Is Intermittent Fasting BCAA Necessary?

Is Intermittent Fasting BCAA Necessary?

By Dr Joe

Is Taking BCAAs During Intermittent Fasting Necessary?

So, I get asked often this question: Is taking BCAAs necessary during intermittent fasting? Framed in another way: Is intermittent fasting BCAA necessary?

Both questions are essentially needing the same answer. So, let me answer those questions on this page.

intermittent fasting BCAA necessary

But before I answer the question, let me quickly settle this other query: Can you have BCAAs while fasting?
That seems to bog a lot of people too, but that’s okay. My blog was created to solve questions.

So, can you take BCAAs during fasts?

Answer: Yes, you can take BCAAs during your fast, but it’s always better to take your BCAAs towards the end of your fast.

Why is that? Well, BCAAs do have a calorific value. That means in essence, taking BCAA supplements, you are technically breaking your fast.

But only to a small degree. See my detailed answer here.

Okay, now that we have established that you can take BCAAs during your fast, let’s get on with the main event of this page.

Is intermittent fasting BCAA necessary?

The answer to that is Yes and No.

Okay, now you are thinking, Dr Joe is hedging his bets here.

No, I am not. Because there are arguments on both sides of the divide.

As I am not one to shy away from a scientific argument, I’m going to explain why you may or may not have intermittent fasting BCAAs.

Whether you should take BCAAs during intermittent fasting depends on what you are trying to achieve, in the first place.

Okay, let me explain. I will start with the ‘Yes, you do’ and finish up with the ‘No, you don’t’

Yes, you do need bcaa supplements during intermittent fasting…why?

Here is why.

If muscle gain and fat loss are your objectives for doing intermittent fasting, then yes, you need BCAAs.

Don’t forget that not everyone wants to sculpture their body with intermittent fasting. Some people just want to lose weight (lose fat) without bothering with muscle gain.

BCAAs are amino acids. Amino acids are the building blocks of proteins. Muscle is mainly made up of proteins.

If you are going to build muscle, you are going to need proteins. Lots of it.

There are people whose diet may not be as sophisticated as those in the fitness know. In which case, they may not consume the required dietary amount of proteins necessary for a good muscle build.

BCAA supplements will bridge that gap in these individuals.

Of course, you are going to work out if you desire muscle gain. Good resistance training to build muscle. I don’t need to tell you that building muscle will require some serious lifts. No Pain, No Gain is the well-worn out parlance, right?

Go gently though, to avoid injuries. But to reach your muscle gain goal, you will need to exercise about 3 times a week with rest days to allow your body to recover.

Do you need to workout more than 3 times a week? You may. But you wouldn’t want to do it more than 4 times a week at a push (no pun intended).

Like I said earlier on, to build new muscle and even to preserve existing muscles, you need proteins. And proteins are made up of amino acids inclusive of the branched-chain amino acids in BCAAs.

Here are the advantages of using Intermittent Fasting BCAAs

  1. Intermittent fasting BCAAs help with Protein Manufacture
    The muscle cell is called a myocyte.

Myocytes are one of the most metabolically active group of cells in the body. There is constant breakdown of amino acids by a process of oxidation inside the myocyte (muscle cell).

The more activity the muscle cells are engaged in, the higher the level of breakdown of protein that will occur.

Any breakdown of protein inside will have to be replenished. Without that, muscle loss will occur.
This research tells us that indeed, exercise is one thing that generates a lot of oxidative activity inside the muscle cell.

But that’s not all, that study is also telling us the BCAA requirements do go up during exercise.

If we then agree that essential amino acids requirements inside the muscle cell increases during exercise, then taking BCAAs for workout purposes during intermittent fasting won’t be a bad idea.

We will simply be replenishing the amino acids our muscle cells are burning during workout when we are fasting.

This is particularly important if we are working out when we haven’t broken our fast during intermittent fasting.

intermittent fasting bcaa protein manufacture


In fact, that study did conclude thus:

“BCAA supplementation before and after exercise has beneficial effects for decreasing exercise-induced muscle damage and promoting muscle-protein synthesis”

2. Intermittent fasting BCAAs reduce Muscle soreness

You and I know that when you exercise, you may experience muscle soreness usually about 36 – 48 hours later. It’s called; Delayed-Onset Muscle Soreness (DOMS).

It happens to everyone. Of course, the more trained your muscles are, the less the effect of DOMS.

For those who are not so well trained in terms of physical fitness, muscle soreness can actually become a discouraging factor not to exercise. Not what you want if you are keen to build muscle.

But the fact is; muscle pain can reduce your frequency of exercise against your will.

Now, if you are doing intermittent fasting and you want to build muscle at the same time, the last thing you want is infrequent training regimes.

Here comes, BCAAs to your rescue.

This study took untrained participants and subjected them to squat exercises. You know how squats can make you walk funny a couple of days later because of muscle soreness.

The group that had BCAA supplementation in that study had reduced muscle soreness compared to the placebo group. This led the researchers to conclude that muscle damage during exercise is actually suppressed by BCAA supplementation.

So, if you want to exercise whilst doing say for instance, 16/8 intermittent fasting, then BCAA supplementation is necessary for you to avoid delayed-onset muscle soreness.

3. Intermittent fasting BCAAs limit muscle damage at workouts

You are doing intermittent fasting, working out and are now wondering if taking BCAAs during your intermittent fasting is necessary to limit muscle damage.

Yes, BCAAs do limit the degree of muscle damage that occurs during workouts. It really doesn’t matter whether you are fasting or not. BCAAs limit muscle damage from exercise regardless.

But it becomes more important when you are fasting. Exercising at the time of intermittent fasting means you are exercising at the time of calorie restriction.

So, if you take a supplement that feeds your muscle with the necessary essential amino acids it needs to prevent muscle damage, wouldn’t that be a good thing?

I sure think so.

There are biological markers that can correctly indicate muscle damage following exercise. Markers like creatine kinase and lactate dehydrogenase.

If a sample of blood is taken from you following an exercise session, we can tell how much muscle damage had taken place in that session.

That’s because damaged muscle releases markers like creatine kinase, myoglobin, aldolase and lactate dehydrogenase. Measuring any combination of these markers will reveal the degree of damage.

Give one groups of individuals BCAA supplements for 14 days. Pitch them against another group not given BCAA.

Now make the two groups perform 2-hour cycling workout. Test the creatine kinase and lactate dehydrogenase levels in both groups. That’s what this study did and they found that creatine kinase and lactate dehydrogenase levels were significantly lower in the BCAA supplemented group.

The point is; BCAA supplements are protective of muscle damage.

So, it makes sense to use BCAAs whilst doing intermittent fasting to limit muscle damage when we exercise to tone up and gain muscle.

4. Intermittent fasting and BCAA may stimulate muscle growth

There is a study that appears to support the view that working out in the fasted state is beneficial for muscle growth.

This study should be important to you, if bodybuilding to whatever degree, is something you desire.

Indeed, you don’t have to bust a gut to get anabolic response going according to that study. Simple weight training exercise like bench press, leg press, curls and overhead press are just about enough to experience muscle growth.

It’s a cross-over study with a 3-week washout to remove the confounding factor of one intervention influencing the outcome of the previous intervention.

The outcome measure of the study was anabolic response in the fasted state Vs in the fed state.

Put in another way, the question being answered in the study was: does the protein synthesis signalling pathway get activated more when you eat before workout or more when you workout in fasting state?

The study was quite involving because the researchers actually took needle biopsies from the participants at rest, 1 hour and 4 hours post-exercise.

The researchers were measuring markers like PKB (protein kinase B), GSK3, p70s6k (p70 ribosomal S6 kinase), eIF2B, eEF2 (eukaryotic elongation factor 2), ERK1/2, and p38.

Don’t worry. You don’t need to know what those hard-to-pronounce biological markers are.

All you need to know is that; exercise does stimulate those markers to varying degree. Measuring them can give a good idea as to what is happening inside the muscle cell.

To cut a long story short, a higher anabolic response was seen in the intermittent fasting participants at the 1-hour mark.

What this means?

I have already mentioned that muscle breakdown does occur during exercise because of the oxidation of amino acids that make up protein.

This protein catabolism is inevitable.

protein synthesis signalling


Here is where I think that last study makes intermittent fasting BCAA use necessary.

It is expected that the inevitable protein catabolism that occurs in the muscle during exercise may be a little higher when you exercise in the fasted state.

Why…Because the muscle is sort of “hungry” in the fasted state and now you pushing it harder to do some more work.

If we now know that the anabolic response (which gives us the potential for muscle growth) is higher when you exercise in the fasted state, at least at the 1-hour mark, would it be a bad idea to feed the muscle with BCAA amino acids 30 minutes before exercise?

I think it is a great idea.

Feed the muscle with intermittent fasting BCAA before exercise – this reduces protein breakdown activity in the muscle during the workout session.

Eat soon after the exercise session, preferably a high protein meal as they did in the study and voilla, you’ve got yourself a recipe for serious muscle growth direct from a well-defined enhanced anabolic response.

Is that cool or what.

Now, that’s why I think BCAAs are necessary for intermittent fasting.

The case for; No, BCAAs are not needed

Spoiler alert.
I have just made what I consider to be a compelling case for use of BCAA supplements in intermittent fasting.
Now I have to ruin it by making the case against.

Oh yes, we like a balanced argument, don’t we?

For me, the case for not using BCAAs during intermittent fasting is simple.

If you doing intermittent fasting and your intention is fat loss only without bodybuilding, then you don’t need BCAAs. Period.

You can lose weight with intermittent fasting without using bcaa supplements. In fact, they are not necessary at all, if fat loss alone is your objective.

So long as…

…your diet is rich enough with proteins.

The amino acids in BCAA are actually available in your food. See list of foods rich in bcaa here.

If you are getting a rich supply of amino acids from your high protein food, then you will do just fine without bcaas.

I will even go as far as saying that even for those into body building, you can still source your amino acids for muscle growth from having eating a high protein diet around your workout session and you will still get fairly good results.

It’s just that BCAAs are supplements and supplements are easier to take as they are less bulky.

You can look at BCAA use in intermittent fasting in those two ways.

Use intermittent fasting BCAAs if fat loss and bodybuilding is what you want. They are easy to use. They are convenient. They facilitate muscle growth if you use the BCAAs around your workout session. They reduce muscle breakdown too.

If you are not into bodybuilding and you just want to lose weight i.e lose fat, then you don’t have to use BCAAs. You can get by without them.

Let me know what your experience is when you use them or even when you don’t, by leaving me a comment below. Just scroll down and leave your comment.

You may be interested in coffee effect on fasting too. Go see it through that link.

Suggested further reading:
7 “Fatty Foods” for a Flat Stomach – delicious but healthy