Protein is an important nutrient for growth and has many functions throughout the body, including being a major component of muscles. Protein is composed of substances called amino acids. There are 22 different amino acids but only 8 of these are considered essential as our bodies cannot make these and so these need to be provided in our diet.
Some people associate protein with animal products and believe that it would be difficult to obtain enough protein without eating meat and other animal products. However, this is incorrrect. Virtually all plant foods contain protein, including all the essential amino acids, and people on typical western omnivorous tend to have a protein intake that is two to three times more than is required. It was once thought that people who did not eat animal products needed to combine certain plant foods at the same meal in order to get the right combination of amino acids. However, this is unnecessary, as by eating a variety of foods from the plant food groups each day it is easy to get enough protein, and there is no need to make a special effort to meet protein needs. Human herbivores can get plenty of protein from plants just as herbivorous animals such as elephants, horses and cows do.
One reason the protein myth has persisted is that it was perpetuated in a very popular book, "Diet For A Small Planet" by Frances Moore Lappe, who was not trained in nutrition. But in the second edition of the book (in 1981) she retracted her original theory and wrote:
- "In 1971 I stressed protein complementarity because I assumed that the only way to get enough protein ... was to create a protein as usable by the body as animal protein. In combating the myth that meat is the only way to get high-quality protein, I reinforced another myth. I gave the impression that in order to get enough protein without meat, considerable care was needed in choosing foods. Actually, it is much easier than I thought.
- "With three important exceptions, there is little danger of protein deficiency in a plant food diet. The exceptions are diets very heavily dependent on  fruit or on  some tubers, such as sweet potatoes or cassava, or on  junk food (refined flours, sugars, and fat). Fortunately, relatively few people in the world try to survive on diets in which these foods are virtually the sole source of calories. In all other diets, if people are getting enough calories, they are virtually certain of getting enough protein."
The growing number of successful weight lifters and body builders on herbivorous diets provide examples that getting enough protein from plant foods is not a problem.