Carb-loading: A smart strategy for endurance athletes

Carbohydrate loading, or "carb-loading", is a nutrition strategy used by athletes to boost the body's energy reserves before long-duration, high-intensity activities. The aim is to build up glycogen—stored glucose—in the muscles and liver, which helps delay exhaustion during extended physical exertion.

Glycogen is the body's go-to fuel during endurance events. However, storage is limited and can deplete quickly. To counter this, athletes increase their carbohydrate intake while scaling back on training a few days before the event. This helps muscles stockpile more glycogen than usual, allowing for improved stamina.

Carb-loading is typically used before endurance events lasting over 90 minutes, such as marathons, triathlons, or long-distance cycling. When done correctly, it can enhance performance by a few percentage points—potentially the edge needed for a personal best.

There are two main approaches:

• A modern short-term method, which involves consuming about 10 grams of carbohydrates per kilogram of body weight daily for 2–3 days while tapering physical activity.

• A traditional six-day method, which includes an initial phase of reduced carb intake and intense training, followed by increased carbs and lighter exercise. Recent evidence suggests skipping the depletion phase still yields good results.

To avoid stomach issues, athletes are advised to eat low-fiber, easily digestible foods like pasta, white rice, or toast. Carb-loading is not necessary for short or moderate workouts but can be highly effective for longer endurance events when applied properly.