What is the Protein Efficiency Ratio (PER)?
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4 min read
The protein efficiency ratio (PER) is a historical method for evaluating a protein's nutritional quality, based on how effectively it supports growth in test subjects. While it was once a standard for nutritional labeling, particularly in the U.S. and Canada, its use has been largely superseded by more advanced methods. This bioassay involves feeding a specific protein to a test animal, typically a rat, and then comparing the animal’s weight gain to its protein consumption over a defined period.
