Both retrospective and prospective analyses of the effects of various fasting regimens were carried out on the achievement of calculated caloric needs of patients with severe burns. The records of patients who received enteral feedings while undergoing burn debridements were divided into three groups and retrospectively analyzed to determine the effect that duration of fasting had an achievement of caloric needs and on the risks of aspiration. Patients in two other groups were prospectively studied to determine the safety and efficacy of stopping continuous enteral feedings 1 and 4 hours before surgery, respectively. Techniques of airway management and anesthetic induction were left to the discretion of the attending anesthesiologist. In the retrospective analysis, patients in group I, who fasted for 2 hours achieved 28% of their calculated 24-hour caloric goals compared with 11% in those who fasted for 2 to 8 hours (group II) and 6% in those who fasted for more than 8 hours (group III) before surgery (p less than 0.001). In the prospective portion of the study, patients who fasted for 1 hour before anesthesia was induced achieved 30% of their caloric needs, whereas those who fasted for 4 hours achieved 15% of their target nutritional needs (p = 0.0001). No patient had evidence of pulmonary aspiration. We conclude that controlled enteral feedings and shortened preoperative fasting periods can safely enhance nutritional support in patients with burns.