Egg whites and whey protein are two of the most beneficial sources of protein when it comes to building and maintaining lean muscle. Both are complete sources of protein, meaning it contains all the essential amino acids. Essential amino acids are critical to cell and tissue health and the only way to get them is through your diet. Check with your doctor before trying whey protein supplements.
The advantage egg whites offer over whole eggs and whey protein is that it's a fat-free protein source. It does contain small amounts of vitamins and minerals, such as riboflavin, niacin, B-vitamins, potassium, magnesium, calcium and iron. Each raw egg white from a large egg contains about 17 calories, according to the U.S. Department of Agriculture Nutrient Database. Most importantly, each egg white contains about half the protein of a whole egg, which equates to 3.6 g of high-quality protein in a large egg.
Whey is the liquid part of milk protein derived during the cheese-making process. It's a highly-absorbable source of protein that's available in supplement form. Like egg whites, whey protein is a complete protein source. However, it contains a greater concentration of branched-chain amino acids, BCAAs, compared to egg whites. BCAAs are particularly important for muscle development and health. The three BCAAs are leucine, isoleucine and valine.
One way to compare protein is looking at biological value, BV. The BV of a protein measures its overall absorption and utilization quality once consumed. Whey protein has the highest BV of any protein but egg whites are not far behind. The BV of whey protein is 104; the BV of eggs is 100, according to a 2004 report published in the "Journal of Sports Science and Medicine." Other proteins are inferior to these proteins in regard to BV. For example, soy protein has a BV of 74 and casein a BV of 77. Behar states that egg whites have a higher BV compared to egg powder proteins, which score at 91.
It is important to vary the types of protein you consume each day and most of it should come from whole foods. Whey protein supplements feature superior BV and BCAA content; however, it cannot replace whole food sources of protein that contain other essential vitamins and minerals. Consult your doctor to determine if whey is right for you. It may not be the best choice if you suffer from milk protein allergies or are lactose intolerant.