‘Carb-loading’ is a myth. But how much carbohydrate do athletes really need?

Endurance runners often use carbohydrate gels to 'fuel' their muscles. Real Sports Photos/Shutterstock

For many years, sports nutrition was rooted in a simple metaphor: the body is an engine, glycogen (the body’s quick-release carbohydrate reserve) is its fuel, and fatigue occurs when the tank runs low.

Under this logic, nutrition strategy seemed quite obvious: eat lots of carbohydrates, fill the tank, and if possible, keep topping it up while exercising. More carbs = better performance.