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