Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs. Proteins are made up of hundreds or thousands of smaller units called amino acids, which are attached to one another in long chains.Some examples of protein foods are meats such as pork, chicken and beef. Fish is also a high protein food along with; eggs and dairy, dried beans (including soy) and nuts and seeds (especially peanuts).