Maximum protein levels are reached by eating a range of different foods which contain protein. It is important for vegetarians to get their protein from other non meat protein products e.g. soya, beans, and lentils.

Function.
Provides us with a little energy but main function is growth and repair of the body.

Sources.
Meat, fish, eggs, cheese and other dairy products, nuts, beans, lentils, wheat, corn, soya, rice.