Background. ThePPARG2Pro12Ala (rs1801282) andIL6-174G >C (rs1800795) have important function in body weight regulation and a potential role in obesity risk. We aimed to investigate the association betweenPPARG2Pro12Ala andIL6-174G >C variants and the genotypes interaction with body composition, metabolic markers, food consumption, and physical activity in severely obese patients.Methods. 150 severely obese patients (body mass index (BMI) ≥ 35 kg/m²) from Central Brazil were recruited. Body composition, metabolic parameters, physical activity, and dietary intake were measured. The genotype was determined by the qPCR TaqMan Assays System. Multiple linear regression and multiple logistic regression models were fitted adjusting for confounders.Results. Ala carriers of the Pro12Ala polymorphism had higher adiposity measures (BMI:p=0.031, and fat mass:p=0.049) and systolic blood pressure (p=0.026) compared to Pro homozygotes. We found no important associations between the -174G >C polymorphism and obesity phenotypes. When genotypes were combined, individuals with genotypes ProAla + AlaAla and GC + CC presented higher BMI (p=0.029) and higher polyunsaturated fatty acids (PUFAs) consumption (p=0.045) compared to the ones with genotypes ProPro and GG, and individuals carriers of thePPARG2Ala allele only (genotype ProAla + AlaAla and GG) had higher fat mass and systolic and diastolic blood pressure compared to the ones with genotypes ProPro and GG.Conclusions. Severely obese individuals carrying the Ala allele of thePPARG2Pro12Ala polymorphism had higher measures of adiposity and blood pressure, while no important associations were found for theIL6-174G >C polymorphism.