39-LB: The Greater the Increase in Physical Activity and Exercise after Metabolic Bariatric Surgery, the Greater the Loss of Fat Mass in Obese Korean Subjects

Object: Exercise after metabolic bariatric surgery (MBS) is known to be more effective in reducing weight, maintaining muscle strength, and improving insulin sensitivity than MBS alone. In this study, we investigated the influence of increment in physical activity and exercise on clinical outcomes after MBS in obese Korean subjects.

Method: We recruited 94 patients who underwent MBS from April 2019 to December 2021 prospectively. The levels of physical activity and exercise were collected with self-report questionnaires before and 1 year after MBS. Physical activity- and exercise-related energy expenditure (MET-min/week) was calculated by multiplying the frequency, intensity, and duration of the activities. Patients were classified into non-improved and improved groups according to changes in energy expenditure relative to before surgery.

Result: The mean age was 41.4 ± 10.4 years, 38 (40.4%) were male, BMI was 36.9 [32.6, 40.6] kg/m2, and energy expenditure was 438.0 [87.0, 1105.3] MET-min/week at baseline. The improved group had significantly higher BMI (38.0 [34.4, 41.1] vs 33.2 [32.1, 38.8], P = 0.031) and lower MET-min/week (369.8 [174.0, 601.1] vs 761.3 [65.3, 1414.5] METS-min/week, P = 0.045) before surgery. The reduction of BMI and fat mass was significantly greater in the improved group compared with the non-improved group (BMI, 10.2 [8.6, 13.2] vs 9.0 [6.7, 10.9] kg/m2, P = 0.030; fat mass, 25.9 ± 11.1 vs 20.3 ± 9.6 kg, P = 0.016). However, the change in muscle mass was not different between the groups. A greater increase in MET-min/week after MBS was associated with a greater reduction in fat mass after MBS (β = -0.217, P = 0.007), but not with the change in muscle mass.

Conclusion: Patients with higher BMI and lower degree of physical activity and exercise were likely to increase their physical activity after MBS. This improvement in physical activity and exercise was associated with more fat mass loss while maintaining muscle mass.