Fueling for the Finish Line

Why In-Race Nutrition Matters

For anyone participating in long-distance endurance activities like marathons, triathlons, or extended cycling events, fueling during the event—commonly referred to as in-race or intra-workout nutrition—is critical for maintaining performance and avoiding fatigue. Unlike short workouts, where stored glycogen and hydration can usually suffice, prolonged endurance events place considerable demands on the body’s energy reserves. Without proper nutrition during the race, athletes risk running out of fuel, leading to a dramatic drop in performance, commonly known as “hitting the wall” or experiencing “bonk” (Jeukendrup, 2014).

During long cardio events, the body primarily relies on glycogen (stored carbohydrates in the muscles and liver) for fuel. However, these stores are limited and can be depleted within 90 to 120 minutes of moderate to intense exercise. Once glycogen is exhausted, the body turns to fat as an energy source—but fat is metabolized more slowly, which can compromise performance. This is why consuming carbohydrates during the race helps replenish glycogen stores and maintain steady energy levels (Burke, 2015).

How In-Race Nutrition Supports Performance

In-race nutrition supports endurance performance in several important ways. First and foremost, it helps maintain blood glucose levels, which are essential for brain function and muscle activity. When glucose levels drop too low, athletes can experience dizziness, confusion, slowed reaction times, and reduced coordination—all of which increase the risk of poor performance or injury (Cermak & van Loon, 2013).

In addition to energy support, hydration and electrolyte balance play vital roles. As the body sweats, it loses fluids and electrolytes (like sodium and potassium), which are necessary for muscle function and temperature regulation. Dehydration of even 2% of body weight can impair physical and cognitive performance (Sawka et al., 2007). Therefore, a solid in-race nutrition strategy includes not only carbohydrates but also fluids and electrolytes, particularly in hot or humid conditions.

Timing is also crucial. Research suggests that consuming 30–60 grams of carbohydrates per hour during endurance events lasting longer than 90 minutes can enhance performance and delay fatigue. For ultra-endurance races, up to 90 grams per hour may be beneficial if tolerated well (Jeukendrup, 2014). Spacing intake evenly throughout the race—rather than waiting until fatigue sets in—can help keep energy levels consistent and avoid gastrointestinal discomfort.

What to Eat During a Long Race

Effective in-race nutrition doesn’t need to be complicated. The goal is to choose easy-to-digest, portable options that provide quick energy and are gentle on the stomach. While individual tolerance varies, the following types of snacks are commonly recommended:

• Dried fruits like dates, raisins, or apricots, which are rich in natural sugars and simple carbohydrates.
• Pretzels or small rice cakes, which provide a mild flavor, quick-digesting carbs, and a bit of sodium.
• Homemade energy balls or oat bites made with honey, oats, and nut butter for a mix of carbs and fat.
• Banana halves or applesauce pouches, which are easy to consume and gentle on the stomach.
• Salted boiled potatoes, a favorite among ultra-endurance athletes for their balance of carbs and sodium.

Liquids such as diluted juice or electrolyte-rich sports drinks can be helpful for those who have difficulty chewing while moving, and they support hydration alongside energy intake.

Trial and Personalization Are Key

One of the most important aspects of in-race nutrition is that it must be personalized. What works for one runner might not work for another, especially under the stress of competition. Experts recommend testing all foods and drinks during training sessions before race day to avoid unexpected gastrointestinal issues. In-race nutrition strategies should be integrated into long training runs so the body can adjust and athletes can fine-tune their timing and portions (Burke, 2015).

In-race nutrition is more than a performance booster—it’s a necessity for any athlete tackling long-duration endurance events. Proper fueling during a race helps maintain energy levels, support hydration, preserve cognitive function, and ultimately improve performance. With thoughtful planning, practice, and individualized choices, athletes can harness the power of nutrition to go farther, feel better, and finish stronger.