Protein consumption what I learned: a six-time Mr. Olympia's state-of-the-art guide to protein supplements

Flex, Jan, 2004 by Dorian Yates, Brian Batcheldor

Straight after the '92 Olympia, I had to be available for photo shoots, so I couldn't allow my condition to wane too much. Being so drained and having to constantly train on the move, I instinctively increased my carbs slightly. I immediately became aware of improvements in size, fullness and, believe it or not, condition. I also changed to a new protein supplement, not for any other reason than the fact that many of the other guys were using it at the time. Until that point, I had been gulping down large amounts of whey isolate between my meals. The new product I tried was based on whole milk proteins, which include both casein and whey.

Previously, during the final stages of my preparation, I had been tired and found it hard to maintain focus. Fatigue would set in early in my workouts, even though they were of short duration. My muscles constantly felt sore, even to the point of sometimes requiring an extra day's rest between workouts. I had always attributed this to the simple fact that my carbs were so low. When I changed to the whey/casein protein blend, I immediately noticed that I was better able to offset fatigue and that my recuperation was dramatically improved. It made me contemplate how these two seemingly subtle shifts (a slight increase in carbs and the protein change) could contribute so greatly to the changes in my physique.

One possible explanation is that a high-protein diet, particularly when combined with a very low carbohydrate intake, results in a rapid and long-lasting acidic environment. This metabolic acidosis induces a negative nitrogen balance by increasing protein breakdown and/or decreasing protein synthesis, specifically in skeletal muscle. It's believed by some experts that this may be responsible for reduced high-intensity exercise performance during a low-carb diet (and probably was, in my case).

I was able to resolve this by switching to a supplement derived from whole milk proteins. Because whey protein is absorbed so fast, a substantial portion of its amino acids are metabolized for energy. This can lead to increased acidity in the body. Because casein is digested more slowly, it may help to prevent some of the acidic metabolites that can form from protein metabolism.

Several years later, developments in dietary protein science would further explain the advantages of a supplement made from whole milk proteins. Examining the scientific concept of dietary "fast" and "slow" proteins, the latest research indicated that although whey was better than casein at stimulating protein synthesis, only casein inhibited protein breakdown. These studies unintentionally spawned the whey/casein controversy.

SLOW AND FAST PROTEIN This isn't about good and bad proteins; whey and casein each have their advantages. I've already pointed out that I use a special hydrolyzed whey product postworkout, when a rapid delivery of protein is most important.

Knowing when and how to use each is critical to bodybuilding success. When you think of casein or whole milk proteins, think "slow," as this type of protein is absorbed at a slow and steady pace over time. Milk proteins are absorbed more slowly than whey protein because milk proteins tend to clot in the stomach. They take longer to digest and, therefore, you get a slow stream of amino acids. Protein products with casein or whole milk proteins are best used during the day when your next protein meal may be more than three hours away and also right before bed.