Understanding Carbohydrates for Sports Performance 2025

Carbohydrates are one of the most debated macronutrients in sports nutrition. Often misunderstood, they play a crucial role in energy production, endurance, and recovery for athletes. Whether you’re a long-distance runner, a sprinter, or a strength athlete, optimising carbohydrate intake can enhance performance, delay fatigue, and speed up recovery.

This article explores our understanding carbohydrates for sports performance, their function in the body, the best sources, and how athletes can tailor their intake for optimal performance. With evidence-backed insights, we’ll break down how to effectively use carbohydrates to fuel your training and competition.

What Are Carbohydrates?

Carbohydrates are the body’s primary energy source, especially during high-intensity exercise. When consumed, they are broken down into glucose, which is either used immediately for energy or stored as glycogen in muscles and the liver for future use (Jeukendrup, 2014).

There are three main types of carbohydrates:

Simple carbohydrates – Found in sugars like glucose, fructose, and sucrose, which provide quick energy.
Complex carbohydrates – Found in whole grains, vegetables, and legumes, which release energy more slowly due to their fibre content.
Fibre – Important for digestion and gut health but does not contribute directly to energy production.

The type and timing of carbohydrate intake significantly impact sports performance and recovery.

Understanding Carbohydrates for Sports Performance: Bowl of pasta noodles, chicken with a leaf on top. — Photo by engin akyurt on Unsplash

How Carbohydrates Impact Sports Performance

Carbohydrates play a direct role in endurance, strength, and recovery. During exercise, your muscles rely on stored glycogen for fuel. Studies show that depleting glycogen stores leads to a significant decline in performance, known as “hitting the wall” (Cermak & van Loon, 2013).

Glycogen as a Fuel Source

Muscle glycogen is the primary energy reserve during prolonged and intense exercise. The body has limited glycogen stores, typically 400-600g, which can sustain about 90–120 minutes of continuous effort before depletion occurs (Burke et al., 2011). When glycogen levels run low, fatigue sets in, and performance declines.

Athletes who optimise glycogen storage through carbohydrate loading and maintain levels with proper intake during exercise perform significantly better than those who do not (Hawley & Leckey, 2015).

Carbohydrate Timing for Athletes

Timing carbohydrate intake correctly can enhance training adaptations, energy availability, and recovery. Understanding when and how much to consume is crucial.

Pre-Exercise Carbohydrate Intake

Consuming carbohydrates before training or competition ensures that glycogen stores are full and provides readily available energy. The ideal pre-exercise meal should be rich in complex carbohydrates, moderate in protein, and low in fat and fibre to prevent digestive issues (Burke et al., 2011).

Examples of good pre-exercise meals:

Oats with banana and honey
Wholegrain toast with peanut butter
Rice with lean protein and vegetables

Carbohydrate Intake During Exercise

For endurance sports lasting longer than 60 minutes, consuming 30-60g of carbohydrates per hour helps sustain energy levels and delay fatigue (Stellingwerff & Cox, 2014).

Common carbohydrate sources during exercise include:

Energy gels and sports drinks
Bananas and dried fruit
Rice cakes or homemade energy bars

Post-Exercise Recovery

After intense exercise, restoring glycogen stores is a priority. The optimal post-exercise recovery meal should contain 1.0-1.2g of carbohydrates per kg of body weight within 30-60 minutes after finishing (Ivy et al., 1988). Pairing carbohydrates with protein (20-25g) enhances muscle repair and glycogen synthesis.

Best post-exercise recovery meals:

A protein smoothie with banana and oats
Wholegrain pasta with chicken and vegetables
Greek yoghurt with honey and granola

The Role of Carbohydrate Loading

Carbohydrate loading is a strategy used by endurance athletes to maximise glycogen storage before competition. This involves increasing carbohydrate intake 3-4 days before an event while tapering training volume (Burke et al., 2011).

Benefits of carbohydrate loading:

Increases glycogen stores by 50-100%
Delays fatigue and sustains performance in endurance events
Enhances time to exhaustion and overall race-day energy availability

Foods rich in complex carbohydrates such as pasta, rice, oats, and potatoes should form the base of a carbohydrate-loading strategy.

Low-Carb vs. High-Carb Diets for Athletes

There is ongoing debate about low-carbohydrate (ketogenic) vs. high-carbohydrate diets in sports. While low-carb diets have gained popularity, evidence overwhelmingly supports high-carbohydrate diets for endurance and high-intensity athletes (Burke et al., 2021).

When Low-Carb Diets May Work

Some research suggests that low-carb, high-fat (LCHF) diets can improve fat oxidation and endurance in low-intensity activities (Volek et al., 2016). However, these diets have shown to impair high-intensity performance due to reduced glycogen availability.

For most athletes, maintaining a balanced carbohydrate intake based on training demands is the best approach.