Three trials were conducted with 60 kg growing pigs. In trial 1, four diets ranging in CP level between 18.9 and 12.3 per cent were used, whereas in trials 2 and 3, two diets with 17.4 and 13.9 per cent CP were used. In trials 1 and 2, the feed was given as 4 meals per day whereas in trial 3, 2 frequencies (2 and 7 meals per day) were compared. The results show that decreasing the CP content allows a reduction of nitrogen excretion by 40 (trials 2 and 3) or 60 per cent (trial 1), without affecting the nitrogen retention. This reduction in nitrogen excretion was accompanied by both a reduction in urinary energy losses and of heat production equivalent to 3.5 and 7 kJ per gram decrease in protein intake, respectively. Meal frequency (trial 3) had no effect on nitrogen and energy utilization.