A total of 110 barrows fed varying levels of energy and amino acids in 8 treatments, were tested. The weight gains per fattening day and energy expenditure were found to be mainly determined by energy intake. Up to a liveweight of 100 kg both low and high levels of amino acid supply produced the same fattening performance results as amino acid supply to standard. In the 100-120 kg liveweight range, the animals fed higher levels of protein proved slightly superior. As to energy expenditure, animals subjected to restricted feeding up to 70 kg liveweight and fed full rations later, consumed 2.22 kEFs (2.22 kilo energetic feed equivalents/swine) per kg gain and proved significantly superior to those animals that were very intensively fed at the beginning and put to restricted feeding beyond 70 kg liveweight (2.53 kEFs per kg gain) as well as to those receiving high levels of energy all the time (2.39 kEFs/kg gain). In the latter case, 23 g of lysine were required per kg gain.