What Should Ultramarathon Runners Eat

Ultramarathon running demands more from your body than almost any other endurance sport. When you're covering distances beyond the marathon threshold—often through challenging terrain and unpredictable conditions—your nutritional strategy becomes as critical as your training plan. Yet many runners struggle to balance the need for sustained energy with digestive comfort, often relying on simple sugars that lead to energy crashes when consistency matters most.

The question of what ultramarathon runners should eat isn't just about race day fuelling. It encompasses your daily nutrition foundation, pre-race preparation, during-event sustenance, and recovery protocols. Research suggests that runners who develop a comprehensive approach to nutrition—one that supports both training adaptations and race-day performance—experience fewer gastrointestinal issues, maintain more stable energy levels, and recover more effectively between efforts.

The Science of Ultramarathon Nutrition

Ultramarathon running places unique metabolic demands on the body. During extended efforts lasting six hours or more, your body shifts between different energy systems, relying initially on glycogen stores before transitioning to fat oxidation as the primary fuel source. This metabolic flexibility is crucial, yet it requires proper nutritional support to function optimally. Studies indicate that ultramarathon runners may burn between 6,000 and 10,000 calories during a single event, with hydration needs varying dramatically based on conditions, pace, and individual sweat rates.

The challenge lies in consuming adequate nutrition whilst managing digestive stress. As blood flow redirects away from the gut during prolonged exercise, your ability to process and absorb nutrients diminishes. This is why many runners experience nausea, cramping, or complete appetite loss during ultras. Research suggests that training your gut to handle nutrition during long efforts—through practiced fuelling strategies in training—can significantly improve race-day tolerance. Additionally, the quality of nutrients matters enormously: whole food sources with naturally occurring compounds may support sustained energy release and reduce inflammation compared to highly processed alternatives laden with synthetic additives.

Building Your Ultramarathon Nutrition Foundation

Your daily nutrition should prioritise nutrient density, adequate protein for muscle repair (research suggests 1.4–1.8g per kilogram of body weight), sufficient carbohydrates to replenish glycogen stores, and healthy fats to support hormone production and reduce inflammation. Complex carbohydrates from whole grains, starchy vegetables, and legumes provide sustained energy without the blood sugar spikes associated with refined options. Anti-inflammatory foods—including fatty fish, leafy greens, berries, and certain mushrooms—may help manage the oxidative stress that accumulates during high training volumes.

For race-day fuelling, most ultramarathon runners benefit from consuming 200–300 calories per hour after the initial 60–90 minutes, though individual needs vary considerably. The key is practising your strategy during long training runs to identify what works for your digestive system. Many experienced ultrarunners combine liquid calories, easily digestible whole foods like bananas or cooked sweet potatoes, and strategic use of functional foods that provide sustained energy without gastrointestinal distress. Hydration should include electrolyte replacement, with sodium being particularly critical for efforts extending beyond four hours.

How Chaski Cacao Nootropic Mushroom Chocolate Helps

Chaski Cacao offers ultramarathon runners a functional food option that addresses several nutritional priorities simultaneously. Our blend combines ceremonial-grade cacao—rich in flavonoids and naturally occurring theobromine for gentle, sustained energy—with lion's mane mushroom, which research suggests may support cognitive function during the mental challenges of ultra distances. Cordyceps mushroom has been traditionally used to support oxygen utilisation and endurance capacity, whilst ginkgo biloba may enhance circulation and mental clarity when fatigue sets in. Unlike conventional energy products loaded with refined sugars and synthetic stimulants, Chaski Cacao provides functional support without the crash, making it suitable for training days when you need steady energy or as part of your pre-race nutrition strategy. The absence of added sugars also means it won't contribute to the blood glucose instability that can derail performance during long efforts.