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Fact or Fiction – You Shouldn’t Eat Before Working Out


Going along with my first post on Lean It Up about squat depth, we’ve decided to start a weekly column — entitled Fact or Fiction — in which I will be discussing commonly held nutrition/fitness beliefs and whether or not they actually hold any merit. While I have no certifications or medical background, I have personally tried plenty of different diet strategies and workout routines over the years, and I am also fairly decent at digging up information and presenting it in a no-bullshit manner (everything is also fact-checked by Bryan). Therefore, while I would love to explain the science behind a lot of this stuff, I’m not in any position to do that. What I WILL do is provide some advice based on research studies and experiments, as well as my own personal experience, and you can take it or leave it for what it is.

This week’s topic is one that I was hesitant to talk about, as I didn’t actually think people still believed this kind of thing until it was brought to my attention that this wasn’t the case. Apparently people still walk around telling others, as well as believing themselves, that you shouldn’t eat any food before exercising. I just want to say upfront right now that this is quite possibly one of the dumbest things I’ve ever heard, and it makes me furious when people who don’t know any better follow such stupid advice.

I’ve heard many personal trainers and self-proclaimed “experts” argue that people should train on an empty stomach, given that by eating (particularly carbohydrates) before working out, one will “waste” his/her workout by just burning through the recently consumed food and not tapping into any fat stores.  Thus, they argue that no fat will be burned during exercise (which people seem to consider as the absolute worst thing in the world), and that conversely, by training fasted they will experience enhanced fat burning effects.  Let me explain why this is just a whole load of crap.

fitness myths, fitness questions

Reason 1.

You may burn more fat during your workout if you don’t eat beforehand, but you can’t simply look at that small window as the only time of day that matters. The last time I checked, there were still another 22-23 hours in the day (assuming your workout lasts for 1-2 hours) in which your body functions, grows, changes, etc.  Given that your body doesn’t produce noticeable results after just one workout, you have to look at things from a longer-term perspective, such as over the course of days, weeks, and even months.

And that’s where the zinger kicks in: a study by Brad Schoenfeld, MS, CSCS in the Strength & Conditioning Journal of February 2011 showed that at the end of the day, your body burns the same amount of fat regardless of whether or not you eat before working out. The reason for this, interestingly, is because your body ultimately makes adjustments and evens things out over longer periods of time. If you burn more fat during your workout, then you’ll burn more carbs throughout the rest of the day. And if you burn more carbs during your workout, then you will burn more fat throughout the rest of the day. You see, your body is much, much smarter than you…and if it could, it would probably laugh at your futile efforts to try and trick it.1

 

Reason 2.

Even though I said in point #1 that you may burn more fat during your workout by not eating beforehand, research has shown that this is only true under certain conditions, such as in workouts exceeding specific lengths of time. In many cases, pre-workout starvation may not even give you that one benefit you thought it had. What a tease.

 

Reason 3.

You’re far more prone to losing muscle by not eating a meal before working out, particularly during aerobic cardio activity. By not getting a good serving of carbohydrates and protein/BCAAs (branched-chain amino acids) before exercising, your body will burn right through the limited glycogen stores (think stored energy within your muscles) in your system.  Without any other source of energy, it may start tapping into and breaking down hard-earned muscle for fuel. While I understand that some people don’t care as much about this, I personally do…and I view this as a serious downside to why one shouldn’t train without eating first.

So now that you know why it isn’t smart to train fasted, let’s take a look at why it is smart to train after eating a meal.

Right off the bat, just think about this from a real simple level first, and I’ll use an analogy I’ve heard many people use that I actually really like. Think of your body like a car. In order for your car to run, you need to put fuel in it, right? If you want your body to function properly and at its highest level, it only makes perfect sense that you “fill up the tank” ahead of time by eating a solid meal, and a high quality meal at that (think various grades of gas).

There are countless studies that have proven MAJOR training performance increases when carbohydrates are consumed beforehand. One particular study conducted at the Mississippi State University and published in the Journal of Strength and Conditioning showed that in exercise involving repeated static contractions of the quadriceps, participants who consumed carbohydrates before and during exercise experienced a ~52% higher force output and ~81% longer time to exhaustion than those who were given a placebo. Another study, conducted at the Exercise Physiology Laboratory of Ohio State University and published in the Journal of Applied Physiology, found that in well-trained cyclists, total work produced was 19-46% higher and time to exhaustion was 18-44% higherwhen carbohydrates were consumed before and/or during exercise compared to when none were consumed at all.23

But why is this important? If you’re not being judged on your exercise or in a competition against others, why do you care about maximizing performance in your workouts? The reason is this: by having more energy and performing at a higher level, not only will you feel better during your workout, but you’ll also be likely to burn more calories during exercise. This ends up having a compound effect, as higher intensity and more calories burned during exercise will give an increased boost to your metabolism, increasing the calories your body burns throughout the remainder of the day. On the other hand, if your goal is to build muscle, the argument is substantially the same: if your body isn’t fueled up properly, your workouts will suffer and you likely won’t see much growth/progress.  So eat up before you head to the gym!

MMM, DELICIOUS!

In terms of what to eat, I’ve personally had great experience with complex carbohydrates, as they provide a gradual and steady release of energy that lasts through a large portion of my workout, and I’ll usually shoot to eat this meal about 1-2 hours before exercising in order to give it proper time to digest in my system before I start any movement. You can choose from plenty of different carb sources and I even suggest experimenting with different combinations to see what works best for you, but I like to go with a solid bowl of oatmeal and some sort of fruit (usually berries or grapes).  I also recommend getting in a good source of protein/BCAAs in order to further buffer against any potential muscle breakdown during your workout.

So try out different carb/protein sources and have some fun with it, but just remember to get that pre-workout meal into your body in order to maximize your training and results.  And the next time someone advises you to do otherwise, feel free to offer them a slice of bread…they could probably use it.

 



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References, Notes, Links

  1. Does Cardio After an Overnight Fast Maximize Fat Loss? Schoenfeld, Brad MS, CSCS. Strength & Conditioning Journal: February 2011 – Volume 33 – Issue 1 – pp 23-25. []
  2. Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation. Wax B, Brown SP, Webb HE, Kavazis AN. J Strength Cond Res. 2012 Jun;26(6):1717-23. []
  3. Carbohydrate feedings before, during, or in combination improve cycling endurance performance. Wright DA, Sherman WM, Dernbach AR. J Appl Physiol. 1991 Sep;71(3):1082-8. []