Last updated:

25 July 2023

They’re essential for muscle growth, but how do BCAAs have no calories? There’s no magic at work, rather a food industry loophole. Here’s the details.

how do bcaas have no calories

Reading time:

2 min read

If you’ve ever looked at the back of your tub of BCAAs, you may be surprised to see that they have ZERO CALORIES listed on the nutrition label.

What kind of evil sorcery is this?!

Does this mean you can drink BCAAs all day long without gaining weight?

Unfornately not.

In reality your BCAA supplement actually does contain calories but current supplement industry regulations stipulate that nutrition labels cannot show the calorie content of incompete proteins. BCAA supplements contain free-form amino acids, which fall into this category.

Here’s what the FDA have to say:

“Protein shall not be declared on labels of products that, other than ingredients added solely for technological reasons, contain only individual amino acids.”

how do bcaas have no calories


The 3 branch chain amino acids (leucine, isoleucine and valine) contain roughly 4.6 calories per gram. (1)

That’s about the same as a gram of protein, so it’s easy to work this into your nutrition targets.

Now that we know this, we can use this information to debunk some of the most common questions relating to BCAAs supposedly having “zero calories”:


No, because 30 grams of BCAAs contains about 120 calories. Cuz calories!


Muscle building magazines regularly advise us to drink BCAAs during our fasting window in order to prevent muscle breakdown and fight off fatigue. This is BS advice.

First off, you’d need to have the training routine of a damn Olympian to be concerned with muscle breakdown. (2, 3)

Secondly, drinking BCAAs in your fasting window will break your fast. Cuz calories!


Some people say you should drink a BCAA supplement before fasted cardio to avoid muscle breakdown.

BCAAs would indeed prevent this (although any potential muscle loss would be minuscule), but drinking thos BCAAs means you are no longer performing FASTED cardio. Cuz calo-f**king-ries!

how do bcaas have no calories


  1. May M. E., et al. Energy content of diets of variable amino acid composition. Am J Clin Nutr (1990).
  2. Portier H., et al. Effects of branched-chain amino acids supplementation on physiological and psychological performance during an offshore sailing race. Eur J Appl Physiol (2008).
  3. Borgenvik M., et al. Intake of branched-chain amino acids influences the levels of MAFbx mRNA and MuRF-1 total protein in resting and exercising human muscle. Am J Physiol Endo Metab (2011).

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  1. Richard avatar

    Thank you so much!

  2. Tony Best avatar
    Tony Best

    Used to do the BCAA fasted cardio thing myself. You live and learn, eh Russ, thanks!

  3. Carl avatar

    Ahhhhhhh always wondered about this!

  4. Rachael avatar

    Argh! The fasted cardio thing is me. I did that. Never even connected the dots. Thanks, Russ!

  5. Norma avatar

    Wow that was unusual. I just wrote an incredibly long comment
    but after I clicked submit my comment didn’t show up.
    Grrrr… well I’m not writing all that over again. Regardless, just wanted to say wonderful blog!

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