Nutrition on the Run: How to Optimize Race Day Performance

Fueling During the Half Marathon for Peak Performance

Running is one of the most popular forms of exercise, with over 275,000 road races held annually in the United States (1). Participating in an endurance event such as a half marathon requires strategic fueling to maintain energy levels, avoid fatigue, and optimize performance. Understanding what, when, and how much to consume during the race can make a significant difference in both how you feel and how you perform. Below, Kelsey Martin, CNS, LDN, at Nutrition by Kelsey with Foundations Family Medicine, LLC, shares why fueling correctly matters, which fuel options are available, and more tips for race day success. 

Kelsey Martin, CNS, LDN, shares advice on how to boost marathon performance with proper nutrition
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Why Fueling Matters

The body primarily relies on glycogen stores for energy during long runs (2,3). However, these stores are depleted after about 60-90 minutes of running, making race fueling essential to maintain performance and prevent the dreaded “bonk” (2,3).

Kelsey Martin, CNS, LDN, shares advice on how to boost marathon performance with proper nutrition

Types of Fuel

There are various fuel options available for runners, each with its benefits:

  • Energy Gels – Quick-digesting carbohydrates that provide an instant boost.
  • Chews and Gummies – Easier to consume in smaller portions and provide sustained energy.
  • Sports Drinks – Contain electrolytes and carbohydrates to support hydration and energy needs.
  • Whole Foods – Options like bananas, dates, or honey packets may be a good alternative for those who prefer natural sources.

Tip: Research what fuel sources will be available on race day and practice with them during training runs, especially if you plan to rely on these sources.

Honey Stinger
Kelsey Martin, CNS, LDN, shares advice on how to boost marathon performance with proper nutrition

Hydration considerations

Proper hydration helps prevent dehydration and offsets unwanted fatigue (4,5).

Tips:

  • Drinking water with energy gels can aid digestion and prevent stomach upset.
  • Consider less sports drink consumption if also consuming other carbohydrate sources, keep within the general guideline of 30-60 g/h (4).
  • Avoid overhydration leading to hyponatremia (low sodium levels). General guidelines recommend 6-12 oz of water or sports drink at least every 30 minutes (4).
  • Smaller frequent sips may be a way to maintain this consistency without feeling uncomfortable. 
Kelsey Martin, CNS, LDN, shares advice on how to boost marathon performance with proper nutrition

AVOIDING GI ISSUES

Many runners experience gastrointestinal (GI) discomfort during races, often due to differences in energy gels and varying amounts of macronutrients and fiber in energy bars (3).

Tips:

  • Stick to tried-and-tested fueling strategies from training.
  • Avoid high-fiber or high-fat foods before and during the race.
  • Space out fuel intake to avoid overwhelming the stomach.
Kelsey Martin, CNS, LDN, shares advice on how to boost marathon performance with proper nutrition

final tips for race day success

  • Test different fueling strategies in training and keep notes on what works best.
  • Practice with race-provided fuel and carry your own if necessary.
  • Listen to your body and adjust your plan as needed.
  • Consider race day weather – if conditions are hotter or more humid than your training, plan for additional fuel and hydration.

Proper fueling during a half marathon can help you sustain energy, avoid fatigue, and finish strong. Experiment in training, create a plan, and trust your strategy on race day!

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References

  1. Cook C, Chen G, Hager WW, Lenhart S. Optimally controlling nutrition and propulsion force in a long-distance running race. Front Nutr. 2023;10:1096194. Published 2023 May 18. doi:10.3389/fnut.2023.1096194
  2. Knuiman, P., Hopman, M.T.E. & Mensink, M. Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise. Nutr Metab (Lond) 12, 59 (2015). https://doi.org/10.1186/s12986-015-0055-
  3. Hearris MA, Hammond KM, Fell JM, Morton JP. Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Nutrients. 2018;10(3):298. Published 2018 Mar 2. doi:10.3390/nu10030298 
  4. Bytomski JR. Fueling for Performance. Sports Health. 2018;10(1):47-53. doi:10.1177/1941738117743913
  5. Judge LW, Bellar DM, Popp JK, et al. Hydration to Maximize Performance and Recovery: Knowledge, Attitudes, and Behaviors Among Collegiate Track and Field Throwers. J Hum Kinet. 2021;79:111-122. Published 2021 Jul 28. doi:10.2478/hukin-2021-0065