After a 5-day preoperative preparing period, 24 metabolically healthy patients, who had to undergo gastric resection, were fed postoperatively by hypocaloric total parenteral nutrition for a 5-day period. Group I, n = 13; received 0.11 g Xylitol/kg BW . h; Group II, n = 11, received 0.11 g Glucose/kg BW . h. Both groups received 1.71 g L-crystalline amino acids/kg BW . day. During the whole postoperative period, group II had significantly higher serum glucose and insulin levels. Due to the high postoperative insulin concentration in group II, free fatty acids, acetoacetate, beta-hydroxybutyrate and branched chained amino acids were significantly lower. The augmented release of muscle amino acids and the covering of a part of the energy expenditure by increased fatty acid oxidation in group I led to a higher postoperative synthesis rate of visceral proteins. From postoperative day 3 on transferrin and from postoperative day 6 on albumin and total protein were significantly higher in group I. This study could demonstrate that due to its special role in the intermediary metabolism during the postoperative period xylitol leads to a significantly higher regeneration rate of visceral proteins compared to glucose during total parenteral nutrition.