The China Study: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss and Long-Term Health

by T. Colin Campbell

Among animal foods, the proteins of milk and eggs represent the best amino acid matches for our proteins, and thus are considered the highest quality. While the “lower quality” plant proteins may be lacking in one or more of the essential amino acids, as a group they do contain all of them. The concept of quality really means the efficiency with which food proteins are used to promote growth. This would be well and good if the greatest efficiency equaled the greatest health, but it doesn’t, and that’s why the terms efficiency and quality are misleading. In fact, to give you a taste of what’s to come, there is a mountain of compelling research showing that “low-quality” plant protein, which allows for slow but steady synthesis of new proteins, is the healthiest type of protein. Slow but steady wins the race. The quality of protein found in a specific food is determined by seeing how fast animals would grow while consuming it. Some foods, namely those from animals, emerge with a very high protein efficiency ratio and value.1