ASK A TRAINER: 'Can You Burn Fat by Exercising on an Empty Stomach in the Morning?'

ASK A TRAINER: 'Can You Burn Fat by Exercising on an Empty Stomach in the Morning?'Hello Everyone. I've been getting a lot of questions in the inbox about food and I have to admit it's making me hungry, especially this one:

"I'm trying to lean up for summer. My buddy told me the best way to get that lean, ripped look is to workout first thing in the morning on an empty stomach. I've been doing that for two weeks and I haven't really noticed a difference. Do I just need to be patient?" -Jesse M., Yonkers, NY

In theory, the empty stomach workout theory operates under the assumption that, without access to other energy sources, your body will tap into fat stored in the body as its go-to energy source that you will burn fat without losing muscle gains.

Here's what you need to understand about how your body creates and uses energy during exercise (or even just to perform everyday movement). Your body makes a chemical called adenosine triphosphate or ATP to create the energy needed for muscular contraction. There are three energy systems your body uses to manufacture ATP. Most movements use some sort of combination of all three systems but movement during exercise usually relies a little bit more heavily on one system or another.

The first system is called ATP-CP (ATP-Creatine Phosphate). Your body uses this for powerful movements that last under ten seconds. (Interestingly, creatine supplements sold in health stores mimic this kind of energy so exercisers can trick the body into performing one last, explosive rep at a point where the body would have otherwise failed.) ATP-CP is actually already stored in muscle so fat is a non-factor with this kind of movement so fasting pre-workout isn't going to help you with explosive movement.

The second energy system is the glycolotic system. We use this system for super-intense movements lasting a few minutes. Your average weight lifting set or sprint during interval training utilizes this system. The energy source to create ATP for this particular system is primarily carbohydrates. Skipping breakfast before this type of activity is going to seriously hinder your performance.

Was your buddy talking about doing traditional cardio (low to moderate exercise performed for an extended period of time without eating)? Good luck with that. The energy system for this type of activity is called the oxidative system. The oxidative system is the most complex system for creating ATP out of all three and uses a combination of carbs, fat and protein.

Fasting before a workout is a bad idea. But won't it force the body to just use fat you ask? It may start breaking down fat stores out of desperation to get you through your (likely mediocre) workout but oxidated fatty acids not used during your workout will simply be stored in the body as fat again. Beyond that, your body will start seeking protein to assist in creating ATP and without any food in your system, it will start tapping into your muscle. If your goal is to look "ripped," you certainly don't want to be using lean muscle as an emergency energy source for your poor, starving body.

If you want to lose body fat, there aren't any new tricks. You simply cannot consume more calories than you burn. But you still need to eat because in order to get that lean, muscular look you're seeking, you're need to eat a combination of carbs, protein and some healthy fat in order to put on and maintain muscle. You are also going to want to eat small meals throughout the day because that will keep your metabolism up throughout the day. In fact, skipping breakfast is likely to slow your metabolism down.

So, Jesse, keep up the morning workouts. I admire your discipline. But, please, eat something first. And before your buddy passes on any more fitness advice, have him contact me first. Questions can be sent to or tweet me a question at @buckleybodyguru on Twitter.


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Michael Buckley Michael Buckley is an NASM certified personal trainer and fitness model. As an actor, Michael can be seen in a recurring role on the popular PBS children?s television show, ?Cyberchase FOR REAL.? Other acting experience includes roles in the feature films DELUSIONS OF GUENEVERE, HETEROSEXUALS, MONA, GYPSY 83 and national tours of GREASE and SOUTH PACIFIC. He is also a produced playwright and had two feature screenplays optioned.