The aim of this study was to assess the variation in levels of glucose and selected peptide hormones (insulin, leptin and ghrelin) in blood serum of young adults, depending on their nutritional status. Investigations were conducted with the participation of 18 persons, which were divided into three groups characterised by different nutritional status – BMI: 25 kg/m². Blood samples were collected from each examined person before they have eaten and next blood serum levels were determined for glucose, insulin, leptin, active and total ghrelin. Significant (p<0.05) inter-group differences were shown in leptin concentration, with the highest values of this parameter shown in the group of overweight persons (31.68±23.29 ng/cm³), while the lowest for individuals with BMI<20 kg/m² (5.81±4.57 ng/cm³). Statistically significant correlations were found between BMI and leptin level (r=0.56, p<0.05), the share of fat mass and levels of insulin (r=0.52, p<0.05) and leptin (r=0.81, p<0.001), as well as the mean skinfolds thickness and the concentration of insulin (r=0.47, p<0.05) and leptin (r=0.63, p<0.01).