Objective:To evaluate the potential effects of serum lipid levels, appendicular skeletal muscle mass index (ASMI) and body mass index (BMI), together with its dynamic changes, on tumor progression in renal clear cell carcinoma patients, so as to inform body weight management.Methods:This prospective cohort study included a total of 100 patients with high-risk clear cell renal cell carcinoma. Serum lipid levels were detected, ASMI and BMI were measured using bioelectrical impedance analysis and the dynamic changes of BMI were tracked. The effects of BMI, ASMI and serum lipid levels on tumor progression within 2 years were explored.Results:Patients with normal BMI and low ASMI had 5.248 (95% CI: 1.946 to 14.153, P = 0.001) times higher risk of tumor progression than those who were overweight or obese. For every 0.1-unit increase in pre-operative HDL-C, the risk of tumor progression decreased by 0.771 (95% CI: 0.631 to 0.942, P = 0.011) times. Patients who experienced more than 5% decrease in BMI compared with baseline had 5.165 (95% CI: 1.735 to 15.370, P = 0.003) times the progression risk of patients whose BMI changed within ±5% from baseline. Conclusions:The advantage of obese clear cell carcinoma patients over normal-weight patients in tumor progression-free survival may be influenced by ASMI, pre-onset involuntary weight loss and lipid levels. Therefore, patient weight management should not merely focus on absolute BMI but tailor to individual characteristics, including cancer stage, body composition and metabolic status.