Psychological aspects of eating behavior as predictors of 10-y weight changes after surgical and conventional treatment of severe obesity: results from the Swedish Obese Subjects intervention study.

BACKGROUND There is a need for a better understanding of the factors that influence long-term weight outcomes after bariatric surgery. OBJECTIVE We examined whether pretreatment and posttreatment levels of cognitive restraint, disinhibition, and hunger and 1-y changes in these eating behaviors predict short- and long-term weight changes after surgical and conventional treatments of severe obesity. DESIGN Participants were from an ongoing, matched (nonrandomized) prospective intervention trial of the Swedish Obese Subjects (SOS) study. The current analyses included 2010 obese subjects who underwent bariatric surgery and 1916 contemporaneously matched obese controls who received conventional treatment. Physical measurements (e.g., weight and height) and questionnaires (e.g., Three-Factor Eating Questionnaire) were completed before the intervention and 0.5, 1, 2, 3, 4, 6, 8, and 10 y after the start of the treatment. Structural equation modeling was used as the main analytic strategy. RESULTS The surgery group lost more weight and reported greater decreases in disinhibition and hunger at 1- and 10-y follow-ups (all P < 0.001 in both sexes) than the control group did. Pretreatment eating behaviors were unrelated to subsequent weight changes in surgically treated patients. However, patients who had lower levels of 6-mo and 1-y disinhibition and hunger (β = 0.13-0.29, P < 0.01 in men; β = 0.11-0.28, P < 0.001 in women) and experienced larger 1-y decreases in these behaviors (β = 0.31-0.48, P < 0.001 in men; β = 0.24-0.51, P < 0.001 in women) lost more weight 2, 6, and 10 y after surgery. In control patients, larger 1-y increases in cognitive restraint predicted a greater 2-y weight loss in both sexes. CONCLUSION A higher tendency to eat in response to various internal and external cues shortly after surgery predicted less-successful short- and long-term weight outcomes, making postoperative susceptibility for uncontrolled eating an important indicator of targeted interventions.