analyzed data from 80,942 individuals with an average age of 43 who had just begun treatment with tirzepatide, the active ingredient in the medications Zepbound and Mounjaro. Researchers focused on people without pre-existing conditions such as type 2 diabetes. Of the initial group, 21,490 reached a six-month follow-up point, and 4,429 were included at 12 months. Most participants were still accruing follow-up time at the time of the presentation.
The results have not yet been published in a peer-reviewed journal.
Researchers found that females were significantly more likely than males to achieve a 20% total body weight loss by the 12-month follow-up. Individuals who set a baseline weight loss goal and had previously attempted structured diet plans also achieved a higher percentage of weight loss overall.
According to Healthline, Mir Ali, MD, medical director of the MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California, said the findings matched his clinical experience. Ali was not involved in the study. "I have found that patients who set realistic goals and actively work toward them through dietary and lifestyle changes are more likely to see significant benefits from weight loss medications," he said.
Psychologists who reviewed the findings pointed to existing behavioral science as an explanation. Nicole Andreoli, PhD, a licensed psychologist with Pathway Psychological Services in New York, said the connection between goal-setting and outcomes is consistent with what researchers already know about human motivation. Andreoli was not involved in the study.
"While the GLP-1 medications can help with the biological aspects of appetite and food noise, goal setting helps with the behavioral pieces, such as monitoring progress, making intentional choices, and maintaining co," she said, as reported by Healthline.
Andreoli added that setting goals provides direction, can help focus attention, and can help people maintain commitment and motivation.
The findings suggest that combining the pharmacological effects of GLP-1 medications with structured behavioral strategies may produce stronger results than medication alone. The sex-specific differences in outcomes also point to what researchers described as possible biological differences in how men and women respond to tirzepatide, though the study did not explain the mechanism behind that gap.
