Losing Muscle while Dieting

by Brad Pilon

Brad, any ideas of longer term fasting on muscle loss? A week? 2 weeks or more of fasting (assuming strength training of course)?

I get questions like this probably once a day between my personal facebook page, the Adonis Lifestyle fan page and the Venus Index Fan page.

So hopefully this post will serve as my ‘definitive’ answer to questions about losing muscle while dieting or fasting.

And here it is:

I don’t know. Either does anyone else.

I know that anything less that 72 hours doesn’t result in any measurable losses, especially when the appropriate amount of weight training is involved.

Based on this fasting once or twice a week Eat Stop Eat style is not going to cause you to lose muscle.

Most likely the amount of muscle volume or size you lose during long term dieting or fasting depends on your age, sex, amount of muscle to begin with, amount of of body fat,  amount of and type of exercise etc.

It would also depend on how you define ‘muscle loss’ (grams?, ounces?, pounds?, a look? strength?)

If I had to guess (and it’s just a guess) I’d say anything over a week would result in some form of measurable loss in muscle volume.

But this loss in volume would obviously be transient.

Meaning the muscle size would not be gone forever…just like the bodyfat you lose while you are dieting isn’t gone forever…You start overeating the fat comes back…you start eating and training again the muscle will also come back.

So any answer about losing muscle while dieting needs to come with a disclaimer – Any muscle loss would be temporary if you continue to weigh train.

Failure to bring up this point would just add more fuel to the “You need to eat more to lose weight” and “You’ll lose muscle if you diet” scaremongering that’s already way to prevalent in today’s diet advice.



Bill Pairaktaridis April 5, 2011 at 2:18 pm

Why the tag “loosing muscle”? Making mistakes in the tags now, as well? Anyway, good post, Brad. People need to get this through their head. Muscle is not “lost”. It’s just deflated.

Wayne April 5, 2011 at 2:51 pm

I’ve seen some diets promote high protein intake, with minimal carbs. The rationale being that increasing protein will prevent your body from losing that muscle. Is it rationale to believe this is true, or does it just slow the effect down?


Cody April 5, 2011 at 3:30 pm

Great answer. That was my guess, but I was wondering if there was any research on it. Sounds like not.

Brad Pilon April 5, 2011 at 3:43 pm

No, ‘loosing muscle’ is highly searched and typed in my blog ‘search’ function.

Deflated = great term.

Michael April 5, 2011 at 4:34 pm

Took the words right out of my mouth. It is only temporary if you continue to train.

Aaron April 5, 2011 at 4:52 pm

Great post Brad! I get tired of people asking me how I am so lean and once I say I fast a red flag goes off in their mind and they get all frozen up and start busting out all the lame excuses you listed. Guess its just too simple for them.

DebbieJo April 5, 2011 at 8:19 pm

what exactly in calorie wise is fasting—some say under a certain number of calories and you are in the fasting state. I know not eating at all is of course fasting but how low can you go in calories and not be fasting?

Brad Pilon April 5, 2011 at 8:42 pm

For our purpose it’s the purposeful decision no to eat or drink calories for a predetermined amount of time.


Nove April 5, 2011 at 10:44 pm

same case aaron LOL
some of my friends asked me too. i told them about ESE. They said ESE is a catabolism diet LOL
it’s up to them….

Elliott April 6, 2011 at 10:33 am

Great post Brad, I’m gonna share on my FB fanpage wall since I get this question all the time from my Lean Hybrid Muscle customers. Thanks!

Garret April 6, 2011 at 8:04 pm

Hey Brad,
off topic. I have been dieting down and my weight loss was steady but now I seem to be retaining a shit-load of water under my skin. I did have a day or two at slighly above maintenece calories but not enough to see a 10 pound jump in weight especially at 30 hours fasted. Any tips or do I just wait till it goest?

Calvin April 6, 2011 at 11:39 pm

Brad, I am new to your site and spent a couple of hours going through some of your archive. I really am impressed with the knowledge you’re choosing to share. Thanks for that!

I’m currently on Martin Berkan’s protocol and was wondering if you think that adding your 2x fast/week to Martin’s program would be effective?

Also for a non-fast day, can we just fill our caloric needs in 1 or 2 larger meals?

marty April 9, 2011 at 4:54 pm

google: bernar macfadden and his 1 week water only fast while walking 10 miles a day with a gain in strength and this was early 1900’s. also google dr. shelton for a real eye opening on the benefits of fasting. marty

Brad Pilon April 9, 2011 at 5:11 pm


Aware of both, thank you.


Mike April 11, 2011 at 1:10 am

Hey Brad, I too am curious to your thoughts on Garret’s question.

“Brad, I am new to your site and spent a couple of hours going through some of your archive. I really am impressed with the knowledge you’re choosing to share. Thanks for that!

I’m currently on Martin Berkan’s protocol and was wondering if you think that adding your 2x fast/week to Martin’s program would be effective?”

Brad Pilon April 11, 2011 at 10:18 am

Haven’t decided yet, I’d say do one or the other for simplicities sake, but I also see no reason why you can’t combine the two.

Mike April 11, 2011 at 12:57 pm

Thanks. What I have been doing lately is following Martin’s 16/8 protocol during the week where I am able to more easily structured. Then, after a weekend of alcohol fueled poor eating decisions, I will fast for all of sunday and not start eating monday until the hour my 8 hour eating period usually commences. I have just started experimenting with this lately, but it seems a good way to atone for lapses in dietary judgement.

Mike April 11, 2011 at 12:59 pm

able to be more easily structured*

palo April 16, 2011 at 10:42 am

Someone told me that there was a study in which a 400lb. man went on a 380 day fast – only water during this time – and lost 225 pounds with no ill effect and marginal lean mass loss.

Is this true?

Brad Pilon April 16, 2011 at 9:59 pm

If it’s the one I’m thinking of it wasn’t 380 days straight, but a flow of 2-3 weeks fasts with a couple days inbetween each. I’d have to check.

palo April 23, 2011 at 11:31 am
Bodybuilding Diets May 27, 2011 at 10:55 am

Is it bad to lose muscle when you’re on a diet? I never though this was possible though.

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