Proteins are imperative for muscles
Like other nutrients protein plays imperative functions in muscles over all health and growth. It helps in the production of enzymes and hormones. It acts as carrier and transporter of the other nutrients. It is also indispensable for contracting and rejuvenation of muscles. When you lift weights and dumbbells then you tear your muscles fibers.
These torn muscle fibers are strengthened and repair by the protein. If your body will lack protein then muscles will unable to repair themselves proper and quickly. Body builders are required more protein to build their muscles as compare to the normal human beings.
Generally factors like fitness objectives, gender, weight lifting and ways of life can affect the protein needs in your life. For a body builder a definite quantity of protein per body weight (pounds) is necessary. Peanut, beef, chicken, grains, eggs etc are the good source of protein and other important nutrients.