The way that protein in a food or supplement is usually measured is by using the Protein Efficiency Ratio (PER). The protein efficiency ratio for a food is determined in a lab by dividing the weight gain of a test subject who had been given certain types of foods or, more specifically, proteins, by the intake of that particular protein during the test period. In short, a test subject (not always human) ate and gained weight. Then that weight (in grams) was divided by the amount of the specific protein that the subject took (also in grams).

Here is a list of the (PER) of different proteins.

* Whey Protein isolates blends: 110-159
* Whey Concentrate (lactalbumin): 104
* Whole egg: 100
* Cow’s milk: 91
* Egg white (albumin): 88
* Fish: 83
* Beef: 80
* Chicken: 79
* Casein: 77
* Soy: 74
* Rice: 59
* Wheat: 54
* Beans: 49