Proteins are indispensable for growth and maintenance of every kind of cell in our body. Body development, replenishment of lost blood, healing of wounds and scars, replacement of dead cells, and hair and nail growth need proteins. Proteins in the form of enzymes, hormones and antibodies promote healthy metabolic and physiological processes, and boost our nervous and immunity systems. In situations when fat and carbohydrate food sources are not providing adequate calories, proteins are degraded to generate the calories our body needs.