The answer to this question is going to be specifically geared for people who are running 10K or less.
First we will address the fact that you should eat something before a morning run. Your body has gone all night without any food or drink. You would not expect your car to run optimally without fuel in it, so why would you expect your body to run optimally without fuel. It is possible to run shorter distances without eating but you will be more likely to run out of glycogen stores, feel fatigued, suffer from low blood sugar, and feel nauseous if you do not eat pre- exercise. During the night, your liver glycogen stores may become depleted and then your body would struggle to maintain blood sugar levels during our workout. (Clark, 2014). Some may argue that you burn more fat while exercising on an empty stomach, but this does not equate to fat loss. To lose body fat, you need to create a calorie deficit by the end of the day and you will be much more capable of burning calories if your body is properly fueled before exercise (Clark, 2014). If your body is properly fueled, you will be able to bring a higher intensity and longer duration to your exercise.
So, how much should you eat before a morning workout?
We have determined that fueling before a morning run is essential, but you are probably wondering how much to eat because you also don’t want to deal with an upset stomach. If you plan on eating an entire breakfast before you run in the morning, make sure that you give yourself about 2-3 hours pre run to allow the food to settle, but if you find that you do not want to wake up at 5am to eat breakfast for an 8am run, then I recommend that you eat a light 200-300 calorie meal consisting mainly of carbohydrates within the hour before your run. Carbohydrates empty quicker from the stomach than do protein and fats, so it will be readily available to fuel your muscles during your run.
If you find that you cannot eat before your run in the morning, I suggest that you start out drinking some water and eating a few crackers and work your body into the routine of eating a small pre-workout meal. As you continue to add more into your pre-workout meal, your body will adjust. If you are in this category, I recommend that you also eat your breakfast before you go to bed until your body gets used to consuming a pre-workout meal. By eating a bowl of cereal, a bagel with peanut butter, or oatmeal before you go to bed, it will help boost your liver glycogen and help prevent low blood sugar the next morning (Clark, 2014).
Then poses the question, what should I eat as a pre morning run meal?
Every body is different and tolerates food differently as well. I recommend that you pick a carbohydrate based food that you know settles well. There is no magic food that everyone should eat before their morning run. I recommend that during training, you try and find what helps you perform optimally. As you experiment and discover what works best for your body, it will prepare your body for race day. Even though you may be anxious and jittery the morning of your run, your body will be able to tolerate the small meal.
Here are some ideas for you to try:
Yogurt with granola
Toast or bagel with nut butter
A couple of handfuls of light cereal
Clark, N. (5Ed.). (2014). Nancy Clark’s sports nutrition guidebook. Champaign, IL: Human