Objective: To study the effect of the rs1801282 PPARG polymorphism on changes in the body composition of patients with early carbohydrate metabolism disorders in groups with different variants of treatment.Materials and Methods: The study involved 64 patients (8 men and 56 women) with early carbohydrate metabolism disorders. At baseline, all patients underwent genotyping for the rs1801282 PPARG polymorphism and body composition determination with bioelectrical impedance analysis (BIA). Then, the patients were divided into two groups depending on the type of therapy. The patients from Group 1 (40 subjects, mean age 45.2±15.4 years) kept a generally accepted diet with the exclusion of simple carbohydrates and limitation of complex carbohydrates and fats. The patients from Group 2 (24 subjects, mean age 51.2±14.5 years) took metformin in addition to the diet therapy. The effects of different types of treatment on body composition changes were assessed with follow-up BIA 3 months after the start of treatment.Results: Carriers of the mutant G allele of rs1801282 PPARG in the metformin and diet therapy group showed a significant increase in the content of body cell mass (1.28±0.51% vs 0.36±0.37%; P = 0.021) compared with CC homozygotes in the absence of differences in body weight changes (P > 0.05).Conclusions: The presence of the mutant allele G of rs1801282 PPARG promotes the increase in body cell mass in case of adding metformin to the diet therapy in patients with early carbohydrate metabolism disorders.