Simply put, a person needs to balance how much protein they eat with how much the body uses and loses. Protein Use Our bodies respond to different proteins in different ways, depending on several factors including how healthy we are and what protein foods we eat. Protein will be used most efficiently if it is accompanied by carbohydrate, fat, and a variety of vitamins and minerals. A person in good health generally uses protein efficiently. However, malnutrition or infection can severely affect protein digestion by reducing the secretion of enzymes, decreasing absorption, causing nutrient losses from diarrhea, and using protein to meet other bodily needs.
Infections also cause an increased demand for production of antibodies made up of protein.
Malnutrition or infection may significantly increase the body's needs for protein while simultaneously making it harder to meet them. In Western societies, where food is abundant, most people generally meet their protein needs with ease. When food energy intake is limited, the situation is different. In cases of widespread malnutrition, or when the selection of available food is severely limited it may be difficult to meet protein needs. This is especially true in diseases that cause protein losses.