Bariatric Surgery may Change Eating Behavior

Dr Setu Gupta, Endocrinologist & Diabetologist, Sir Ganga Ram Hospital, New Delhi

Bariatric surgery reduces food intake mainly by increasing satiety and reducing meal size and eating rate, while evidence for similar effects with obesity medicines is still limited.

Obesity is a chronic disease influenced by genetic, hormonal, behavioral, and environmental factors. Eating behavior is also different in people with obesity, who may have greater food cravings, stronger responses to palatable foods, larger meal sizes, faster eating rates, and delayed feelings of fullness. This review examined objective measures of eating behavior to understand how bariatric surgery and obesity medicines affect food intake and eating patterns.

The review found that Roux-en-Y gastric bypass and sleeve gastrectomy consistently reduced total energy intake. These changes were mainly related to smaller meals and slower eating rates, without consistent changes in when meals were started or in the types of macronutrients selected.

Some smaller studies reported changes in food choices after surgery. However, these changes were not consistent across studies and were associated with greater weight loss in the cohorts where they were observed. Overall, the findings suggest that people may eat less of the same types of food after bariatric surgery rather than changing their food choices substantially.

GLP-1-based therapies were also found to reduce energy intake and improve appetite-related behaviors. Naltrexone/bupropion was described as acting mainly on central reward pathways. However, the review noted that direct evidence on how obesity medicines change eating behavior is still limited compared with the evidence available for bariatric surgery.

Overall, the review suggests that bariatric surgery reduces food intake through changes in satiety and eating behavior, including increased satiety signaling and reduced food reward responses. Similar effects may occur with obesity medicines, but more objective research is needed to determine whether they also lead to eating less of the same foods rather than changing food choices.

(Reference: Contreras Hernández F, Villelabeitia I, Levine I, le Roux CW, Miras AD, Price RK. Effects of Bariatric Surgery and Obesity Medicines on Human Eating Behavior. Annual Review of Nutrition. 2026 May 15;46.)