Chapter 7 – Nutrition


Protein is another major macronutrient that, like carbohydrates, consists of small repeating units. But instead of sugars, proteins are made up of amino acids.

Proteins can be classified as either complete or incomplete. Complete proteins provide adequate amounts of all nine essential amino acids. Animal proteins, such as meat, fish, milk, and eggs, are good examples of complete proteins. Incomplete proteins do not contain adequate amounts of one or more of the essential amino acids. For example, if a protein does not provide enough of the essential amino acid leucine it would be considered incomplete. Leucine would be referred to as the limiting amino acid because there is not enough of it for the protein to be complete. Most plant foods are incomplete proteins, with a few exceptions, such as soy. The following link discusses limiting amino acids and protein complementation:

Self Magazine’s Nutrition Data website is a useful resource for determining protein quality and identifying complementary proteins. To use the site, go to, type the name of the food you want information on in the search bar and hit Enter. When you have selected your food from the list of possibilities, you will be given information about this food. Included in this information is the Protein Quality section. This will give you an amino acid score and a figure that illustrates which amino acid(s) is limiting. If your food is an incomplete protein, you can click “Find foods with a complementary profile.” This will take you to a list of dietary choices that will provide complementary proteins for your food.


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Health and Fitness for Life Copyright © 2019 by Dawn Markell and Diane Peterson is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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