Carbohydrates are often misunderstood in the world of nutrition. While some people try to reduce or eliminate them for weight control, endurance athletes embrace them—and for good reason.

Carbohydrates are the body's preferred and most efficient energy source, especially for high-intensity and long-duration activities like running, cycling, and swimming.

When athletes compete in events lasting more than 90 minutes, carbs help maintain stamina, focus, and muscle function.

Glycogen: The Body's Energy Storage

When we consume carbohydrate-rich foods such as rice, pasta, or fruit, our body stores part of that energy in the form of glycogen—mainly in the liver and muscles. Glycogen is easily and quickly converted into glucose, the fuel your muscles use during extended effort.

According to sports medicine research, having adequate glycogen stores is directly tied to performance. When glycogen is depleted, so is your energy—and that's when fatigue sets in.

Timing Matters: Before, During, and After

Carbohydrate needs vary depending on the timing of intake.

- Before an event, consuming complex carbohydrates 2–3 hours prior (like oatmeal, bananas, or sweet potatoes) ensures your glycogen stores are topped off.

- During prolonged exercise, particularly beyond 60–90 minutes, endurance athletes benefit from 30–60 grams of simple carbs per hour. These may come from energy gels, sports drinks, or fruit.

- After training, carbohydrate intake is critical for recovery. Within the first 30 minutes post-workout, combining carbs with a protein source helps replenish glycogen and repair muscle.

Carb Loading: Useful or Outdated?

"Carbohydrate loading" is a strategy that involves increasing carbohydrate intake several days before a long race. This technique, when paired with a slight taper in exercise, increases muscle glycogen reserves.

Although traditional carb loading isn't necessary for every endurance event, it can be useful before marathons, triathlons, or multi-hour bike rides. However, modern approaches suggest a balanced carb increase instead of the old-school "stuff-yourself" method.

Types of Carbohydrates: Simple vs. Complex

Understanding the difference between simple and complex carbohydrates can guide smarter fueling strategies.

• Simple carbs (such as glucose or fruit juice) digest quickly and are ideal during activity when fast energy is needed.

• Complex carbs (like whole grains and legumes) break down slowly, providing a more sustained energy release—better for meals before competition or long training sessions.

The Right Amount: How Much Do You Need?

Carbohydrate needs depend on the duration and intensity of activity. The International Society of Sports Nutrition recommends the following daily intake:

• 3–5 g per kg of body weight for low-intensity or recreational athletes.

• 5–7 g/kg for moderate endurance training.

• 7–10 g/kg for high-volume endurance training or competition.

A 70-kg marathon runner, for instance, may need 490–700 grams of carbohydrates daily during peak training weeks.

Signs You're Not Getting Enough

If you constantly feel tired, experience mood swings during workouts, or hit a "wall" early in your training, inadequate carbohydrate intake may be the reason. Low-carb athletes might also see reduced motivation, delayed recovery, and poor performance in long-duration events.

Listening to your body is key—energy dips are often signals to adjust your fueling strategy.

Hydration and Electrolytes Matter Too

Carbohydrate metabolism is closely linked to hydration. Glycogen binds with water, and when it's used for energy, the body loses both fuel and fluid. That's why sports drinks often combine carbohydrates with sodium and potassium. For endurance athletes, this pairing supports muscle contraction, energy delivery, and hydration in one go.

Common Misconceptions About Carbs

Many people associate carbohydrates with unhealthy weight gain or energy crashes. However, these effects are often linked to poor carb choices (like processed sugar or pastries) rather than whole, nutrient-rich options. Athletes need not fear carbohydrates—in fact, when used correctly, they are one of the most powerful tools for endurance.

Expert Insight: What the Science Says

Dr. Louise Burke, a leading sports nutritionist, notes that carbohydrates are "absolutely essential for peak athletic performance." In a study published in the Journal of Applied Physiology, athletes who followed a high-carbohydrate diet performed significantly better in endurance trials compared to those on a low-carb regimen.

Scientific consensus supports the importance of carbs in both training and competition.

Personalize Your Strategy

There is no one-size-fits-all nutrition plan. Some athletes perform better on higher or lower carb intakes depending on genetics, training style, and preferences. It's essential to experiment during training, not competition, to discover what works best for you.

A sports dietitian can also help design a personalized nutrition plan based on your body type and goals.

Final Thoughts: Don't Fear the Fuel

Carbohydrates are more than just calories—they're fuel, recovery tools, and performance enhancers. If you're serious about endurance sports, understanding how to properly use carbohydrates can make the difference between a sluggish finish and a strong personal best. It is important to evaluate and adjust your fueling strategy regularly.

If you have an upcoming race or want to refine your nutrition plan, let me know—I'd be happy to help tailor your strategy!