Picking the Perfect Protein

Look beyond the label to choose the right protein powder to optimize WOD performance.

Rob Wildman, PhD., RD September 05, 2014

Protein has never been as popular as it is now. As a nutritionist, I find it interesting that so many myths about protein have come and gone, including the one that held that all any adult needed was the Recommended Daily Allowance, regardless of how much he or she trained, and that if you ate more protein than that, your kidneys and bones could be in danger. Obviously, a lot has changed, and in recent years, it has become clear that athletes like CrossFitters need more protein daily and that higher intakes are indeed safe. 


In addition to high-protein foods, many athletes rely on protein supplements to strategically supply their muscle postworkout as well as to support greater daily needs. However, with so many protein supplements on the market, one of the most common questions I am asked is which one to buy. Below are some guidelines to assist you in picking the right protein.

The King of Performance Nutrients

Protein makes up roughly 80 percent of muscle mass (once the water is removed) and is responsible for muscles’ structure and action. That’s why protein intake is viewed by all athletes (including CrossFitters) as absolutely critical to optimizing muscle size, strength and performance. And when it comes to protein supplements, the bottom line is that people who train seriously use protein supplements specifically to support muscle building and the development of strength, power and endurance in response to WOD training. With that said, how do you know that all the protein claimed on Supplement Facts labels is capable of promoting those positive changes in muscle size and performance?

Supplement Facts and Fallacies

Most consumers take the protein amount listed on Supplement Facts labels as an absolute, meaning that it constitutes all the protein that can contribute to muscle growth. However, some brands might have added amino acids like taurine, alanine and glycine or amino-acid-derived ingredients like creatine and count them as protein. They’re able to get away with this because all those additional nutrients contain nitrogen, which is the factor used by laboratories to estimate how much protein there is in a product. It’s then up to the brand to honestly label how much “real protein” is in each serving by subtracting out “nonprotein nitrogen” (e.g., added amino acids, creatine, etc.). 

The further problem is that while those bonus ingredients have their own benefits, they don’t have a lot to do with muscle growth or performance benefits. Taurine is an amino acid, but it doesn’t get used as a building block for protein. Glycine and alanine can indeed be used to make protein, but they are nonessential amino acids, and any extra your body gets is probably going to be used for energy purposes instead. And although creatine is derived from amino acids, it cannot be converted back to amino acids to make muscle protein. Taken together, this means that these extra sources of nitrogen, which might be labeled as protein, will not contribute to muscle-protein manufacturing. Said differently, even though there might be more protein per serving in certain protein powders, that might not result in more muscle-protein manufacturing.

Leucine: The Mark of Real Protein

So how can you know that the protein you’re taking is high quality and delivered in an efficacious level per serving? One standout marker is leucine, an essential branched-chain amino acid. Leucine is critical for muscle-protein production in response to training, and it seems to help maximize the mechanisms that “trigger” or stoke muscle-protein manufacturing and that result in strength, power, endurance and size development. In fact, some researchers have suggested that it takes at least 2.5 grams of leucine (or 5 grams of BCAAs) to maximally stimulate muscle-protein-manufacturing systems. So to make sure you’re getting maximal muscle- and performance-boosting impact from your supplement, look for call-outs for leucine content, as well as total BCAAs, on the protein powder’s label.  

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About the Author

Rob Wildman, PhD., RD

Rob Wildman, Ph.D., RD, is the author of Sport and Fitness Nutrition and The Nutritionist: Food, Nutrition, and Optimal Health and is the creator of TheNutritionDr.com. Follow him on Twitter: @TheNutritionDoc.