Endurance running presents significant physiological demands, requiring athletes to implement carefully structured dietary strategies to enhance performance, support recovery and maintain overall health.
Recent research has underscored the critical roles of macronutrients, micronutrients, and hydration in meeting the metabolic and structural needs of endurance athletes. The following analysis synthesises current scientific findings to provide an evidence-based approach to optimal dietary practices for runners.
Macronutrient Considerations
Carbohydrates: Primary Energy Substrate: Carbohydrates serve as the primary energy source for endurance activities due to their efficient oxidation rates and ability to rapidly generate adenosine triphosphate (ATP), the body’s energy currency.
Glycogen, stored in muscles and the liver, is the most readily available energy reserve, and its depletion is closely linked to fatigue and diminished performance.
Endurance athletes are advised to consume 40%-70% of their daily caloric intake from carbohydrates to maintain energy stores. Carbohydrate loading 36-48 hours before competition has been shown to significantly increase muscle glycogen stores, enhancing endurance capacity.
Low-glycaemic index (GI) carbohydrates such as whole grains, fruits, and starchy vegetables are ideal for sustained energy release.
Protein: Muscle Recovery and Adaptation: While carbs and fats are primary fuel sources, protein is essential for muscle repair, mitochondrial biogenesis, and overall recovery.
Athletes should aim for 1.2-1.4g of protein per kilogram of body weight per day, with protein evenly distributed across meals to maximise muscle protein synthesis. Ultra endurance athletes may require up to 1.8g per kilogram to support increased muscle damage associated with prolonged events.
According to The Journal of Physiology, consuming protein post-exercise enhances muscle recovery and promotes training adaptations in endurance athletes.
Fats: Endurance Fuel and Anti-Inflammatory Support: Fat oxidation becomes a predominant energy source during prolonged, moderate-intensity running. Endurance-trained athletes develop enhanced fat metabolism, preserving glycogen stores and improving endurance performance.
Athletes should consume 15–35% of their daily calories from healthy fats to promote cardiovascular health and reduce systemic inflammation.
Omega-3 fatty acids help reduce exercise-induced inflammation and support muscle recovery.
Key Micronutrients for Runners
Iron: Oxygen Transport and Energy Metabolism: Iron is vital for oxygen transport, as it is a key component of haemoglobin and myoglobin, which facilitate oxygen binding in blood and muscle tissues.
Runners, particularly female athletes, face an increased risk of iron deficiency due to factors such as haemolysis, sweat losses, and gastrointestinal bleeding.
Men require about 8mg of iron daily, while women need 18mg. Haem iron from animal sources is more bioavailable than non-haem iron from plant-based foods, though vitamin C enhances non-haem iron absorption.
The Journal of Sports Sciences reports that iron deficiency negatively impacts endurance performance and increases fatigue risk.
Calcium and Vitamin D: Bone Health and Injury Prevention: The high-impact nature of running increases the risk of stress fractures and bone density loss, making calcium and vitamin D essential for maintaining skeletal health.
Adults require about 1000mg of calcium daily. Vitamin D is primarily obtained from sunlight exposure, fatty fish, and egg yolks, and Medicine & Science in Sports & Exercise highlights that adequate calcium and vitamin D intake reduces stress fracture risk in endurance athletes.
Hydration Strategies for Runners: Pre-exercise hydration is crucial, with recommendations that runners consume 500ml of water 2–3 hours before exercise. During exercise, runners should aim to replace lost fluids at a rate of 150–250ml every 15–20 minutes. After exercise, rehydration should focus on replacing fluid losses with water or electrolyte solutions to restore balance.
Endurance runners require a meticulously planned diet to support performance, recovery, and overall health so by focusing on an optimal balance of carbohydrates, proteins, fats, vitamins, and minerals, runners can improve their training outcomes and optimise their competition performance.
