Adherence to Dietary Behavior Recommendations Moderates the Effect Between Time Since Metabolic and Bariatric Surgery and Percentage Total Weight Loss

Metabolic and bariatric surgery (MBS) is the gold standard in treating severe obesity. Previous research implies that different psychological and behavior-related factors might be critical for MBS’ sustained success. Yet adherence to dietary behavior recommendations and its impact on weight development is rarely examined. This study investigated the relationship between adherence to dietary behavior recommendations and the percentage of total weight loss (%TWL) after MBS.

This study is a cohort study (acquisition in Germany). N = 485 patients after MBS, being in grade III of obesity (body mass index (BMI) ≥ 40 kg/m²) pre-MBS, were included. Participants answered a standardized assessment on the relevant constructs, including adherence to dietary behavior recommendations, depression symptoms, weight, diet, and MBS characteristics.

BMI pre-MBS, type of MBS, age, regularity of physical activity, and depression symptoms were identified as significant covariates of %TWL and adherence. Within 6 months after MBS, adherence seems to peak, F_(5,352) = 12.35, p < .001. Adherence and time since MBS predict %TWL. A higher adherence (moderator) is related to a higher %TWL, R² = 52.65%, F_(13,344) = 31.54, p < .001.

After MBS, adherence to dietary behavior recommendations seems crucial for maximizing its success. Implications for the optimization of MBS’ success in aftercare management arise. In particular, behavior modification interventions should be routinely implemented.