Dietary carbohydrates are the most potent stimuli of insulin secretion. However, the addition of dietary protein in a carbohydrate-rich meal has been shown to further stimulate insulin release.The insulinotropic effect of dietary protein is thought to be attributed to the branched-chain amino acid (BCAA) content of the protein-rich meal. Interestingly, there is a hierarchy of effects induced by protein from different sources. For example, milk protein has been shown to be superior to fish or plant protein in stimulating insulin secretion following a meal.Even within milk protein, whey protein stimulated insulin secretion more than casein protein. One of the factors that distinguish whey from casein proteins was the digestibility or the digestion rate of these proteins. Protein that is digested faster appear to increase blood amino acid levels faster, and increase insulin release faster.This implies that plant proteins that have lower digestibility rate relative to animal proteins may have lower insulinotropic effects, and the effective dose required to achieve optimal insulin secretion may be different from animal protein and warrants further investigation. In addition, the amino acid profile (in addition to lower digestibility) of plant proteins may differ from animal protein, especially the BCAA content that is associated with the stimulation of insulin secretion.