Meats tend to be high in protein. Specifically, chicken, turkey, tuna, salmon and beef are all good sources of protein. Some plant foods are also high in protein; these include beans, quinoa and tofu.
Chicken is an excellent source of protein, with a 4-ounce serving containing 35 grams of the macronutrient. Turkey contains 34 grams of protein per 4-ounce serving, and tuna contains 33 grams of protein per 4 ounces. A 4-ounce serving of salmon contains 27 grams of protein per serving, and a 4-ounce serving of beef contains 26 grams.
Vegetarians and vegans prefer to get their protein from plant foods rather than from animal products. Beans are one of the most protein-dense plant foods. One cup of canned kidney beans contains 13.4 grams of protein. Quinoa, which contains 18 grams of protein per cup, and tofu, which contains 10 grams of protein per half-cup, are also good sources of protein for vegetarians.
Protein is a macronutrient that the body uses for several physiological functions, including the production of muscle and connective tissue, the release of enzymes and the formation of antibodies. Protein deficiency is rarely seen in western society, but is a problem in impoverished nations where people do not have access to enough food. Protein deficiency leads to slow growth and muscle wasting.