Long-Term Impact of Bariatric Surgery and Dietary Interventions on Weight Loss, Physical Activity, and Food Preferences.

OBJECTIVE

This study aimed to examine changes in dietary intake, physical activity, appetite, and weight following laparoscopic adjustable gastric banding (LAGB), sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and dietary intervention in adults with severe obesity.

METHODS

This prospective, nonrandomized cohort included 57 adults undergoing LAGB (n = 11), SG (n = 21), RYGB (n = 7), or dietary intervention (Diet; n = 18). Seven assessments over 36 months were analyzed using mixed-effects models.

RESULTS

During the first 12 months, energy intake declined across groups (β = -1322 kJ/visit; 95% CI: -2045, -599; p < 0.001), without between-group differences in energy or macronutrient trajectories. Vigorous activity increased following SG relative to Diet (interaction β = +10 min/day/visit; 95% CI: 0.1, 20). During 12-36 months, energy intake increased in Diet (β = +3089 kJ/visit; p < 0.001), whereas surgical groups maintained energy restriction (all interactions p ≤ 0.006). Changes in macronutrients, calcium intake, and physical activity were modest or transient, although protein intake increased after LAGB relative to Diet (interaction β = +8.6 percentage points; p = 0.006). SG produced sustained appetite reduction (p ≤ 0.013). At 36 months, weight remained 25.1%, 26.4%, and 16.9% below baseline following SG, RYGB, and LAGB, respectively.

CONCLUSIONS

Interventions demonstrated biphasic dietary and behavioral adaptation. Surgical procedures produced durable energy restriction and weight loss despite modest long-term changes in dietary composition and physical activity.

TRIAL REGISTRATION: ANZCTR: 12613000188730.