Your alarm goes off at 5:00 AM (or earlier) and you have 30 mins to gulp down coffee, get your gear ready, and get out the door to swim, bike, or run. The 64 million dollar question is: should you eat and if so, what should you eat?
The quick answer is yes, you should eat something but what (and how much) you eat depends on several things.
First, think about what is going on inside that fine-tuned body of yours. If your last meal was several hours before you went to bed, chances are you have used up all the glycogen in your liver throughout the night (this is one of the ways we maintain blood sugar at night: we break down glycogen from the liver).
If this is the case and you don’t eat anything before attempting a high intensity workout (or a long workout), you will be starting this workout at a slight disadvantage because your liver glycogen is gone. This means you will only have muscle glycogen to supply your muscles with glucose (unless you want to break down muscle for amino acids to be converted to glucose or use the few free fatty acids floating around for energy). This is not good.
If you are only planning on a short, easy workout, you can easily get by with the aforementioned nutrients but if you are planning a longer, more intense workout, then keep reading.
If you decide to ingest a high carb food or beverage before your workout, these carbs will be in the bloodstream within 30 minutes and on their happy way to your fast-moving muscles. This is good.
If you decide to eat or drink something high in fat and/or protein and low in carbs, you’ll have a little energy to play with but not much.
It may help to know a few facts about digestion and “substrate utilization”:
- When food is digested, it is broken down into fat, protein, or carbohydrate. These “macronutrients” are metabolized at different rates with carbs being the fastest (especially simple sugars), and protein and fat being the slowest: they can hang out in your stomach for several hours before moving on to the small intestine. While fat and protein help you to feel fuller longer, they’re not a good choice to consume prior to high-intensity exercise or you may end up with severe GI cramps.
- Lower intensity exercise uses about 50/50 carbs and fat for energy so if you don’t eat breakfast before doing an easy workout, you probably won’t run out of glycogen because you’re not oxidizing that much carbohydrate for energy. But the total number of calories burned is much less than in high intensity activity so don’t fall for the myth that low intensity exercise is best for “fat-burning” because it is not. The percentage of fat being used for energy is higher in low intensity activity but the total number of calories burned is less than what is burned in high intensity activity.
- High intensity activity uses 80 – 100% carbohydrate for energy, most of which comes from stored glycogen. You can use up a good portion of your glycogen with 30 – 60 minutes of high intensity training. This is why its important to eat or drink something high in carbs before an intense workout. You’ll have a lot more energy if you do.
The ideal situation is to eat a high carb breakfast 2 hours prior to a hard workout (or extra long workout) but if that is not possible, get something in your tummy before heading out the door.
What should you eat or drink? Here are a few real-food suggestions for quick high-energy snacks to eat within 30 mins of exercise:
- Yogurt and juice (use 100% fruit juice for more nutrition)
- Banana and half of a small bagel
- Small muffin or lowfat cookie (Fig Newtons or homemade cookies) and juice
- Handful of Cheerios and apple juice (for you parents out there!)
- Drinkable yogurt and banana
- Sports bar and juice or grapes
These also work for pre-race “meals” when you don’t have time to eat a full breakfast. By taking in some carbs before the workout, you will prevent your blood sugar from dropping too low and delay the depletion of your muscle glycogen stores.
Lastly, prepare your food/beverage the night before so that when you wake up, all you have to do is grab and go. Make those early morning workouts worth the effort by giving your body what it needs to do the job right!