Three preloads: high in simple carbohydrates (fruit juice), high in complex carbohydrates (banana) and high in protein (chicken meat), were tested in two groups of preschool children (56), aged 2 to 4 years from both genders. One group had a normal weight for height and the other high weight for height. The preload were given thirty minutes before lunch. The lunches consisted in a legume dish, apple and a milk dessert. Children were stimulated but not forced to eat and the amount of foods consumed was determined by differential weighing. The results showed that overweight children had a lower consumption at lunch that normal children when the high carbohydrate preloads were tested. High simple carbohydrate preload, 338,2 +/- 87.0 vs 350,9 +/- 75.9, high complex carbohydrate preload, 336.2 +/- 109.6 vs 375.4 +/- 89.4. High protein preload had not effect on the lunch consumption in the two groups of children studied. When an analysis by age of children were made, dividing the normal and overweight children in two groups, 24 to 36 months and 36 to 48 months, it was demonstrated that differences in lunch consumption between the normal and overweight children was derived essentailly from the results obtained in children of 24 to 36 months, high simple carbohydrate preload 282.3 +/- 88.9 g vs. 318.5 +/- 80.0 g and in the high complex carbohydrate preload, 262.6 +/- 98.9 g vs 364.5 +/- 116.3 g. When energy intake derived from food consumption was analyzed, the same tendency described for food consumption was demonstrated. The results presented show a different response of overweight children to the high carbohydrate preloads consumed before lunch, specially in children aged 24 to 36 months. This findings are important since they give an experimental information that can be utilized to find metabolic answers in relation to the onset of obesity in the childhood and to establish dietary recommendations in order to alleviate the risk of obesity in children.