Animal (food) products are rich sources of protein. Meat, milk and milk products, egg, poultry, and fish, contain balanced level of amino acids. Protein can also be obtained from plant (vegetable) food items such as legumes (soybean and soybean products, peas, beans etc.), and nuts.
Some differences between animal protein and plant (vegetable) protein are: (1) animal protein is generally associated with high fat content and because of that, when consumed in large amounts, it is attributed to high risks of diseases, including high blood pressure and heart diseases; (2) animal protein has a balanced combination of all the amino acids, hence it is called complete protein. To the contrary, plant (vegetable) protein is incomplete, soybean protein is an exception to this. However, even soy protein is deficient in methionine (an essential amino acid). With vegeterian diet, to achieve a balanced amino acids intake, a variety of plant protein sources need to be complemented with each other in the diet. Incomplete protein is deficient in one or more of the essential amino acids. Vegetable protein sources are also good sources of dietary fiber and generally low in low fat content, particularly saturated fats.