Although I wrote an extensive article about egg nutrition and controversies in the March 2017 issue of Applied Metabolics, I recently found two new studies presented at a recent major medical conference that also explored the anabolic potential of eggs for those engaged in bodybuilding or weight training. As I noted in my article about eggs, prior to the advent of whey protein supplements eggs were considered the best natural protein source. Protein supplements popular in the 70s, such as Blair's protein, contained a combination of milk and eggs since both protein sources showed high biological value and ease of absorption. But egg protein supplements existed back then, and still do today. However, current egg protein supplements are often composed of only egg whites, rather than whole eggs. Indeed, many bodybuilders will consume egg whites and throw away the yolk portion. Ostensibly, the rationale for this practice is that egg whites are nearly pure protein devoid of both fat and carbohydrates. As such, that makes them ideal for diets having the goal of body fat loss. What isn't considered, however, is that nearly all the other nutrients found in eggs--including half the protein content--exists in the yolks. From a nutritional point of view, there is no rational reason to discard egg yolks. Although the yolks do contain some saturated fat, the largest fat content of egg yolks is monounsaturated fat. This is significant because monounsaturated fat, which is the same type of fat found in olive oil and most nuts, has a low tendency to be converted into body fat in those who exercise. Furthermore, this type of fat will not inhibit fat loss on any type of diet.
But no matter how much evidence of the benefits of egg yolks are presented to bodybuilders and athletes, they still continue to consume only egg whites. I think this is more a matter of what psychologists call "confirmation bias," than anything else. Simply put, bodybuilders have been ingesting only egg whites for so long that they cannot accept any other alternative, such as consuming whole eggs, despite being presented with extensive scientific evidence about the advantages of consuming whole eggs. But the two new studies presented recently at the FASEB science conference offer contradictory views on whether whole eggs offer superior anabolic or muscle-building effects over-consuming only egg whites.
In the first study the study authors noted that most studies of the effects of protein on building muscle have involved isolated protein supplements, such as whey. As such, they focused on the anabolic effects of whole food, eggs. The object of the study was to compare the anabolic effects of consuming whole eggs versus egg whites in healthy young men engaged in a weight-training program. The study subjects consisted of 10 men, average . . .