When we exercise it is important that we fuel ourselves adequately in order to minimize mental and muscular fatigue, and get the most out of our workouts. We derive our energy from the digestion of carbohydrates, protein and fat. But, which of these energy sources is more important when it comes to exercise, and what should we consume prior to working out?
Carbohydrates (sugars) are an athlete’s best friend as they are the most efficient source of immediate energy. Complex carbohydrates are broken down into smaller sugars which are absorbed and used as energy. Glucose,the simplest sugar, is absorbed directly into the blood. It is the main source of energy for our body’s cells and is the most important fuel for the creation of muscular energy.
An athlete “hits the wall” when sustained glucose delivery to working muscles fails, so its is important to understand how to avoid glucose depletion. Once all carbohydrate stores are used up, the body starts to make glucose by breaking down proteins in order to sustain energy supply to working muscles. Protein is an important building block for our muscles and it aids in tissue repair. Therefore, relying on protein as your source for energy can limit your ability to build and maintain muscle mass and can hinder recovery after exercise.
Blood sugar is the primary fuel for the brain and once it becomes low mental fatigue sets in. This contributes to muscular fatigue no matter how energy is stored in muscles. Foods containing carbohydrates have different effects on blood glucose levels. The glycemic index (GI) is a numerical value that measures how quickly a particular carbohydrate source raises blood glucose levels. Foods with a higher GI value have a rapid, short-lived rise in blood sugar, while foods with a lower GI have a slower, sustained release of glucose to the blood.
Not all carbohydrates are the same. The key to getting the most out of your workout is to understand which carbohydrates to consume and when. Carbohydrates are classified as either simple or complex, and they differ in terms of how quickly they are digested. Simple carbohydrates, in fruits and energy drinks, are absorbed and converted into energy very quickly, and are therefore a rapid source of energy. Complex carbohydrates, in whole grain bread, rice or pasta, take longer to break down and provide energy at a slower rate than do simple sugars. Starch and fibre are both considered to be complex carbohydrates, however it is important to note that fibre cannot be digested or used for energy. Generally speaking, carbohydrate foods high in fibre have a lower GI, while starchy carbohydrates have a higher GI.
So when and what should you eat prior to exercising for maximum performance? A general guide is to have a meal three-four hours prior to exercise that is mostly carbohydrates with a low GI with some protein and little fat. As you get closer to your time of exercise the size of the meal/snack should decrease and the selection should be primarily carbohydrates with minimal fat and protein so as to decrease the risk of stomach discomfort while exercising. A good rule of thumb to follow is that the closer you get to exercising, the simpler your meal should be. If you have a snack 1-2 hours before exercise this should be a light meal or snack that consists mainly of carbohydrates with a medium GI. A snack 0-1 hour before exercise should be carbohydrates only with a high GI.
To perform at your best it is essential to understand how to fuel your body. Paying attention to the foods you eat prior to exercising will help you get the most out of your workout and will help you feel comfortable and confident.