In men with normal body weight, we have noted an increase in postprandial leptin levels only after meals that contained carbohydrates (the difference 240 min after meal intake was on the margin of significance), and this observation seems to be consistent with the results of Monteleone et al. [41] and Romon et al. [42], who showed that in people with normal body weight and BMI ≤ 27 kg/m2, leptin concentrations after an HC-meal were higher than after consumption of the HF-meals, while leptin levels decreased. This evidence concerns the gene LEP and hydrops fetalis.