However, most researchers in exercise science and nutrition believe whey protein’s “man-maker” (It’s a euphemism! I know you don’t need to be a man to want sleek muscles where you may have mushier bits and pieces) benefits stem the branched chain amino acid, leucine.
Leucine is one of the nine essential amino acids (meaning our body cannot produce it so we need to get it in our diet every day) and its one of three branched chain aminos. Research shows that leucine has unique actions on muscle protein synthesis and it may be the one that’s considered the “rate-limiting” amino acid when it comes to helping us become more lean.
In light of the new studies we recently reported about with whey helping us lose fat, gain muscle, readers asked what foods (other than dairy options) contain leucine and in what amounts? I had to admit, I had no idea, but I did know how to find the answer.
Using the USDA Nutrient Database, I searched the best sources of protein and checked for leucine content. The result is the chart below of many popular protein foods. As you can see, dairy foods, fish, poultry and beef are good sources of the BCAA. The list is not comprehensive but it’s just a guide to show you how the various protein options stack up. While one study found that 2.5 grams leucine stimulated muscle synthesis, there are currently no guidelines for how much leucine is required for optimal muscle synthesis, but most researchers recommend 20 grams protein after exercise.
That’s easily achieved with having a cup of cottage cheese, a glass of milk with half a turkey or tuna salad sandwich. Of course, a whey protein supplement will work too, but it certainly won’t have the same nutritional benefits, taste or satiety value of real food. In addition, the leucine content of supplements vary greatly.
When I looked at several whey supplements, they contained varying amounts of leucine. And many contain less than what you get from ‘real’ foods. There are also L-Leucine supplements available but all label the leucine per serving in milligrams to make it seem like there’s more leucine per serving compared to other food sources. Remember, 1,000 mgs =1 gram.
Load Up Your Muscles with Leucine
|Food (serving size)||Leucine (grams)|
|Cottage Cheese (1 cup)||2.9|
|GNC’s AMP Amplified Wheybolic Extreme 60 (1 scoop)||2.6|
|Turkey Breast (3.5 oz)||2.4|
|Chicken Breast (3.5 oz)||2.3|
|Wild Salmon (3.5 oz)||2.0|
|Canned Tuna (3.5 oz)||2.0|
|Haddock (3.5 oz)||1.9|
|Beef “Loin” Cuts (3.5 oz)||1.9|
|Skim Milk (1 cup)||.8|
|Yogurt (1 cup)||1.4|
|Red Kidney Beans (1 cup)||1.3|
|Lentils (1 cup)||1.3|
|Mozzarella Cheese (1 oz)||.67|
|Soybeans (1 oz)||.65|
|1 large Egg||.5|
|Almonds (1 oz)||.4|
|1 egg white||.3|