We evaluated, in burn patients, the metabolic and hormonal effects of early nutritional supplementation after a severe stress event represented by the deep surgical excision of the burn wounds and autograft coverage. The surgical procedure induced a 50% increase from baseline value of the resting metabolic rate. Immediate nutritional supplementation avoids the adaptive stress-related increments of urinary catecholamine excretion and glucagon secretion while insulin secretion is maintained. The urinary cortisol excretion, significantly increased after surgery in study and control groups, was unaffected by the nutritional intervention. The favorable insulin/glucagon ratio and the control of catecholamine response in early nutritionally supplemented patients are associated with the maintenance of a positive N balance in the days after surgery.