Carbohydrates are the best fuel for the body’s engine, more so than proteins or fats. The right carbs taken at the right time are key to good athletic performance.
Carbohydrates are the most important source of fuel in an athlete’s diet. And yet some athletes experiment with popular low-carbohydrate regimens, mistakenly believing that these diets will somehow “train” the body to burn more fat for fuel, or that carbohydrates interfere with the body’s ability to burn fat. But carbohydrates are a critically important energy source during exercise. In fact, the body cannot use fat for energy unless carbohydrate is present.
Why Carbohydrates Are So Important for Athletes
Carbohydrates are the fuel that makes the body’s engine run, and athletes need plenty of carbohydrates before, during and after exercise.
While fats can be (and are) used as a source of energy, the main function of the carbohydrates you eat is to supply energy to cells. This is particularly true for high-intensity exercise, the level at which most athletes train and compete.
The body generates energy from carbohydrates much more rapidly than it does from fat, and the brain and central nervous system rely exclusively on carbohydrate for fuel.
It’s often said that “fats burn in a carbohydrate flame” in the body. What this means is that in order for fats to be broken down completely to result in the release of energy, carbohydrate breakdown has to happen simultaneously.
This is because one of the products of carbohydrate metabolism is a substance called pyruvate. Pyruvate plays a critical role in the release of energy from fat. Without enough carbohydrate in the diet, pyruvate production drops, which impairs the release of energy from fat.
Eating enough carbohydrate is also important because it helps prevent the body from using protein for energy. While your body can use protein to supply energy, the protein you eat supports many more important functions in the body. Its primary role is to build body proteins such as muscle, bone, skin, hair, enzymes and hormones.
If you were to burn protein as an energy source, it would impact the body’s ability to perform these more important functions.
How Carbohydrates Fuel Activity
When you digest the carbs in the foods you eat, the end product enters your bloodstream in the form of glucose, or blood sugar. This is then transported to the cells to be used for energy.
Any glucose that is not used immediately can be converted into a storage form of carbohydrate called glycogen. Glycogen gets stashed away in your liver and muscles where it can be tapped into during activity.
Working muscles require a steady source of fuel, which can come from both the bloodstream and from the glycogen that is stored away. But there’s a limit to how much glycogen your body can store. If activity lasts long enough, the glycogen stores can become depleted. That’s why it’s so important to fuel properly—and regularly.
Athletes Need Carbohydrates Before, During, and After Exercise
For the average person, a well-balanced diet will usually provide enough carbohydrate to fuel daily activity. But athletes who train hard know that they need to properly fuel up before starting out, and to keep the carbs coming in during activity and to refuel properly afterwards.
If your regular workouts are strenuous and longer than an hour or so, here are some tips to keep your performance at its peak:
Before starting out, it’s a good idea to ‘top off the tank’ with some low-fat, high-carb foods to help maintain blood sugar, particularly if you exercise first thing in the morning. The best choices are foods that are easy to digest like a smoothie, a carton of yogurt or a small bowl of hot or cold cereal. Low-fat and low fiber foods are best to help avoid any stomach upset. Foods with fat and fiber delay digestion time, so they’re better eaten after exercising. If it’s hard for you to eat much in the morning, start with something small and light like a few bites of banana or a slice of toast.
During activity, specially formulated sports drinks can help keep your tank topped off. In addition to providing much-needed fluid, sports drinks are designed to provide the amount of carbohydrate recommended during activity (30-60 grams an hour for the first few hours). That’s about the amount in a liter of a typical sports drink. For longer events, some people also carry foods like low-fat cookies, sports gels, gummy candies or cereal bars for an extra boost of carbohydrate.
Refueling after a workout is critical—most of the stored glycogen will have been used up. Since your muscles are craving carbs, they’ll take them up readily and store them away for the next bout of activity. This is the time to load up on higher fiber carbs, since digestion time is no longer a concern. A dab of protein helps repair muscles, too, so ideal recovery foods include both protein and carbohydrate. It’s also important to refuel within about 30 minutes after exercise to maximize the effects of protein and carbohydrate on muscle recovery. Specialized recovery foods and beverages are convenient. Otherwise, work in plenty of healthy carbohydrates in the form of fruits, vegetables, whole grains, beans and dairy products. A sandwich on whole-grain bread, a protein shake made with milk, or a bowl of lentil soup with a piece of fruit are all great post-exercise meals.