Why You Should Never Use BCAAs Before Fasted Cardio

Fitness magazines have spent the last few decades telling us to “drink BCAA supplements before doing fasted cardio in order to prevent muscle breakdown”.

They also claim it can provide you with more energy.

What they don’t mention, of course, is that doing so means you are no longer doing fasted cardio at all!

The Fasted Cardio BCAA Myth

If your goal is to perform fasted cardio, then that means training on an empty stomach.

So it’s worth knowing that a typical BCAA supplement contains around 4.6 calories per gram, and a 30g serving would be around 140 kcals, which would break your fasted state.

Now, I know many of you will be saying:

“Hey Russ, my BCAA supplement says it has zero calories!”

Well, that’s not really the case.

You see, they’re simply taking advantage of an old food industry loophole which states that manufacturers do not need to list the calorie contents of protein in raw amino acid format. (1)

In terms of real foods this is usually a negligible amount of calories, but for a BCAA supplement it accounts for the whole damn product!

So right out of the gate, even before we discuss any of the supposed training benefits they offer, it already means you are no longer performing fasted cardio, and this is likely a deal-breaker for most people because it destroys the whole purpose of using BCAAs prior to training.

But wait, the suck gets even worse…

If you are eating enough protein per day you likely don’t need a BCAA product at all, because you’re already enjoying the benefits of a maximizing your BCAA intake (more energy, more muscle) via your diet.

Also, consuming them as part of a pre-workout supplement can see them clash with other popular pre-workout ingredients like caffeine, leading to early central nervous system fatigue and a feeling of sluggishness. (2)

Fuck that with a capital fist.

Further Reading:

If you enjoyed this blog, then you’ll probably also like reading these.

>> The Ultimate Guide To HIIT
>> Does Fasted Cardio Burn More Fat?
>> Why Do BCAA Supplements Claim Zero Calories?

References:

1. May M. E., et al. Energy content of diets of variable amino acid composition. Am J Clin Nutr (1990).
2. Choi, S., et al. Oral branched-chain amino acid supplements that reduce brain serotonin during exercise in rats also lower brain catecholamines. Amino Acids (2013).