This article is more than 5 years old. Information may no longer be current.
Food-related brain activity differed for gastric bypass, banding recipients
Recipients of Roux-en-Y gastric bypass had reduced brain-hedonic responses to food compared with gastric banding recipients and controls who did not undergo surgery in a recent study.
Researchers performed structural MRI, blood oxygen level-dependent (BOLD) functional MRI (fMRI), among patients who underwent Roux-en-Y gastric bypass (RYGB; n=30) or gastric banding (BAND; n=28), along with 25 BMI-matched, weight-stable controls. Questionnaires measuring personality, mood, eating behavior, impulsivity and reward sensitivity were administered, and surgery recipients provided self-reported, 3-day records of their eating habits.
During scanning, participants were shown images of low- and high-calorie foods, plus blurred images and pictures of household objects unrelated to food, and rated each item’s appeal. Surgery patients also received an ad libitum ice cream test meal after scanning.
Patients who received RYGB had reduced BOLD activation in multiple clusters compared with BAND recipients when viewing low- and high-calorie foods in whole-brain analysis. Functional region of interest analysis indicated lower BOLD activation across the reward system for high-calorie but not low-calorie foods. RYGB recipients rated high-calorie foods less appealing than other group members, while low-calorie foods and nonfoods were rated similarly.
Both surgical groups reported similar ratings of hunger, volume of food they could eat and pleasantness to eat evaluated foods during scanning and provided lower values than controls. During the post-scanning test meal, the RYGB group rated the ice cream less pleasant to eat than BAND recipients (P=.047), although consumption was similar (P=.54).
Analysis of dietary records indicated a reduced percentage of fat-derived energy in the RYGB group vs. the BAND group. Patient responses to behavior questionnaires also indicated healthier eating habits and reduced eating disorder psychopathology among RYGB recipients compared with the other groups.
“RYGB and BAND surgical treatments for obesity are distinct in their mechanisms of weight loss,” the researchers wrote. “Postoperatively, patients have reduced hunger after both procedures, but there are lower brain hedonic and exaggerated gut hormone and bile acid responses to food after RYGB that would explain its greater efficacy for weight loss.”
Disclosure: The researchers report no relevant financial disclosures.