ObjectiveTo observe the changes of body composition in patients with obesity after sleeve gastrectomy (SG) and know the factors affecting the effective weight loss. MethodsThe obese patients who received SG treatment at the Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University from October 2019 to October 2022 were included according to the inclusion and exclusion criteria. The anthropometric parameters, lipid metabolism indexes, and body composition data were collected before surgery (1 d) and at 1-, 3-, 6-, and 12-month after surgery. The risk factors affecting the effective weight loss were analyzed. ResultsA total of 170 patients were included in the study. ① The anthropometric parameters such as body weight, body mass index, waist circumference, hip circumference, and waist-to-hip ratio at different time points after surgery as compared with the baseline (1 day before surgery) values were decreased (P<0.05) and showed continuous downward trends after surgery (P<0.05), meanwhile the percentage total weight loss and percentage excess weight loss (%EWL) indicators showed continuous upward trends (P<0.05). ② The lipid metabolic indexes such as triglyceride, total cholesterol, and uric acid, except for the total cholesterol indexes at the 6th and 12th month had no statistical differences as compared with the baseline value (P>0.05) and the uric acid was increased at the 1st month after surgery (P<0.05), the other indexes at different time points after surgery showed continuous downward trends as compared with the baseline values (P<0.05). ③ All the body composition parameters except percentage fat-free mass of the left and right lower limbs (P>0.05) at different time points after surgery as compared with the baseline values were decreased (P<0.05), and some body composition indicators, such as fat mass, percentage fat mass, visceral fat area, and obesity degree continued to decrease within 1 year after surgery (P<0.05). ④ There were 93 patients with reaching the standard of effective weight loss (%EWL was 50% or more). The multivariate logistic regression analysis showed that the lower fat mass of right lower limb, the higher probability of effective weight loss [OR (95%CI)=0.452 (0.290, 0.703), P<0.001]. The area under the receiver operating characteristic curve of the fat mass of the right lower limb was 0.782 [95%CI=(0.672, 0.893), P<0.001], its sensitivity and specificity were 0.679 and 0.792, respectively, and the cut-off value was 7.35 kg. ConclusionsThe results of this study suggest that SG can markedly improve the anthropometric and lipid metabolism indicators of patients with obesity, and achieve effective weight loss in a short-time. The body composition from the whole body to limbs and trunk might be changed. The fat mass of the right lower limb is closely related to the short-term effective weight loss after surgery and it has a moderate ability to distinguish achieving effective weight loss.