Body Weight Reduction and Metabolic/Biochemical Parameters in Overweight or Obesity

This was a single-center prospective observational cohort study conducted at the Medical University of Silesia in Katowice, Poland, and in a metabolic outpatient clinic in Miasteczko Śląskie, Poland. The study was designed to evaluate the effect of body weight reduction on selected metabolic, biochemical, oxidative-stress, inflammatory, and body-composition parameters in individuals with overweight or obesity. The study was conducted in the context of routine metabolic outpatient care. Participants with overweight or obesity received standard lifestyle-based body weight reduction management, including individualized dietary recommendations, physical-activity guidance, health education, and regular follow-up visits. The investigators did not assign participants to an investigational medicinal product, medical device, dietary supplement, surgical procedure, pharmacological intervention, or experimental therapy. The study prospectively observed participants receiving routine lifestyle-based weight reduction management and assessed changes in clinical and laboratory parameters before and after body weight reduction. The approved study protocol planned the inclusion of individuals with overweight or obesity and a normal-weight comparison group. Participants with BMI \> 25 kg/m² were evaluated in relation to body weight reduction, while individuals with normal body weight served as a comparison group for selected baseline analyses. Patients with overweight or obesity were assessed by medical examination, dietary and clinical questionnaires, anthropometric measurements, body-composition analysis, and fasting blood sampling. Body-composition analysis included assessment of body weight, fat mass, fat-free mass, skeletal muscle mass, total body water, visceral fat, and related parameters. Blood samples were collected for biochemical analyses, including markers of glucose metabolism, lipid metabolism, oxidative stress, antioxidant status, inflammatory markers, adipokines, cytokines, chemokines, growth factors, and selected cardiovascular-risk parameters. Participants with overweight or obesity were followed during standard body weight reduction management until clinically relevant weight reduction or achievement of optimal body weight. According to the original study documentation, assessments were planned before the start of weight reduction, after approximately 10% body weight reduction, and after approximately 20% body weight reduction or achievement of target body weight. Follow-up visits included body weight measurements, waist and hip circumference measurements, dietary counselling, education regarding caloric intake, and motivation to continue lifestyle modification. The primary objective of the study was to assess whether body weight reduction in individuals with overweight or obesity is associated with changes in selected metabolic and biochemical parameters. Secondary objectives included evaluation of oxidative-stress and antioxidant-status parameters, glucose and lipid metabolism, inflammatory markers, adipokines, cytokines, and body-composition changes. The study also aimed to assess relationships between biochemical parameters and body-composition indices before and after body weight reduction. The study was approved by the Bioethics Committee of the Medical University of Silesia in Katowice, Poland. All participants received information about the study and provided written informed consent before participation. This ClinicalTrials.gov record is submitted retrospectively to meet journal publication requirements and to provide transparent public information about the completed study.