The purpose of the study was to determine the efficacy of a low glycemic index diet on body weight loss in 30 overweight/obese children aged 7-12 years. Introduction of a low glycemic index diet as well as dietary counseling aimed at correcting the nutritional habits of the overweight/obese children brought about statistically significant body weight reduction (from 55.2±16.5 to 52.8±16.7; p=0.0001). Body mass index values declined from 23.6±3.3 to 21.8±3.3 in children aged 7-9 years and from 26.2±3.9 to 25.0±4.2 in children aged 10-12 years. Nutritional intervention also contributed to changes in the proportions of body composition, expressed by the significant decrease in average fat mass and total fat-free mass as well as to a statistically significant increase in total body water in all the subjects. Nutritional intervention caused a statistically significant decrease in the consumption of energy, fat, protein, and carbohydrates.