A Look At Intermittent Fasting And Muscle Building

L.J. Walker
Written By: L.J. Walker
September 26th, 2013
Updated: June 13th, 2020
Categories: Articles Nutrition
37.3K Reads
Two sides are at war in bodybuilding: intermittent fasting and frequent feeding. In this article LJ Walker discusses some of the possible downsides to restrictive eating.

Extremism, extremism, extremism; the wonders of the fitness industry. It never ceases to amaze me how there apparently cannot be a middle-ground when it comes to bodybuilding.

It's either high-intensity interval training (HIIT) or low-intensity, steady-state (LISS) cardio; it's either high-carb dieting or no-carb dieting; it's either over-training or under-training; last but not least, it's either 9 small meals per day or 1 gluttonous feast per day.

For now, I'd like to zone in specifically on the extreme patterns of intermittent fasting, like alternate-day fasts, and why they really aren't ideal for people looking to improve body composition, especially those looking to build muscle.

Intermittent fasting taken a bit too far

While intermittent fasting, at it's core, is certainly an intriguing feeding pattern for human health and longevity, there is a point where one can take this approach a bit too far. People will argue that meal frequency is completely "irrelevant" and believe that essentially starving their body for 24+ hours and then pigging out (e.g. alternate-day fasting) is somehow beneficial.

While acute phases (generally between 8-12 hours) of fasting do have physiological benefits, such as improved insulin sensitivity,blood glucose regulation, growth hormone output, increased adiponectin levels, and others, extreme periods of food abstinence (such as fasting one day and eating ad libitum the next day) may actually induce negative metabolic effects. [1,2,3,4]

Not to mention long-term dietary compliance and applicability don't really seem feasible for most humans on such extreme feeding patterns; who really wants to go through cycles of starving themselves for a day or two and then bingeing the next? The thing that's important to keep in mind here is that alternate-day fasting diets "work" for weight loss mainly because they inherently reduce total calorie intake.

It's not likely that an individual will be able to "make up" the extra day of not eating by pigging out on feeding days, unless they are eating some very calorie-dense foods. But again, this pattern of feeding may in fact have negative ramifications on glucose metabolism, not to mention you are greatly limiting your capacity to build muscle.


Building muscle while intermittent fasting

On that same note, the rational for alternate-day fasting while trying to build muscle seems somewhat inane given that you are essentially cutting off muscle-building pathways for an entire day and trying to make up for it the next day. This fashion of starving your body one day and then overloading it the next doesn't necessarily mean all those calories are being put to good use; in fact, your body will probably just store most of the excess energy in preparation for the next "fasting" day as opposed to using it for muscle building.

When you consider that there does indeed appear to be a "cap" to muscle protein synthesis at each feeding, it doesn't make much sense to essentially limit yourself by eating every other day. [5] A more pragmatic approach would be either pulsing your protein intake throughout the day and then eating somewhat larger, complete meals to finish off your calorie demand, or being more abbreviated with your fast/feed pattern.[6]

What I would suggest, if you plan to follow a fast-the-feed eating pattern, is to consider keeping the fasting period short enough to get the benefits of fasting, around 8-12 hours, and yet not limit your capacity to build muscle. If your goal is to build muscle, it should seem rather intuitive that extreme periods of food abstinence are probably not conducive to that process.

Just because something "works" doesn't mean it's optimal

A last thought to consider before wrapping up this article is that while many things in the health and fitness industry have some sort of merit, this doesn't entail that such methods are ideal/optimal for your goal(s). This article is not making the claim that you absolutely can't build muscle by following alternate-day fasting, but rather that it's probably not as efficient as a less restrictive feeding pattern.

The body is adaptable and can make do with what you give it, but sometimes we can push it a bit too far for our own good. Also, to reiterate, extreme patterns of feeding behavior often lack long-term compliance for a myriad of reasons. So just keep in these things in mind if you plan to follow intermittent fasting eating patterns while building some appreciable muscle.


1. Varady, K. A., Bhutani, S., Church, E. C., & Klempel, M. C. (2009). Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. The American journal of clinical nutrition,90(5), 1138-1143.

2. Higashida, K., Fujimoto, E., Higuchi, M., & Terada, S. (2013). Effects of alternate-day fasting on high-fat diet-induced insulin resistance in rat skeletal muscle. Life Sciences.

3. Smeets, A. J., & Westerterp-Plantenga, M. S. (2008). Acute effects on metabolism and appetite profile of one meal difference in the lower range of meal frequency. British Journal of Nutrition99(6), 1316.

4. Carlson, O., Martin, B., Stote, K. S., Golden, E., Maudsley, S., Najjar, S. S., ... & Mattson, M. P. (2007). Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women. Metabolism56(12), 1729-1734.

5. Areta JL, Burke LM, Ross ML, Camera DM, West DW, Broad EM, Jeacocke NA, Moore DR, Stellingwerff T, Phillips SM, Hawley JA, Coffey VG. Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. J Physiol. 2013 May 1;591(Pt 9):2319-31. doi: 10.1113/jphysiol.2012.244897. Epub 2013 Mar 4.

6. Arnal, M. A., Mosoni, L., Dardevet, D., Ribeyre, M. C., Bayle, G., Prugnaud, J., & Mirand, P. P. (2002). Pulse protein feeding pattern restores stimulation of muscle protein synthesis during the feeding period in old rats. The Journal of nutrition132(5), 1002-1008.

Posted on: Thu, 08/09/2018 - 23:18

Hi just to clarify, Which would be the best IF in reducing body body fat while gaining muscle? Would it a 12 hr fasting or the usual 16hr fasting? your thoughts & feed backs are much appreciated. Thanks much.

Posted on: Tue, 11/19/2013 - 06:45

This article should be called "The cons to Alternate day fasting" because it only speaks of fats that are for 1 or 2 days and people who pig out after words. The whole point of true intermittent fasting like eat stop eat or lean gains is to NOT pig out after your fast amd eat as you normally would not trying to make up for not eating. That would be dumb and defeat the purpose of fasting. Also a 16 hr fast which many IF'ers do is completely different than doing a 24+hr fast. I personally follow the renegade diet and have beem for 2 years. I dont think its for everyone but you can learn alot about yourself and eating habit while fasting.

Posted on: Mon, 03/30/2015 - 12:22

Brad Pilon's "Eat Stop Eat" is a great read on IF. Brad talks about 24 hour fasts, once or twice a week. He provides research and studies that show there is no muscle loss from a 24 hour fast and in fact you can build muscle while losing fast. I was following the Renegade Diet, similar to Leangains and had great results, going from 233.5 lbs at 22% bf to 212.5 lbs at 14% bf in four months. I have incorporate the 24 hour fasts twice a week to get to my goal bf of 12% bf. I did not lose any lean muscle mass while on the Renegade Diet.

Posted on: Sat, 10/12/2013 - 11:28

I would also, as done before me, point out that IF is not the same as fasting for 24+ hours. 24 hours is generally when the muscles start to deteriorate so its quite obvious not to do that if you want musclegain.
but in all honesty i believe that, say. a 2x12h fast once or twice a week on an offday wont stop your gains as long as you make sure to get your protein at the allowed hours and vitamins depending on your goals.
Now personally the only reason i do resistance training is to improve my karate training, size doesnt matter much to me (still a bonus to look good) so i might be sligthly biased in saying it doesnt stop gains.
I wont say the gains are the same but the difference will most likely be minimal, so it should really only matter to the professional bodybuilders

Article focus is too much on the bad and extreme (+24h) type of fasting and not really on the 16 or 2x12 which are also the most widespread and recommended ones.

Posted on: Tue, 10/01/2013 - 22:58

I agree with the concept of the article, but IF is being bashed based on a 24 hour fast, when most IF protocols are lower than that. As with mitymax96 above, I do leangains and stop eating at 8pm, start again at noon, a 16 hour fast. Martin from leangains even details different protocols within that 16 hour window. I workout early morning, so I follow his morning fasted workout protocol and have had great results.

Posted on: Mon, 09/30/2013 - 09:46

The author took the extreme for of IF.
There are other styles.

Try doing Leangains, I am doing that, and I like it, and I like my results.
Been doing it for almost 60 days

I will concur with the author, that when nutrition is involved, extremes are not what you want....
So I would have rather the author do an article where he did examples of both that are moderate.
Because eating 5 - 7 meals a day I don't see as extreme......I used to do this...I just got tired of it.
I don't see fasting for 16 hrs/and eating for 8 hrs as extreme either.
But doing alternate day fasts, I agree, in the long run that does not play well for someone in the gym.

Posted on: Sat, 09/28/2013 - 11:10

Yea the "pulsing" protein is a good concept that should be followed. Basically it just comes down to keeping your protein levels full to retain muscle while keeping glycogen levels low by not consuming too many carbs. I just eat protein, lots of it, all the way until my pre w/o carbs in the evening and finish with more carbs after my workout and it keeps me low bf while still putting on good muscle.

Posted on: Sat, 09/28/2013 - 06:23

Each to his own, if fasting works...keep it going, carb cycling why not I say. I try to change things around in my diet & micro nutrient intake to keep my body guessing, just like changing my work-out program. Great article, thanks!!

Posted on: Fri, 09/27/2013 - 21:46

I've had great results with intermittent fasting protocols for fat loss. First meal is typically around 5PM and the next at 8PM.

But this article makes no sense. Adding muscle equates to eating at a caloric surplus. There's no point to apply IF to this requirement since you'd run the risk of becoming full too quickly and not be able to hit your caloric/macro goals. Duh.

Posted on: Fri, 09/27/2013 - 19:22

Ive been doing intermittent fasting for dieting. It worked really well the first two weeks especially. I finally went down 4 pounds from my plateaued weight. But i am a little concerned about my body getting used to it because ive been doing it for almost 1 1/2 months..

Posted on: Fri, 09/27/2013 - 03:04

I don't do intermittent fasting, but i mainly just drink protein shakes throughout the day and eat more towards the evening, and I have great results so long as I monitor calories and micronutrients. That seems more like what you're suggesting with "pulsing" protein.

Posted on: Thu, 09/26/2013 - 18:10

Hi LJ!
Thx for the article :-)

I'm been dieting, training and competing in the IFBB (bikini) with a great coach for the past year and a half and while I was able to maintain the traditional bodybuilding/bikini diet and training for as long as I did, I just got so incredibly burnt out that I had to drop out from my last show and am now taking some time off to try to find some balance. I'm wondering.. do you think intermittent fasting has a place in a long term, healthy eating plan that focuses on aesthetics (a tight, lean look)? Or do you think it's just an extreme fad?