Endurance Running: How to Fuel for Maximum Energy and Performance

When we run for extended periods, our glycogen stores—the fuel stored in our muscles and liver—gradually deplete. Once these stores are too low, the body struggles to produce energy quickly, causing that "wall" or sudden exhaustion feeling, commonly called the bonk .

It's not just about feeling tired: running nutrition helps maintain blood sugar levels, prevent dehydration, reduce the risk of muscle cramps, and improve post-workout recovery. In other words, eating right while running isn't optional; it's an integral part of your strategy for running longer and better.

Carbohydrates are the most important macronutrient during endurance running. They are easily converted into glucose, the form of energy that muscles use most quickly. The amount needed depends on the duration and intensity of the effort: for runs between 1 and 2 hours, about 30–60 grams of carbohydrates per hour are recommended, while for runs longer than 2–3 hours, up to 90 grams per hour can be consumed.

The most practical forms of energy during a run are energy gels , sports drinks , easily digestible bars , or even honey . It's important to choose foods that your body can tolerate, as overly concentrated or complex carbohydrates can cause gastrointestinal upset.

Protein isn't the primary source of energy during a run, but it can play a role in longer or more intense sessions, helping reduce muscle catabolism. Small amounts of protein (such as powders dissolved in water or fortified sports drinks) can help protect muscles, especially in runs lasting over two hours.

Fats, on the other hand, become a source of energy, especially at moderate paces and during very long runs. However, while running, it's best to avoid heavy or fried fats, as they slow digestion and can cause stomach discomfort.

An often overlooked aspect is hydration. The loss of water and mineral salts through sweat affects performance, endurance, and the risk of cramps. It's advisable to drink regularly in small sips, even before feeling thirsty, and consider electrolyte supplementation (sodium, potassium, magnesium) for runs longer than an hour. Sports drinks are useful because they combine carbohydrates and mineral salts in a single solution.

Timing is crucial. For short runs (<1 hour), water or a lightly sugared drink is often sufficient. Between 1 and 2 hours, consuming carbohydrates in the form of gels or sports drinks at regular intervals helps maintain consistent energy. Beyond 2 hours, it becomes helpful to combine carbohydrates, small amounts of protein, nuts or bars, and electrolyte drinks.

It's essential to always test your nutrition during training. Never try a gel or new drink during a race without experimenting with it first: the risk of nausea or cramps is high.

• 60–90 minutes : water + energy gel halfway if necessary.

• 90–120 minutes : gels every 45 minutes + sips of sports drink.

• >2 hours : combination of gel, dried fruit or bar + sports drink + mineral salts.

Every runner has different tolerances and tastes: it's important to listen to your body and adapt your diet. Training with the same strategies you'll use in the race allows you to find the right balance between available energy and digestive comfort. Regular hydration and carbohydrates remain the key pillars, while protein and fat intake should be carefully included and customized based on the duration and intensity of your training.

With the right nutrition while running, performance improves, recovery is faster and the running experience becomes more enjoyable and sustainable.