After total removal of the stomach, proteins can be digested and absorbed by the protease secreted by the pancreas, but their digestion and absorption rate will be significantly affected compared to the preoperative period. The stomach is the digestive organ of the organism, and its main function is to temporarily hold food and perform physical digestion, grinding food into smaller shapes, as well as chemical digestion, degrading large molecules into smaller ones. The gastric juice contains proteases and gastric acid, which can initially digest proteins. After the stomach is completely removed, the body’s digestive function will be affected to some extent. However, the pancreas can secrete a large amount of trypsin, and after eating food, trypsin can digest the proteins in the food and break them down into small absorbable molecules, which are then absorbed through the mucosa of the small intestine. In summary, after total gastrectomy, the ability to digest and absorb proteins will be reduced, but not completely undigested and unabsorbed, because pancreatic protease can play a role in digestion.