Background/Objectives: Total weight loss after laparoscopic sleeve gastrectomy (LSG) does not fully capture changes in body composition, particularly the loss of lean mass. We examined sex-specific changes in regional and whole-body composition before and one year after LSG. Methods: This retrospective single-center study included 121 adult patients (84 female, 37 male) who underwent LSG at Istanbul Aydin University Faculty of Medicine between May 2017 and February 2025. Multi-frequency segmental bioelectrical impedance analysis was performed pre-operatively and at one year post-operatively. Three ALM normalization indices (ALM/weight × 100, ALM/BMI, ALM/height²) were compared before and after surgery. Associations between pre-operative fat mass (FM) and ALM were examined using sex-stratified linear regression with and without adjustment for height, age, and sex via ordinary least squares residualization. Results: Pre- and post-operative values were compared. We found that BMI, fat-free mass (FFM), and FM decreased significantly in both sexes (all p < 0.001), with comparable total weight loss between females and males (p > 0.05). Males lost more absolute FFM and showed greater proportional lean mass loss in the limbs, while females showed greater proportional loss in the trunk. After adjusting for height, age, and sex, pre-operative FM was positively associated with ALM both pre-post-operatively (both p < 0.001). Patients with greater pre-operative FM lost more ALM over the surgical year. Conclusions: Body composition changes following laparoscopic sleeve gastrectomy in this cohort of 121 patients were metric-dependent. Patients with lower pre-operative adiposity may present with lower post-operative ALM one year after LSG.

Background: The inflammatory potential of diet and the accumulation of advanced glycation end products (AGEs) are key factors contributing to cellular dysfunction and aging-related processes. The dietary inflammatory index (DII) is a validated tool used to quantify the inflammatory potential of dietary intake. This study aimed to investigate the association between serum carboxymethyl lysine (CML), a major biomarker of AGE burden, and DII scores. Methods: A total of 149 volunteers were included. DII scores were calculated based on three-day dietary records. Anthropometric measurements were obtained using the Tanita MC 980 body composition analyzer. Serum CML levels were measured using the enzyme-linked immunosorbent assay. Results: A statistically significant but weak inverse correlation was observed between serum CML levels and DII scores ( r = −0.175; P = 0.033). Serum CML concentrations did not differ significantly according to sex, body mass index, or presence of chronic disease ( P > 0.05 for all). Conclusions: These findings demonstrate an inverse association between dietary inflammatory potential and circulating CML levels, highlighting the potential role of diet-related inflammation in AGE formation and aging-associated metabolic processes. Although the observed correlation was modest, the results emphasize the complex biological interplay between diet, inflammation, and AGE accumulation. Given the relatively young study population and limited sample size, the findings should be interpreted cautiously. Future studies including larger and more diverse cohorts, as well as comprehensive assessments of dietary components and antioxidant capacity, are warranted to inform dietary strategies for the prevention of AGE-related diseases.