BCAAs: Effective Dose for Muscle Growth and Fat Loss

Editor’s note: Every month I write a column for Muscle & Fitness magazine called “Born Fit” where I answer real questions. This post focuses on BCAAs, muscle growth, fat loss, and the role of leucine with intermittent fasting. This is an unedited answer without the space restrictions of the magazine. If you want to potentially be featured in the magazine, ask a question using the hashtag #BornFit. -AB 

Should I take BCAAs for muscle growth and why?

Ever since I wrote a book about intermittent fasting, the level of intrigue about BCAAs (branched chain amino acids) hit a new level. I have no one to blame but myself.

I admitted that when I train “fasted” I like to have BCAAs before my workout.

BCAAs are good, but be aware that adding more aminos on top of hitting your protein goals is not likely to spark extra muscle magic.

Unfortunately, this was translated as: BCAAs improve muscle gains, so I should drink them. A lot.

Much like protein dosing, the story of BCAAs is that more is not necessarily better. And in some cases, taking them separately as part of your diet and supplement plan might not even be needed at all.

What Do BCAAs Really Do?

You, see, BCAAs are a collection of three amino acids with a side chain that is branched. They are leucine, isoleucine, and valine (usually in a 2:1:1 ratio).

Leucine itself is known to be an “anabolic factor” and signal for muscle protein synthesis, when calories or protein is low, this anabolic signal appears to help prevent muscle loss or even promote muscle gain.

Naturally, it would make sense to take BCAAs. But your needs depend more on how much protein you’re eating during the day.

You see, while BCAAs tend to be high in leucine, so are all complete protein sources.

So whether you’re chugging down a protein shake or chomping on a steak, you’re taking in BCAAs and a pretty significant dose of leucine.

Here’s where it gets tricky. Most research on BCAAs compares the consumption of the magical three ingredients to low- or no-protein intake at all.

In those scenarios, yes, you want to pump those BCAAs to help prevent muscle loss or even spark muscle gains. So if you’re struggling to eat enough, BCAAs are a great option. But in the few studies that do compare BCAAs to adequate protein there really wasn’t any difference.

Do You Need Extra BCAAs?

What does it all mean? Consume enough protein and there’s no need to worry about purchasing extra BCAAs, which tend to be rather expensive, especially compared to whey.

If you’re eating your protein, the speed of absorption and the amino acid amounts take on secondary importance. Why? The total amount of protein you eat is what matters most in terms of what your body needs to grow bigger, stronger muscles. 

The exception to the rule occurs when you’re dieting or eating fewer calories.

Some research does suggest that taking in more BCAAs might help you preserve your muscle as you drop fat.

It’s not that the BCAAs are better than protein, per se, it’s simply a calorie saving move.

While many BCAA products appear to be “calorie free” don’t be fooled. (This is an FDA loophole where anything that has less than 5 calories per serving doesn’t need to be listed.) One gram of BCAAs is 4 calories. So 10 grams of BCAAs is 40 calories, compared to a 30-gram scoop of protein powder (with a similar amount of BCAAs) would be 120 calories.

At the end of the day, your muscles need and want BCAAs for growth or holding onto muscle when losing weight. But how you receive your BCAAs—from foods, protein powders, or straight BCAA supplements—is ultimately up to your preference and bank account.

Just don’t expect that adding more aminos on top of hitting your protein goals will spark extra muscle magic.


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