Definition of Protein
Protein: One of the three nutrients used as energy sources (calories) by the body. Proteins are essential components of the muscle, skin, and bones. Proteins and carbohydrates each provide 4 calories of energy per gram, whereas fats provide 9 calories per gram.
Last Editorial Review: 3/19/2012
Back to MedTerms online medical dictionary A-Z List
Need help identifying pills and medications?
Get the latest health and medical information delivered direct to your inbox FREE!