When carbohydrates are ingested, they are broken down into glucose and stored in the muscles and liver as glycogen. Glucose circulates in the blood and this is also known as blood sugar. The brain and nervous system relies on glucose for energy, with the brain using a massive 70% of your available blood glucose. If your brain cells are deprived of glucose, mental power suffers and so does performance.
While protein and fat are primarily building materials, carbohydrates are unmatched at storing energy for easy and quick use when your body requires it. Carbohydrate also spares protein from being used as energy, leaving it to do its main job of building and repairing muscle.
On top of helping to build muscle, carbohydrates also help in burning fat, providing the energy source for fat oxidation (burning). Without carbohydrates, fat wouldn't burn as well.
Fuel For Sport
During exercise, your body relies on both fat stores and carbohydrate for energy. Fat is burned for fuel at about the same rate, whether it is low or high intensity. As the intensity increases so to does the body's reliance on carbohydrate for energy. The dilemma for athletes is that glucose and glycogen stores are in very limited supply. Low concentrations of carbohydrates force your muscles to rely more on fat to provide energy.
When burning fat, performance decreases significantly, forcing you to stop, and otherwise known as 'hitting the wall', 'bonking', 'seeing Elvis' or 'got nothin'. The take out message from this is also clear; if you intend exercising for more than an hour, make sure you are ingesting carbohydrate. Whether it is sports drink, energy gels or bars, you will be able to perform longer and at a higher intensity.
ATP (Adenosine Triphosphate)
Before energy can be used, it must first be transformed into a form which the body can handle easily. It is proven that ATP is formed a lot faster from carbohydrates than fat - in fact carbohydrates provide approximately twice the amount of energy than fats in the same time. During anaerobic exercise (high intensity) which uses only carbohydrates as fuel, the energy formation is almost five times faster than fats.
Immune System
Besides consuming a healthy diet and supplementing wisely, specific nutrition strategies around training are also beneficial.
When your immune system is compromised from training, you'll find elevated concentrations of stress hormones in the body. Specific nutritional strategies to boost the immune system around training sessions therefore need to be focused on reducing this stress hormone response to create less disturbance in blood immune cell counts, and lower oxidative activity.
Some of the most important nutritional strategies centre around carbohydrate intake before, during, and after training - a familiar practice for endurance athletes. Training with optimal stores of carbohydrate not only provides fuel for your workouts, but supports a strong immune system. It's known that endurance athletes who train in a carbohydrate-depleted state experience greater increases in their stress hormones. Consuming carbohydrate before, during, and after endurance exercise appears to diminish some of the immunosuppressive effects of intense training, lowers cortisol levels, leads to less changes in blood immune cell counts, lowers oxidative activity, and diminishes inflammatory response.