Introduction and methods: A transition G to A at codon 54 of FABP2 results in an amino acid substitution (Ala 54 to Thr 54). This polymorphism was associated with high insulin resistance and different dietary response. The aim of our study was to investigate the influence of Thr54 polymorfism in the FABP2 gene on weight loss secondary to two hypoclaoric diets. A population of 76 obesity was analyzed in a prospective way. Before and after two months of hypocaloric diet, a nutritional evaluation was performed. Patients were randomly allocated to two groups: a) diet I (low fat) and b) diet II (low carbohydrate).

Results and conclusions: With diet Type I (low fat) and in wild group (Ala54/Ala54), BMI, weight, fat mass, waist circumference, waist to hip ratio, systolic and dyastolic blood pressures, total cholesterol, triglycerides and insulin levels decreased. In mutant group (Ala54/Thr54 and Thr54/Thr54), BMI, weight, waist circumference and fat mass decreased. In wild group with diet Type II (low carbohydrate), BMI, weight, fat mass, waist circumference, waist to hip ratio, systolic and dyastolic blood pressures glucose, total cholesterol, triglycerides and insulin levels decreased, too. In mutant group, BMI, weight, waist circumference and fat mass decreased. Only leptin levels have a significant decrease in wild group with both diets (diet I:30.7%:p<0.05) and (diet II:15.85%:p<0.05). In conclusion, weight loss is associated with changes in serum leptin concentration due to 2 months intervention with both diets. Two months of both hypocaloric diets improved in a different way nutritional parameters in wild patients than mutant patients.