Investigate whether polymorphism in the promoter region encoding leptin and leptin receptor gene, in normal weight individuals, affects hormonal and appetite responses to peanuts.

Appetite, anthropometric indices, body composition, physical activity, dietary intake and leptin, ghrelin and insulin levels were monitored. Polymorphism analyses were also carried out.

None of the treatments led to statistical differences in the analyzed hormones. No polymorphism was found for leptin receptor gene, while for leptin gene, 50% of the volunteers presented one polymorphic allele and 13% presented both polymorphic alleles. These last ones presented lower body fat mass, leptin and ghrelin plasma concentrations, and fullness rates. They also presented higher hunger, desire to eat, and desire to eat sweet and salty foods.

Peanut did not affect appetite and presented no different hormonal responses, compared to other foods studied. Polymorphic allele carriers in both alleles presented higher probability to develop obesity. However, the magnitude of this probability could not be measured.