Sources of protein

Complete proteins

There are some foods that contain all of the 8 essential amino acids required to form the new proteins together with the non-essential amino acids. These foods are called "complete" proteins and tend to come from animal sources of protein such as meat, dairy products, eggs, fish, shellfish and poultry. 

The proteins that are termed "incomplete" proteins are usually lacking in one or more of the essential amino acids. They are generally found in vegetable products like fruits, vegetables, pulses, grains and nuts. 

However, by combining two or more of the "incomplete" proteins, a complete supply of essential amino acids is available. For example, baked beans on toast or rice and beans will form a complete protein and give the body all the essential amino acids.

Incomplete proteins

Below is a chart listing some incomplete proteins. To get all of the essential amino acids, simply choose foods from two or more of the columns.

While just about every vegetarian food contains some protein, the soybean deserves special mention, for it contains all the essential amino acids and surpasses all other food plants in the amount of protein that it can deliver to the human system. In this regard, it is nearly equal to meat. The human body is able to digest 92 percent of the protein found in meat and 91 percent of that found in soybeans.

Sources of protein

Other rich sources of non-animal protein include legumes, nuts, seeds, yeast, and freshwater algae. Although food yeasts ("nutritional yeast" and "brewer’s yeast") do not lend themselves to forming the center of one's diet, they are extremely nutritious additions to most menus (in soups, gravies, breads, casseroles, and dips). Most yeasts get about 50 percent of their calories from protein.

Other good sources of protein include:

• Chicken (100g - 27 grams of protein)
• Turkey (100g - 25 grams of protein)
• Beef (100g - 22 grams of protein)
• Fish (100g - 21 grams of protein)
• Lamb Chops (100g - 21 grams of protein)
• Duck (100g - 20 grams of protein)
• Cottage Cheese (100g - 14 grams of protein)

Read more from our protein series:

• What is protein?
• Sources of protein
• How much protein?
• Too much protein or not enough protein?
• Protein and training