A continuous measurement of the energetic consumption and a nutritional evaluation were performed over 24 hours in two comparable groups of children under cyclic or continuous total parenteral nutrition (TPN). Over the 24 hours, energetic consumptions and nitrogenous retentions were equal in both groups. In cases submitted to continuous TPN, a similar utilization of nutriments was observed during the day and night periods, with global predominance of carbohydrate oxidation and of lipogenesis. In cases submitted to cyclic TPN, night and day utilization of nutriments was significantly different, with important utilization of glycogen and lipid stocks during the day. Thus, cyclic TPN allows a more important mobilization of the energetic stocks and physical activity during the day than continuous TPN and might change the quality of the weight gain and avoid an unnecessary storage of lipid deposits.