There are lots of opinions and studies running around out there about whether or not it’s beneficial to eat prior to exercising. Some people claim that they run faster/better/with fewer tummy issues on an empty stomach. Others swear they have an iron stomach and can eat an egg and cheese sandwich from the deli right before a big race. (Eww)
Here are a couple of things just for you to know:
- When you exercise for long periods of time, you use different forms of energy. For the first 30-35 minutes, it’s usually that you’re using readily available glycogen from recent ingestion. Beyond that, you are using stored energy in stored in your fat cells. When that runs out your body will go anywhere for the energy, including your muscles and organs.
- During exercise, digestion is basically halted. Blood is pumped to other, more active areas of your body (muscles, heart, lungs) and away from your stomach when your heart rate is elevated for any reason at all. It’s part of the sympathetic/parasympathetic nervous system dynamic. That means, while you’re exercising, whatever is in your stomach will probably not go much further than your stomach until your heart rate comes down and you “rest and digest”.
- Having low blood sugar can make you feel dizzy, nauseous and weak. Three things you definitely don’t want to feel when you’re trying to have an awesome workout. Generally, things like carbohydrates and simple sugars absorb quickest into the blood stream and can raise blood sugar counts back to normal fairly quickly.
Knowing when and what to eat before a workout is a very personal, very individual thing. I mean, you’re getting this from someone with a digestive diseases so, I get it. However, I have had many an athlete show up for a workout with me only to have them bonk midway through because they hadn’t eaten anything all day/since breakfast/since lunch. The remedy usually involves me running out the door for crackers and apple juice so that they don’t pass out or vomit (hasn’t happened yet!). It also means they missed a perfectly good workout because they didn’t think far enough ahead to fuel up for it.
Running on empty is not a good idea. Your body is a machine and you cannot control where it will take fuel in the absence of energy from food. If you want your body to perform at 100% you have to do your part, too. I get it. It’s early in the morning and you have barely 10 minutes to wake up, get dressed and run out the door. I get it.
Have a quick slice of toast. Have half a Luna Bar. Take a Gu, Shot Bloks or Sport Beans with you. Swig a Gatorade or a Vitamin Water. These little gems are exactly formulated to be absorbed into your blood stream without having to go through total digestion in your stomach. Actually, they’re pretty cool. The absorption starts in your mouth where all those capillary beds are under your tongue and stuff…anyway. Physiology lesson another day. Point is, you have options so that you’re not running on empty.
And those of you who are chowing down a burger and then going out for a run 15 minutes later. Please. Simple science will tell you that burger is going nowhere while you are getting your workout on. And who wants to run with a quarter-pounder in their gut? Yuck.
So, knowledge is power. Use it. And don’t get caught running on empty!
Now go out and run!