The PPARgamma Pro12Ala polymorphism has been associated in several studies with a decreased risk of obesity, type 2 diabetes and insulin resistance. Weak hints are available about the influence of PPARgamma Pro12Ala on postprandial metabolism. In 708 men, aged 45 to 65 years the PPARgamma2 Pro12Ala genotypes were determined and postprandial TAG, insulin, glucose and NEFA after a standardized mixed fat meal and insulin and glucose after a glucose load (oral glucose tolerance test; OGTT) were assessed. Using the total sample, we did not find a significant impact of the genotype on the postprandial metabolism. In the subgroup with BMI <30 kg/m2, fasting and postprandial TAG and insulin levels as well as homeostasis model assessment of insulin resistance (HOMA) were significantly lower in the Ala12Ala group than in the Pro12Pro group after the mixed meal. In contrast, the groups did not differ in insulin levels and HOMA after the OGTT. To investigate if differences between a fat-containing meal and OGTT are caused by adiponectin, we examined a BMI- and age-matched subgroup. No differences were found between the genotypic groups. The effects of the PPARgamma2 polymorphism on insulin sensitivity are mediated by affluent dietary fat. We did not find evidence that adiponectin as a fatty-acid-dependent adipocyte factor is a causative factor for this phenomenon.