Fasting: Pros & Cons

Age old argument here…should you train fasted or fueled? Is fasting the right way to go when prepping for a big event? I personally have always trained fasted.  I have found that if I eat too much prior to a hard training or run, I end up with stomach issues.  Hydration has always been more of a factor to me.  I’m not saying that is right, but I have found that this has made me more comfortable and less vomity (technical term).  You will find people on both sides of this coin arguing, to their success, the benefits of both philosophies. 


Part of the workout routine I currently utilize has me fasting prior to training from food but not necessarily low caloric liquids or pre-workout energy mixes.  I use Muscletech’s  Neurocore and then within the hour of finishing my workout get a healthy meal of protein and carbohydrates.  Much of the rest of my meal for the day consists of high protein and relatively low carbs.  My endomorphic body composition (yes my own bad luck) does not allow me to tolerate carbs well (think of the Stay-Puff Marshmallow Man from Ghostbusters).  I have not run into energy issues during my training but I will say I have had issues with cramping on long runs.  Hydration seemed to take care of most of that…and better shoes.

In an online article by Nick English called Exercising on an Empty Stomach: The Surprising Benefits, English points out that-

“An empty stomach triggers a cascade of hormonal changes throughout the body that are conducive to both building muscle and burning fat.”

My personal opinion is that everybody needs to experiment with the processes that work for themselves.  Endurance athletes will tell you one thing, strength athletes will advise something else, and your general fitness/nutrition experts may have another opinion.  I mix and match different thoughts to keep my body guessing and to fine tune what works for me.  Depending on my goals it may change.  The most important thing I have learned, and I take this from a friend of mine on the Southern Indiana Triathlon Team, Beth Gabhart is…listen to your body.  It will tell you what you need to know.  Now she is an advocate of fueling before training.  She is an accomplished triathlete, nurse, and nutritionist.  So her advice is not taken lightly.  She knows her stuff. 


The real question is, does fasting during your training allow you to burn more fat than training fueled.  And I find most discussions tend to circle back around to fat burning.  Again studies show evidence that both theories hold true.

Another online article by Brad Shoenfeld called The myth of cardio before breakfast debunked talks about why training fasted does not produce more fat burning.  I didn’t find the article to necessarily debunk this fact but rather to tell you that it “depends” on the type and intensity of the training…and then what works for you.  Shoenfeld states:

“Summing up, the strategy to perform cardio on an empty stomach is misguided, particularly for physique athletes.  At best, the effects on body composition won’t be any better than if you trained in a fed state; at worst, you’ll lose muscle and reduce total fat loss. So if you should eat…what should you eat prior to cardio?  The answer depends on several factors, including the duration and intensity of training, the timing of previous meals before the cardio session, and individual genetics.”

It is also important to note he speaks of “cardio” prior to breakfast, not necessarily other types of training.  So in a nut shell I believe it comes down to what you find works for you.  And any trainer will tell you that everybody is different and you have to modify and tweak any plan to fit your body. 

I do know that in all of my high intensity training workouts where I have been fasting while training, I have not felt a loss in energy when I prepare the day or night before with my nutrition.  So take that for what it’s worth.  What I have found, and this comes from Beth Gabhart also, is you have about 90 minutes of electrolytes in your body and you need to actively replace those stores throughout your training or you will hit a wall.  I have hit that wall running at almost exactly 90 minutes.  It took me a lot of tweaking to find the hydration solution to that issue.  So my one suggestion is that if your training is really going to go beyond an hour you need to prepare and be ready to give your body what it needs to get past that point.  Listen to your body.


Previously Fat Guy

Free Shipping For Orders Over $50! Dismiss