The rate of energy expenditure was repeatedly measured by indirect calorimetry both in the basal state (BMR) and in the resting fed state (RMR) in 8 middle-aged male patients operated for oropharyngeal cancer. In the postsurgical phase, two sequential energy levels were administered by nasogastric tube: (1) a ‘maintenance’ level (days 3–5) at 1.4 × measured presurgery BMR; (2) a ‘supramaintenance’ level (days 6–9) at 1.7 X measured BMR on day 6. Before surgery the patients had a BMR averaging (23.7 ± 1.0 kcal/kg·day). After surgery BMR increased to 27.6 ± 2.7 kcal/kg·day (day 6), then it decreased to 24.4 ± 1.4 kcal/kg·day (day 10). The difference between RMR and BMR yielded a nutrient-induced thermogenesis averaging 5 ± 1 and 8.5 ± 2% (p < 0.05) on levels 1 and 2, respectively. It is concluded that an energy level corresponding to 1.4 × presurgery BMR is sufficient to maintain energy and substrate equilibrium in nondepleted patients, whereas 1.7 × BMR induces positive protein and fat balances concomitant to a decrease efficiency