In this study, computerized indirect calorimetric measurements were made using a medical graphics critical care monitor (CCM) desktop analysis system in the observation of metabolic state of 20 patients complicated with external gastrointestinal fistula. While these malnourished patients were provided with 1.5 x REE in total energy intake, the malnutrition state could be reversed. But with 1.75 or 2.0 x REE or up total energy intake, the general nutritional state could not be improved faster, the O2 consumption and CO2 production and energy expenditure increased, while the net glucose oxidation increased and net lipid oxidation decreased or net lipogenesis occurred simultaneously. We believed that superfluous energy intake is harmful to critically ill patients and may lead to cell injury and dysfunction.