Intermittent Fasting as a Tool For Muscle Gain & Fat Loss

For those seeking to lose fat and build muscle, the idea of voluntarily fasting for 16 hours, followed by an 8 hour ‘feeding’ window may seem as far from practical as possible. For those same individuals, the prospect of then training in a fasted state before waiting several hours for one’s post-workout meal would equate to the highest form of exercise sin.

However, for those with both lean muscle gains and fat-loss in mind, Intermittent Fasting may be of more interest than face value would suggest.

Figure 1. The potential results of Intermittent Fasting, personified

Debunking The Myths Surrounding Fasting:

First off, let’s allay some irrational fears . A recent study looked at the signalling pathways associated with muscle protein synthesis after a resistance training session performed in either a fasted or fed state. Participants performed a standardized training session in either a fasted state or following the ingestion of a carbohydrate-rich breakfast. Thereafter, the trainees received a solution (6ml/kg of bodyweight) comprised of carbohydrates (50g/l), protein hydrolysate (33g/l) and leucine (16.6g/l). The results indicated that resistance training while fasted stimulated the intramyocellular anabolic response to the CHO/PRO/Leucine mixture, whereas ingestion of carbohydrates prior to training actually blunted this effect.

OK, so we’ve established that the anabolic process can still be stimulated through the use of fasting; how about HGH (Human Growth Hormone)? As we know, exercise stimulates the natural production of growth hormone. This is particularly so in the case of exercise modalities that stimulate blood lactate concentration (e.g. resistance training, sprinting, etc.). It is important to note that IGF-1 as well as GH concentrations in plasma are known to be unaffected by the fasting process. Ergo, as long as an appropriate exercise-induced stimulus is present – one would not need to fear decreased growth potential. In fact, recent evidence would suggest that, on the contrary, growth hormone may be increased during 24-hour fasting periods, to the order of 1,300% and 2,000% for men and women, respectively.

Implementing a I.F Protocol & Additional Failsafe’s:

Who wants to spend 16 hours fasting in a waking-state? The chances of successfully avoiding boredom-fueled hunger pangs and elevated ghrelin levels in this manner are similar to the odds of successfully navigating an asteroid field (3,720:1). Thus, the simplest way to implement a fasting protocol would be to have your final meal of the day at approximately 8pm and fast until 12 noon the next day.

Naturally, you can begin and end the 16 hour window in accordance with your individual schedule. But, such a set-up would allow you to partake in a fasted morning training session and maximise the hormonal response from this exercise by holding off the first post-workout meal for several hours.

If you’re still worried about muscle catabolism, you can implement the additional failsafe of ingesting BCAA’s following training, coupled with EAA’s at several intervals during the fasting period to increase the markers of anabolism in skeletal muscle during and after resistance exercise. I opt for 10g EAA’s prior to training, a 5g EAA / 5g BCAA mix with 2.5g Glutamine intra-workout and 10g of BCAA’s (2:1:1 ratio) and 4g free-form Leucine post-workout.

 
References:

Karlsson, H.K., Nilsson, P.A., Nilsson, J., Chibalin, A.V., Zierath, J.R., & Blomstrand, E. (2004). Branched-chain amino acids increase p70S6k phosphorylation in human skeletal muscle after resistance exercise. Am J Physiol Endocrinol Metab, 287(1), E1-7, Epub.

Deldicque, L., De Bock, K., Maris, M., Ramaekers, M., Nielens, H., Francaux, M., & Hespel, P. (2010). Increased p70S6K phosphorylation during intake of a protein-carbohydrate drink following resistance exercise in the fasted state. Euro J App Physiol, 108(4), 791-800.

Godfrey, R.J., Whyte, G.P., Buckley, J., & Quinlivan, R. (2009). The role of lactate in teh exercise-induced human growth hormone response: Evidence from McArdle disease. Br J Sports Med, 434(7), 521-5.

Bouhlel, E., Zaouali, M., Miled, A., Tabka, Z., Bigard, X., & Shephard, R. (2008). Ramadam fasting and the GH/IGF-1 axis of trained men during submaximal exercise. Ann Nutr Metab, 52(4), 261-6.

Intermountain Medical Center (2011, May 20). Routine periodic fasting is good for your health, and your heart, study suggests. ScienceDaily. Rerieved February 5, 2013, from http://www.sciencedaily.com/releases/2011/04/110403090259.htm