Intermittent Fasting and Muscle Gain

Posted by Jason Ferruggia

intermittent fasting and muscle gainGuest Post by Brad Pilon, author of Eat Stop Eat

Breaking it Down to Build it Up

Fundamentally this what we are doing when we are in the gym. We’re doing some damage and stressing our muscles so they can repair and come back stronger.

It reminds me of the plot of just about every Rocky movie. Rocky fights and Rocky gets his ass handed to him. Rocky makes a comeback. Rocky is bigger faster and stronger. Rocky wins.

Eye of the tiger.

I think we all kind of ‘get this’ when it comes to training, but what we might not get is the role that nutrition plays (or should play) in the breaking it down and building it up of our bodies.

Enter Autophagy

Autophagy is a process within your body that is responsible for degrading damaged and defective organelles, cell membranes and proteins. Basically it’s your body’s internal ‘maintenance system’ where it identifies and discards damaged or malfunctioning parts of a cell.

Simply put, autophagy is the clean up that needs to happen before growth and repair can occur.

The problem is it seems that both lab animals and human beings left to eat as they please do too little autophagic recycling.

The resulting accumulation of damaged cellular machinery can cause a wide range of unhealthy effects, including the accumulation of damaged mitochondria which can lead to poorly functioning muscle mass.

So the more time spent in the fed state, the less time you have to really ramp up the autophagic process within your body.

This is where fasting comes in to play. Fasting is a very potent promoter of the autophagic process.

Fasting for Muscle Mass

The strong connection between autophagy and fasting is due to the fact that the principle signal to turn up the ‘autophagy dial’ is the act of entering the fasted state.

And, if fasting is the signal to turn on autophagy, then eating is the signal to turn it off, or at the very least, turn it down.

Sadly, it doesn’t take a feast or a junk food binge to negatively affect autophagy.

Recent research published in 2010 found as little as 3 grams of the branched chain amino acid Leucine combined with 7 grams of EAA (10 grams of total amino acids) was enough to decrease autophagy markers in otherwise fasting humans.

So even a small meal in the middle of a fast may be enough to blunt the increased autophagic processes associated with fasting.

The upregulation of autophagy seems to be unique to the fasting state, as well as possibly the exercised state, and it can easily be undone by even a small ingestion of food, specifically protein / amino acids.

Autophagy and Muscle Mass

Autophagy is actually necessary to maintain muscle mass, and inhibition/alteration of autophagy can contribute to myofibril degeneration (degeneration of individual muscle fiber) and weakness in certain types of muscle disorders.

Both excess and reduced levels of autophagy are detrimental for muscle health; the former results in the loss of muscle mass, whereas the latter causes skeletal fiber degeneration and weakness.

So you wouldn’t want autophagy on all the time (fasting for weeks on end is probably not the best thing you could do for your muscle), but you do need a healthy balance of autophagy and growth for the optimal functioning of the human body (Year-long bulking cycles are probably also a bad idea).

So it’s not just your workouts that break you down and build you back up – your diet does the same thing.

The Need for Balance

By allowing for growth when we eat, and the autophagic process of repair maintenance and cleansing when we are fasting, we help restore a balance in the muscle building process, not to mention possibly playing a role in prevention of muscle loss as we age.

The key is there needs to be a balance – You can’t overeat all the time or fast all the time without expecting some sort of negative repercussions.

As with everything, there needs to be a balance – time spent training balanced with time spent resting, and time spent eating balanced with time spent fasting.

It is the optimal balance (and possibly timing) of these processes that allows for the breakdown of damaged muscle proteins, and the build up of new, bigger, healthier muscles.


To learn more about fasting, autophagy and health you can check out the all new 5th edition of Eat Stop Eat.

In the new version Brad’s included new chapters on:

  • Autophagy – More on what you read above
  • Breakfast – Good / bad, does it matter?
  • Muscle Building and Fasting – New concepts and ideas.
  • More GH Info – How fasting affects growth hormone levels
  • More info on cardio and exercise for weight loss – Cutting through some of the confusion.
  • The newest version is over 175 pages and well over 200 references. All the latest research is covered here

Brad Pilon is one of the world’s foremost advocates of intermittent fasting and has written the ultimate resource on the subject. To learn more about Brad’s unique approach to fasting check out his book by clicking HERE.

[1] A.M. Cuervo, E. Bergamini, U.T. Brunk, W. Droge, M. Ffrench, A. Terman, Autophagy and aging: the importance of maintaining ‘‘clean’’ cells, Autophagy 1 (2005) 131e140.

[1] Glynn EL, Fry CS, Drummond MJ, Timmerman KL, Dhanani S, Volpi E, Rasmussen BB. Excess leucine intake enhances muscle anabolic signaling but not net protein anabolism in young men and women. J Nutr. 2010 Nov;140(11):1970-6.

[1] Drummond DA. Mistranslation-induced protein misfolding as a dominant constraint on coding-sequence evolution. Cell. 2008; 134: 341-352

[1] Sandri M. Autophagy in health and disease. 3. Involvement of autophagy in muscle atrophy. Am J Physiol Cell Physiol 2010; 298:C1291-7

[1] Nair U, Klionsky DJ. Activation of autophagy is required for muscle homeostasis during physical exercise. Autophagy. 2011 Dec 1;7(12).