Calories are fuel for your body. Just like a car can’t go without fuel, your body can’t go without calories to burn. During exercise, the body can burn anywhere from 200-1000 calories per hour (to put it in perspective, the body burns about 140-200 simply existing). Since the body runs primarily on carbohydrates, keeping up with fueling is crucial to succeed while exercising. The body’s most efficient form of energy is glucose (it’s the simplest form of carbohydrate). When exercising at extremely high intensities your body is best at burning through glucose. When exercising at low intensities, fat, along with carbohydrates are used to fuel. This is why, if you’re looking to lose weight, exercise less intensity for longer amounts of time will help you burn fat. Going hard and fast will burn carbohydrates. When you consume carbohydrates the body stores them in the form of glycogen. Glycogen is found in the skeletal muscle as well as the liver. Very limited amounts of glycogen can be stored in the body, and since glycogen is the most important fuel during exercise, and is also quickly depleted, it is crucial to keep it topped off. When you’re running low on glycogen it is very obvious. Just like when your car runs out of gas and no matter you do, you can’t accelerate or go, the same happens with your body. You slowly cannot accelerate and then, if left too long, you’ll stop. The brain is greedy for sugar. A mental fog and decreased clarity are often the sign of a “bonk.” When you feel like this, it may be late to begin fueling. Muscle fatigue and decreased performance are also side effects. Overtraining without properly fueling and recovering can lead to long term glycogen depletion. FUELING FOR YOUR WORKOUT: Along with hydration, carbohydrate consumption during exercise is the primary nutrition goal. During high-intensity or race pace exercise, many guidelines suggest ingesting 30-60g of carbs per hour. When fueling mixing simple and complex carbohydrates help slow down the rate of absorption into your body. When you use complex carbohydrates, the glucose will not all hit your bloodstream at once, and instead slowly is absorbed by the muscles and liver to become a longer lasting energy source. For longer duration exercise that’s at a lower intensity, more calorie and/or nutrient dense bars should be eaten. Bars that have a buffer of fat or protein will help release energy to your body over a longer period of time. Some foods that are great for longer rides are Rip Van Wafels, Enduro Bites, Pocket Fuel and Taos Mountain Energy Bars. For short workouts, you should use gels and chews, primarily made up of simple sugars. The simple sugars Glucose and Fructose are quickly absorbed into the body, delivering quick energy to your muscles. However they do not last, and once you begin consuming sugar during a workout, you may find that you need to continue fueling your body with sugar at regular intervals to avoid a bonk. Our favorite gels and chews are: ProBar Bolt, PowerBar Blasts, Clif Bloks, Clif Shots and Gu Roctane. Big blocks of training or racing require more fuel. Being properly nourished with carbohydrates and calories before a workout, and going into each day of training makes sure that the engine is good to go when it really counts. It’s never good to be playing catchup. Be sure to experiment with different types of nutrition products during training instead of competition. Figure out what works best for you, and take that knowledge to the races.