The study was aimed at determining differences in the content of carbohydrates as well as fat and its constituents in diets of 10-15-year-old children characterised by different nutritional status and originating from small towns of the central-eastern Poland. The study demonstrated that the diet of overweight and obese children (BMI>90 ptc) compared to that of the thin children (BMI<10 ptc) was characterised by a higher mean content of fats (32.5 cal% vs. 30.5 cal%), a lower concentration of carbohydrates (54.8 cal% vs. 56.8 cal%), a lower mean ratio of polyunsaturated to saturated fatty acids (0.36 vs. 0.45), and a higher mean content of cholesterol (343 mg/24 h vs. 298 mg/24 h). The linolic acid:α-linolenic acid ratio as well as the vitamin E:linolic acid ratio were alike in all groups examined. From the point of view of the prevention of ischaemic heart disease, it seems that the diet of children with overweight and obesity had more features facilitating atherogenesis than the diet of thin children. The results obtained may also indicate relationships between nutritional status (estimated on the basis of BMI and body adiposity) and diet composition, i.e. indirectly, eating patterns of the children analysed.