Leptin associations with body composition and lipid profile changes in women with overweight following dietary and exercise interventions.

Leptin plays a key role in appetite regulation and fat metabolism, and its relationship with body fat compartments and lipid markers under different diet strategies remains unclear. This study aimed to evaluate how changes in leptin levels are associated with body composition and lipid profiles in overweight individuals engaged in resistance training (RT), across time-restricted eating (TRE) and high-protein consumption intervention groups. A total of thirty-two overweight women, aged 18 to 30 years, were randomly divided into four intervention groups: time-restricted eating with high-protein intake (THP), time-restricted eating with regular-protein intake (TRP), high protein without time restriction (HP) and regular protein without time restriction (RP). All participants engaged in RT and followed a diet with a 25 % caloric deficit for 8 weeks. Participants in the high-protein groups consumed 1·6 g/kg/d of protein, whereas those in the standard-protein groups consumed 0·8 g/kg/d. Significant positive associations between changes in leptin and fat mass (FM) were observed in the THP (R2 = 0·69, P = 0·01) and TRP (R2 = 0·53, P = 0·03) groups. In contrast, no significant associations were identified between leptin and visceral adipose tissue, or subcutaneous adipose tissue in any group. Associations between leptin and lipid markers varied across intervention groups, with significant relationships observed for TG in the THP group (R2 = 0·59, P = 0·02) and for LDL-cholesterol (R2 = 0·51, P = 0·04) and HDL-cholesterol (R2 = 0·63, P = 0·01) in the HP group. These findings suggest that changes in leptin are more closely associated with changes in total FM than with regional adipose tissue depots. Associations between leptin and lipid markers were less consistent across intervention groups, indicating that the relationship between leptin and metabolic outcomes may be influenced by dietary context. Findings should be interpreted cautiously given the exploratory nature of the analyses and the relatively small sample size.