Animal vs. Plant Protein — What’s the Difference? About 20% of the human body is made up of protein . Because your body doesn’t store protein, it’s important to get enough from your diet each day. You can get protein from many food sources, including plants and animals. Some people claim that the source of the protein, whether animal or plant, shouldn’t matter. Others suggest that plant protein is superior to animal protein. This article compares animal and plant proteins. The Amino Acid Profile Varies Between Plant and Animal Proteins When eaten, protein is broken down into amino acids. Proteins and amino acids are used for almost every metabolic process in the body. However, different proteins can vary greatly in the types of amino acids they contain. While animal proteins tend to contain a good balance of all the amino acids that we need, some plant proteins are low in certain amino acids. For example, some key plant proteins are often low in methionine, tryptophan, lycine and is