The Effect of Mediterranean Diet Adherence and Physical Activity Level on Weight Loss after Laparoscopic Sleeve Gastrectomy

Background Metabolic bariatric surgery is an effective method in the treatment of severe obesity; long-term weight loss success depends on the extent to which patients adapt to lifestyle changes. Mediterranean diet and physical activity are important lifestyle components for sustainable weight control. This study examines the effect of adherence to the Mediterranean diet and physical activity levels on weight loss in patients in the second year follow-up after Laparoscopic Sleeve Gastrectomy (LSG). Methods This cross-sectional and analytical study included 97 patients who underwent LSG surgery at a university hospital in Türkiye and reached the 24th-month follow-up. Data were collected using the Mediterranean Diet Adherence Screener (MEDAS) and the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Weight loss efficiency was evaluated using percentage of excess weight loss (EWL%), total weight loss (TWL%), and body mass index (BMI). Results 60.8% of the participants had moderate-high adherence to the Mediterranean diet, and 18.6% had adequate physical activity levels. The EWL% and TWL% values of those with moderate-high adherence to the Mediterranean diet were statistically significantly higher at 3, 6 and 24 months (p < 0.01). The effect of physical activity level on TWL% was significant at 18th and 24th months. The rate of weight regain in the 18–24 months period was 26.8% and this rate was associated with low dietary adherence and physical inactivity. Conclusion Adherence to the Mediterranean diet and physical activity are determining factors in the maintenance of weight loss after LSG. A multidisciplinary, patient-centered case management approach may enhance long-term outcomes.