Weight Loss Composition and Metabolic Adaptation During Hypocaloric Dieting

Weight loss induced by hypocaloric dietary interventions is commonly accompanied by reductions in resting metabolic rate (RMR), a phenomenon often described as metabolic adaptation. The magnitude of this decline varies substantially between individuals and may depend not only on the amount of weight lost but also on the composition of weight loss, particularly the relative contributions of fat mass and fat-free mass. This prospective interventional study will investigate whether changes in body composition during a hypocaloric dietary intervention are associated with changes in RMR and metabolic adaptation. Approximately 150 adults with overweight or obesity will participate in a structured dietary program designed to induce moderate energy restriction. Body composition and resting metabolic rate will be assessed before and after the intervention to evaluate associations between fat mass loss, fat-free mass loss, and metabolic responses to weight reduction.

Inclusion Criteria * Adults aged 18 years and older. * Individuals living with overweight or obesity. * Willingness and ability to comply with dietary recommendations and study procedures. * Provision of written informed consent. Exclusion Criteria * Diagnosed metabolic or endocrine disorders known to affect energy expenditure. * Use of medications known to substantially affect metabolism or body composition. * Pregnancy or breastfeeding. * Any medical condition that, in the opinion of the investigators, precludes safe participation.