Does milk contain protein? Of course it does. The amount of protein in milk can vary from 8g to 24g per cup. Reduced fat, low fat and non fat milk contain approximately 8g of protein, evaporated (condensed) milk contains 24g of milk per cup. Generally the protein from milk is casein protein, and as such is absorbed into the body slowly over a long period of time, usually a few hours. This is why whey protein is taken with milk, since the whey protein provides the body with the immediate boost and the milk supplies its protein slowly.