In a seriously ill patient, addition of amino acids in the diet results in a positive nitrogen balance. The mechanism for this is

Glucose, mannose, aminoacids (such as leucine, arginine, others) and β ketoacids such as acetoacetate (derived from fat catabolism) stimulate insulin secretin and have protein sparing effect. Insulin has anabolic effect on metabolism. It decreases protein catabolism and fat catabolism for energy production and increases aminoacid uptake and protein synthesis (positive nitrogen balance).