Carbohydrates are one of the main sources of energy for exercise, but that does not mean all carbohydrates have the same effect or are used in the same way by athletes.
The choice depends on the type of exercise, intensity, duration, timing of intake, and individual tolerance. A carbohydrate source that works well before a race may not be the best option during high-intensity exercise, for example.
The Rate of Availability Matters
Different carbohydrates have different digestion and absorption characteristics. Some become available more quickly, while others are digested more slowly and may contribute to a more gradual release of energy.
For athletes, this allows the strategy to be adjusted according to the demands of the exercise. During a light, prolonged workout, a slower-digesting carbohydrate source may be well tolerated. During a high-intensity session or race, rapidly available carbohydrates may be more appropriate.
Combining Carbohydrates Can Also Make a Difference
It is not only the amount of carbohydrate that matters. Combining different types of carbohydrates can support the absorption and utilization of larger amounts during exercise.
For this reason, endurance strategies often use different carbohydrate sources, such as glucose or maltodextrin combined with fructose. This combination allows different intestinal transporters to be used and may increase the capacity to absorb and oxidize carbohydrates during exercise.
Timing Changes the Strategy
The same carbohydrate can serve a different purpose depending on when it is consumed.
Before training or a race, the strategy may prioritize energy availability and gastrointestinal tolerance. During prolonged exercise, the goal becomes providing carbohydrates to help sustain intensity and preserve performance.
After exercise, the priority is to replenish glycogen stores and provide nutrients to support recovery.
A Practical Example
Imagine two athletes competing in a four-hour cycling race.
One of them starts the race without an adequate carbohydrate strategy and relies only on the food consumed the day before. During the first few hours, they are able to maintain their pace, but as the race progresses, energy availability becomes a limiting factor and it becomes increasingly difficult to sustain power output.
The other athlete distributes carbohydrate intake throughout the race, using sources they can consume and tolerate during exercise. In this case, the goal is not simply to "eat sugar," but to provide energy in a planned way that matches the demands of the effort.
Not Every Carbohydrate Needs to Be Fast
This is also important. Slower-digesting carbohydrates are not inferior. They can be very useful in everyday meals, before certain training sessions, or when rapid energy availability is not necessary.
What changes is the context.
For athletes, there is no single carbohydrate that is ideal for every situation. There is a carbohydrate source that is better suited to a specific demand, at a specific moment, within an individualized strategy.
Carbohydrates Are a Strategy, Not Just a Quantity
Performance does not depend only on consuming carbohydrates, but on choosing sources, amounts, and timing that match the demands of the exercise.
In endurance sports, this individualization can be even more important because the ability to sustain energy for hours also depends on a strategy that is effective and well tolerated by the body.
