Leucine, Whey and Rice Protein

In January, I made a post saying that there was scant evidence that branched chain amino acids (BCAA) are important for sports nutrition (Branched Chain Amino Acids and Exercise). In response, a reader, who is a bodybuilder, told me that while BCAAs might not be important, leucine (one of the three BCAA) is likely important and is probably the reasons why whey protein powder has been shown to be better than soy for building muscle.

The reader passed on some abstracts and I found some others.

One was a study that showed that after 12 weeks of exercise in untrained men, 4 g/day of leucine led to a 41% increase in strength compared to a 31% increase for the placebo which was lactose. There were no differences in muscle mass. Okay, but is a 10% greater increase in untrained men really enough to worry about? Assuming that just eating 4 more grams of protein per day wouldn’t be just as good, I’d be surprised if the lactose group wouldn’t catch up if given a few more weeks of training.

Another two abstracts were studies comparing whey protein to soy: one in older men (2) and one in younger men (3). Both were simply measuring muscle synthesis one time after one bout of exercise. Free versions of both studies are linked from the abstracts below (I didn’t bother reading them). I don’t think these studies prove much and I don’t know if there are more impressive studies showing whey protein to be superior to soy.

Then in March, a study was reported that showed that rice protein was as effective as whey protein in increasing muscle mass (4). As of today, it does not appear to have been published in a peer-reviewed journal. This study was better designed (for our purposes) in that it was done on men who had been already involved in weight training. It was double-blinded and after 8 weeks of supplementing with one of the proteins at 48 g/day, there was significant increases in strength and muscle mass. There was no placebo group so who knows if either type of protein was necessary – perhaps just taking part in a study would be enough motivation to work out harder and have some gains in muscle mass.

In short, I don’t think there’s anything to worry about for vegan bodybuilders who are concerned that their soy or rice protein powders are not giving them the same edge as bodybuilders using whey protein.

Please note that I am not philosophically opposed to the idea that plant proteins might be inferior or to supplementing for better athletic performance. I think there is good evidence that elite vegan athletes might benefit from creatine (for recreational athletes, creatine’s probably not worth the hassle). But one should be very skeptical when it comes to sports nutrition supplements – there is a lot of money and enthusiasm behind finding supplements that can improve performance, but most turn out to be useless.

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1. Ispoglou T, King RF, Polman RC, Zanker C. Daily L-leucine supplementation in novice trainees during a 12-week weight training program. Int J Sports Physiol Perform. 2011 Mar;6(1):38-50. | link

2. Yang Y, Churchward-Venne TA, Burd NA, Breen L, Tarnopolsky MA, Phillips SM. Myofibrillar protein synthesis following ingestion of soy protein isolate at rest and after resistance exercise in elderly men. Nutr Metab (Lond). 2012 Jun 14;9(1):57. | link

3. Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol. 2009 Sep;107(3):987-92. | link

4. Dutch, A. First Double Blind Study Proves Plant-based Rice Protein Has Identical Benefits To Animal-based Whey Protein. PR Newswire. March 11, 2013. | link

14 Responses to “Leucine, Whey and Rice Protein”

  1. Mike Says:

    Any studies on the benefits of (mixing) rice and pea protein isolate?

    I thought the combination of the two was advantageous i.e. both complement each other with regard to the amino acid profile and there is the absence of an insulin spike compared to using whey.

  2. Jack Norris RD Says:

    > Any studies on the benefits of (mixing) rice and pea protein isolate?

    I haven’t seen any.

  3. James Says:

    I guess the other question is, is protein supplementation of any kind, plant or animal, beneficial for strength training?

  4. Jack Norris RD Says:


    > is protein supplementation of any kind, plant or animal, beneficial for strength training?

    It’s been awhile since I updated this article, but here is what I wrote a number of years ago:


  5. Michael Says:

    A lot of people (not just vegans) swear by Vega’s sports line. Do you think it’s overrated?

  6. Jack Norris RD Says:


    > A lot of people (not just vegans) swear by Vega’s sports line. Do you think it’s overrated?

    I don’t know what it’s claimed to do, but like for any energy bar, I’d be surprised if it improves sports performance compared to other options like, say, a bagel with peanut better before working out.

  7. Jack Norris RD Says:


    I want to correct my comment. I see that the Vega One par has 15 g of protein. That is going to be more beneficial to building muscle than a smear of peanut butter on a bagel. If your goal is building muscle then a 15 g/protein energy bar is better than something with a lot less protein, other things being equal. If you’re off to do any other type of sport (other than, perhaps, short distance sprinting), then a bagel with peanut butter should work similarly.

    And it does have a lot of vitamins and minerals, so if you are lacking them in the rest of your diet, I can see it being beneficial. It says it contains 3 µg of B12 and lists “vitamin B12” as an ingredient. Hopefully it is not B12 from an algae or seaweed.

  8. Dan Says:

    Is there any evidence that protein loading for bodybuilding actually helps to build muscle tissue or strength? It seems to make physiologic sense, but I wonder if it has ever been empirically tested, e.g. by kinesiologists / exercise physiologists / nutritionists.

    Older teaching was that high protein loads were bad for the kidneys, especially those with pre-existing renal impairment. High protein loads also carry a lot of phosphate and organic acids during breakdown/metabolism/excretion. I don’t know if they still teach this ‘dogma’, or if it was ever even true or not.

    As to the peanut butter and bagel, I would never touch it. The bagel that is! The peanut butter is fine and dandy, but the processed carb junk needs to stay out of the bodybuilder’s diet.

  9. Dan Says:

    I’ve been thinking a bit more about the role that DHA may play in cognition.

    It seems to me that many ancient cultures produced a record of remarkable achievement despite very little contact (if any) with DHA-rich marine seafood.

    I think in particular of the Aztecs and Mayans, who were able to calculate solar eclipses and other celestial events hundreds of years into the future, and built pyramids, roads and modern sewerage with potable drinking water; the Pharaonic Egyptians, who had equally remarkable achievements in art, agriculture, medicine and architecture; and the Han Chinese, who invented gunpowder, intercontinental sailing and astronomy well before anyone in maritime Europe did.

    These 3 cultures were based on the cultivation of maize, wheat, and rice, respectively. As far as I know, and in particular in dense inland populations, they would have had little access to omega-3-rich marine seafood. Yet they were able to produce great accomplishments which obviously required superb cognitive abilities.

    Similar with the Sumerians in ancient Iraq. They invented writing (on clay tablets), record-keeping, municipal laws, beer, grain storage and a high priestly class. They were heavily grain-based, with very little access to seafood, particular in the interior of the country (remote outlying regions like Basra on the Persian Gulf might have had more access, but there was no way to ship or distribute highly perishable seafood in those days).

    So that is four cultures which gave the world incredible heritage of achievements and whose diets contained 0% DHA.

    I wonder therefore if it is necessary for vegans to supplement with DHA at all.

  10. Jack Norris RD Says:


    I wouldn’t take the fact that some segment of the population was intelligent to mean that the intelligence of the average person was just as high as the average DHA-replete individual is today. And who knows what the DHA levels of the most intelligent were or why.

  11. Dan Says:

    Well, it’s a bit like Ansel Keys’ 21-Countries Study, comparing the association of national saturated fat intake with national rates of coronary artery disease deaths. Or the recent paper by Messerli in NEJM showing that per capita chocolate intake is associated with the number of Nobel laureates each country produces.

    What I meant was the following: highly agrarian, landlocked societies with population centers far from DHA-rich marine fish produced staggering civilizations (Aztecs, Incas, Mayans, Pharaonic Egypt, Mesopotamia, China). The Aztecs even had indoor plumbing and flushing toilets. The Mesopotamians thousands of years ago had municipal laws and temples with priests. And so forth. These cultures could not have had high DHA levels in *anyone*, let alone some supposed hyperintellectual elite responsible for these hallmark achievements.

    Contrast those achievements with cultures that were seafaring and consumed large amounts of omega-3 rich fish – and didn’t produce much of a civilizational record of remarkable accomplishments standing the test of time – such as the Maori from New Zealand, Polynesians from the south Pacific, the Inuit from Greenland, and the Unangan Aleuts from the Aleutian Islands. This may sound like snobbery, and I’m sure all of these primarily seafood-based cultures were exceptionally well-adapted to their local habitats, but in terms of the production of written language, monumental architecture, lasting art, and scientific discoveries (mathematics, algebra, astronomy), non-Maritime agrarian cultures beat them hands down every time. And these are the accomplishments that have been passed down to us today in our modern societies, not the ability to handcraft a canoe or net a bunch of sturgeon.

    Just making a cultural/ecological argument that we probably don’t need DHA to thrive intellectually.

  12. Jack Norris RD Says:

    > Is there any evidence that protein loading for bodybuilding actually helps to build muscle tissue or strength?

    I’m not sure what you mean by “protein loading” exactly, but there is plenty of evidence that eating more protein than the RDA can help build muscle tissue for bodybuilding:


  13. David Says:

    Does creatine cause hair loss and why is it not worth the hassle?

  14. Jack Norris RD Says:

    > Does creatine cause hair loss

    No idea.

    > and why is it not worth the hassle?

    If you are not a competitive athlete, then you are taking a (slight) risk with your health and adding expense and time to something that, even if it were to improve your performance would probably not be terribly noticeable. For example, I think it would be generous to say that creatine could improve someone’s strength by 10%. So instead of bench pressing 200 lbs, you could bench press 220 lbs. Is that worth it? If it is, then be my guest. I have decided for myself that the benefits are creatine are not worth it as I find them barely perceptible when I even perceive them at all.

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