If you look at the nutrition information of most top-selling BCAA supplements you’ll see that they claim to have zero calories.
How is this possible?
Does this mean you can drink BCAAs without gaining any weight?
And what about taking BCAAs during intermittent fasting?
Presumably, something with zero calories cannot break your fast…
After all, fitness magazines have been telling us to prevent muscle breakdown by taking BCAAs before early morning fasted cardio for years…
How Do BCAA Supplements Have Zero Calories?
Sadly, all is not what it seems.
What you see here is a necessity under current FDA regulations, which state that supplement manufacturers cannot list the protein content of a supplement when it only contains free form amino acids.
“Protein shall not be declared on labels of products that, other than ingredients added solely for technological reasons, contain only individual amino acids.”
BCAA supplements do indeed contain calories, it’s just that supplement companies are currently unable to list them.
How Many Calories Are In BCAAs?
You may have heard people refer to branched chain amino acids as “the building blocks of muscle”.
It’s a popular term which has been used in muscle building magazines and bodybuilding culture for quite some time.
That’s because BCAAs combine to form protein.
And in free form state, they contain largely the same caloric amount.
Protein contains 4 calories per gram, whereas BCAAs (leucine, isoleucine and valine) come as an incomplete protein source and provide you with around 4.6 calories per gram. (1)
BCAA Myths Answered
So now we can clearly answer three of the big questions which always surround BCAA supplementation.
- Can you drink BCAAs without gaining weight?
BCAAs contain calories, so the answer here is no.
- Can you drink BCAAs during intermittent fasting?
BCAAs are regularly touted as a ‘go to’ source of energy for those partaking in intermittent fasting, with “experts” often citing the fact that branched chain amino acids will fight off fatigue and provide ongoing energy throughout the day. (2)
However, they will also break your fast.
Because calories. So no.
- Should you drink BCAAs before fasted cardio?
“Do 45 minutes of cardio first thing in the morning. Sip on some BCAAs to prevent muscle loss.”
Even though lots of people do this (and this advice is still published in fitness magazines to this day!), this is another myth.
There is nothing wrong with consuming BCAAs before cardio.
It will indeed prevent muscle breakdown, although you’d need to be tackling a ridiculously hard endurance program to even worry about this. (3)
But the cardio you’re about to perform won’t be classed as fasted, because – once again – BCAAs contain calories.
So there you have it!
The next time you see the label of a BCAA supplement claim it contains zero calories, now you know why! If the industry regulations change at any point in the future, I’ll update this article to confirm it.
- May, M. E., et al. Energy content of diets of variable amino acid composition. Am J Clin Nutr. 1990 Nov;52(5):770-6.
- 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. 104(5), 787-794.
- 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. 302(5), E510-E521.