OBJECTIVES: This systematic review and meta-analysis is based on randomized controlled trials evaluating the effect of physical activity on weight loss in adults undergoing bariatric surgery. The study compared certain biomarkers for individuals with and without physical activity after bariatric surgery. Secondary, the study identified potential successful interventions for the target population. METHOD: PubMed, Embase, OVID, CINAHL, and Cochrane Library were searched from January 2000 to December 2020. Intervention studies on the effect of physical activity in adults after bariatric surgery were selected, included, and analyzed following the PRISMA guidelines. The primary outcome was weight loss followed by selected biomarkers. RESULTS: Two independent reviewers extracted data and conducted quality assessments. Of the 11 studies included, six reported BMI, two reported fat-free mass, three reported fat mass, two reported waist-hip ratio, and two reported waist circumference. Six studies measuring change from baseline BMI reported a significant intervention effect: SMD = -0.93 (-1.65;-0.20) with high heterogeneity of included trials (I2 = 72%). There was no significant difference between control and intervention groups for other outcomes. CONCLUSION: BMI as a measure of physical activity positively impacts the target population. Large-scale studies with better criteria and a longer evaluation follow-up may finalize pronounced outcomes.