Metabolic and bariatric surgery MBS is a pivotal intervention for severe obesity and its comorbidities. However the significant loss of lean body mass and the associated risk of sarcopenia following surgery present major challenges to long-term patient health. The review aims to systematically summarize the dynamic changes in body composition following MBS and to discuss scientific management strategies focused on optimizing body composition. Ideal postoperative management should go beyond short - term improvements in weight and metabolic parameters it should be based on scientific principles striving to minimize fat mass particularly visceral adipose tissue while preserving or even increasing lean body mass. Achieving this goal hinges on implementing a multidimensional personalized and sustained comprehensive intervention strategy. The core components of this strategy include phased and adequate protein supplementation to stimulate muscle protein synthesis and mitigate lean tissue loss personalized exercise prescriptions combining resistance and aerobic training to synergistically promote muscle anabolism improve insulin sensitivity and prevent weight regain and a long - term multidisciplinary follow - up model that integrates expertise from nutrition physical rehabilitation endocrinology and surgical team to provide continuous patient support and education thereby ensuring long - term adherence. In conclusion implementing this body composition-focused management framework is critical for consolidating the lasting benefits of surgery and enhancing overall metabolic health and quality of life.