Protein efficiency ratio (PER) is based on the weight gain of a test subject divided by its intake of a particular food protein during the test period.
], the PER had been a widely used method for evaluating the quality of protein in food.
[1] The official method for determining the protein efficiency ratio is from Health Canada's Health Protection Branch Method FO-1, October 15, 1981.
[2] The U.S. Food and Drug Administration now uses the Protein Digestibility Corrected Amino Acid Score (PDCAAS) as the basis for the percent of the U.S. recommended daily allowance (USRDA) for protein shown on food labels.
The US FDA official methods to calculate the PER are as stated in the Official Methods of Analysis of AOAC International, 16th ed.