Food Scoring Guide: Complete Protein

When you hear something over and over from the time you were a young child, it is easy to accept it as true. So it should not come as a surprise that the myth that we need to consume animal products to get adequate protein is still alive and well in America. The myth that plant proteins are “incomplete” and need to be “completed” for adequate protein is still alive, too.

Amino acids are the building blocks that make proteins. All vegetables and grains contain all eight of the essential amino acids (as well as the twelve other non-essential). While some vegetables have higher or lower proportion of certain amino acids than others, when eaten in amounts to satisfy your caloric needs, a sufficient amount of all essential amino acids is provided. Today’s nutritional science has deemphasized the importance of protein because we now know that it is easy to get enough, and that too much is not good.

Scientific studies on human protein requirements demonstrate that adults require 20-35 grams of protein per day.1 Today, the average American consumes 100-120 grams of protein per day, mostly in the form of animal products. This high level of animal product consumption has been linked to not just heart disease and strokes, but to higher rates of cancer, as well.2 We simply don’t need all this protein. Even people who eat a total vegetarian (vegan) diet, which contains no animal products, have been found to consume 60-80 grams of protein per day, well above the minimum requirement.3
1. Rose W. “The amino acid requirements of adult man.” Nutritional Abstracts and Reviews 1957;27:631.

2. Kelemen LE; Kushi LH; Jacobs DR; Cerhan JR. “Associations of dietary protein with disease and mortality in a prospective study of postmenopausal women.” Am J Epidemiol 2005;161(3):239-49.

Kant AK; Schatzkin A; Graubard BI; Schairer C. “A prospective study of diet quality and mortality in women.” JAMA 2000;283(16):2109-15.

Meydani M. “Nutrition interventions in aging and age-associated disease.” Ann NY Acad Sci 2001;923:226-35.

3. Hardage M. “Nutritional studies of vegetarians.” Journal of the American Dietetic Association 1966;48:25.
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Barbara Womer - January 31, 2008 10:07 PM

As a volunteer I am leading a class on SAD nutrition in a large Virginia prison for women for those inmates about to be released. The representative from Virginia Extension Service to whom I am responsible believes that plant protein needs to be combined to be complete. I did raise my objections at that point but she wants to know what study disproves that concept. Whew! teaching what you don't believe in is tough but I hope to at least get these women to stop eating potato chips, and maybe a little more.

Michael - February 1, 2008 9:01 AM

Here is a good place to start. I would stick to mainstream sources like the AHA, ADA, NIH, etc.

Jack Alpan, DDS, NMD - October 28, 2009 6:31 PM

I saw your video on the Real Food Channel regarding Nutrient Density of foods. Do you have a more complete list of Nutrient Density that includes legumes, and all the healthy foods one could eat?

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