Focus on Fitness: Fueling Tips for Running
By Kate Evans, MS, RDN
Vol. 25 No. 9 P. 50
Nutrition Strategies for 5K, 10K, Half Marathon, and Marathon Training Plans
Running is one of the most popular sports in the United States, with more than 30,000 events happening nationally each year.1 Due to the popularity of running, dietitians play a crucial role in supporting the health and performance of athletes and active individuals as they train for competitions, whether they’re new to the sport or racing at an elite level.
Key nutritional considerations for runners include adequate preworkout fluids and electrolytes to maintain hydration status and carbohydrate to provide energy for working muscles; intraworkout carbohydrate, fluid, and electrolyte intake to fuel longer duration runs; and postworkout protein and carbohydrate to support muscle recovery and replenishment of carbohydrate stores. In addition, a consistent, balanced, and nutritionally adequate meal plan between workouts serves as the foundation for a successful training regimen. Read on for some expert strategies that will enable clients to fuel and hydrate themselves adequately for their 5Ks, 10Ks, half marathons, marathons, and day-to-day training sessions.
Training and Race Day
Fueling and hydration needs vary depending on the individual athlete and the duration of a training run or race. Runners should consume 1 to 4 g carbohydrate per kg of body weight about one to four hours before competitions and training sessions lasting more than one hour to promote optimal performance. They should avoid high fiber and high fat foods preworkout due to their potential to cause gastrointestinal (GI) distress during exercise.2 Moreover, athletes should consume 30 to 60 g carbohydrate per hour of exercise lasting one to 21/2 hours and up to 90 g carbohydrate per hour of exercise lasting more than 21/2 to three hours.2 Hydration needs vary depending on sweat rate but are typically around 5 to 10 mL of fluids per kg of body weight in the two to four hours before exercise—plus 400 to 800 mL of fluids (14 to 27 oz) per hour of exercise. Exercisers should consume sports drinks or other fueling products containing sodium for exercise lasting more than two hours.2
For training sessions under one hour, clients can rely on preworkout hydration and preworkout snacks that are high in carbohydrate, low to moderate in protein, and low in fat and fiber to fuel their activity. For training sessions lasting more than one hour, advise clients to consume one sports gel (approximately 25 g carbohydrate) and about 8 oz of fluids every 20 to 40 minutes. Equivalent carbohydrate intake from sports gummies or other simple carbohydrate sources also can be used depending on the athlete’s preference. By incorporating various fueling products into their training plan, clients can determine the brands and varieties they tolerate best before race day and get a feel for their preferred fueling cadence. For clients new to intraworkout fueling, they should start small and gradually increase intraworkout carbohydrate intake throughout their training plan to help improve GI tolerance over time.
With the high level of intensity that race day brings, fueling practices become more critical. Here are some examples of how to apply fueling guidelines for four popular running distances:
• 5K: Consume a carbohydrate-rich meal and 8 to 32 oz of fluids one to four hours before the race. Intrarace fueling isn’t necessary due to the short duration.
• 10K: Consume a carbohydrate-rich meal and 8 to 32 oz of fluids one to four hours before the race, plus about 8 oz of fluids every 30 minutes during the run. For athletes who expect their race time to be more than one hour, consider adding a sports gel at the halfway point.
• Half marathon: Consume a carbohydrate-rich meal and 8 to 32 oz of fluids one to four hours before the race, plus one sports gel and about 8 oz of fluids every 20 to 40 minutes during the run. For athletes who expect their race time to be more than two hours or will race in hot conditions, consider using sodium-containing sports drinks.
• Marathon: Consume a carbohydrate-rich meal and 8 to 32 oz of fluids one to four hours before the race, plus one sports gel and about 8 oz of a carbohydrate and sodium-containing sports drink every 30 minutes during the run.
For endurance running lasting 90 minutes or longer, such as half marathons and marathons, carbohydrate loading can enhance performance and reduce the time to exhaustion.3 Carbohydrate loading is the practice of consuming larger amounts of carbohydrate leading up to a race to increase the amount of carbohydrate stored as glycogen in the muscles. Increased glycogen levels can, in turn, enhance energy levels on race day. While many athletes and active individuals don’t think about carbohydrate loading until the night before their race, current guidelines recommend consuming 10 to 12 g carbohydrate per kg of body weight for the 36 to 48 hours leading up to an endurance event.2 Strategies will vary depending on baseline carbohydrate intake, but most clients can achieve this recommendation by adding an extra serving of carbohydrate at each meal and snack for the two days leading up to their race. Clients may benefit from choosing lower-fiber carbohydrate sources, such as white rice, white pasta, and white bread, during the carbohydrate loading period since higher fiber options may tax the digestive system and increase the risk of GI distress on race day.4
Just as fueling before and during a race is important so is fueling after a race. Consuming high-quality protein with adequate carbohydrate after a training session or race is key to supporting muscle protein synthesis—the process of building and repairing muscle protein. To optimize postworkout recovery, advise clients to consume 0.25 to 0.4 g protein and 1 to 2 g carbohydrate per kg of body weight after exercise to support muscle recovery and replenish carbohydrate stored as glycogen. 5 If clients can’t consume a protein and carbohydrate-rich meal within an hour of their workout, encourage them to eat a snack that contains protein and carbohydrate to kickstart the recovery process. Potential snack ideas that provide the optimal ratio of protein and carbohydrate include chocolate milk, a peanut butter and jelly sandwich on whole wheat bread, or a fruit smoothie with protein powder. Liquid nutrition sources such as smoothies and chocolate milk can be helpful for athletes who encounter postworkout appetite suppression.
In addition, hydration is another important component of recovery nutrition. Even when athletes consume intraworkout fluids, it’s common to be at a fluid deficit after longer workouts. Prioritizing fluid intake after activity and throughout the remainder of the day, as well as consuming sodium through normal eating habits, will help restore hydration status.6 However, for athletes training in extremely hot environments or who have particularly high sweat rates, consuming a sodium-containing sports drink postworkout may be more efficient to restore large fluid deficits.
Meal Planning for Runners
In addition to achieving good hydration postworkout, consuming balanced meals throughout the day will enable runners to meet their high energy needs and get the variety of macronutrients and micronutrients that support immunity, gut health, bone health, and numerous other body systems. Meals that aren’t consumed immediately within the pre- or postworkout periods present a great opportunity for clients to include larger amounts of fiber and unsaturated fats, which have several benefits for overall health but can be difficult to digest when the GI tract is under the demands of exercise and immediate exercise recovery.
Dietitians can help simplify meal planning for clients by providing convenient options for each of the following meal components: protein, carbohydrate, fat, produce, and flavor. Ensure athletes and active individuals keep a variety of foods from each category on hand so they can build balanced and satisfying meals. Tell clients about the Athlete’s Plate, which is a validated sports nutrition education tool they can use to help with meal planning based on training intensity.7 It’s available for download at swell.uccs.edu/theathletesplate.
Building nutrition into 5K, 10K, half-marathon, and marathon training plans can elevate clients’ performance while ensuring their nutrient intake is adequate to support their activity levels and
overall health. In addition to providing guidance on weekly meal plans and general macronutrient balance, dietitians play a crucial role in educating clients on nutritional needs before, during, and after training sessions while helping to troubleshoot any nutrition-related issues leading up to race day.
— Kate Evans, MS, RDN, is a clinical dietitian at the UCLA Vatche & Tamar Manoukian Division of Digestive Diseases and a consultant dietitian at Kelly Jones Nutrition, a performance nutrition private practice that supports athletes at every level.
1. Running & jogging - statistics & facts. Statista Research Department website. https://www.statista.com/topics/1743/running-and-jogging/. Published May 12, 2023. Accessed August 12, 2023.
2. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: nutrition and athletic performance. J Acad Nutr Diet. 2016;116(3):501-528.
3. Hawley JA, Schabort EJ, Noakes TD, Dennis SC. Carbohydrate-loading and exercise performance: an update. Sports Medicine. 1997;24(2):73-81.
4. Burke LM, Jeukendrup AE, Jones AM, Mooses M. Contemporary nutrition strategies to optimize performance in distance runners and race walkers. Int J Sport Nutr Exerc Metab. 2019;29(2):117-129.
5. Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15(1):38.
6. Shirreffs SM, Sawka MN. Fluid and electrolyte needs for training, competition, and recovery. J Sports Sci. 2011;29(sup1):S39-S46.
7. Reguant-Closa A, Harris MM, Lohman TG, Meyer NL. Validation of the Athlete’s Plate nutrition educational tool: phase I. Int J Sport Nutr Exerc Metab. 2019;29(6):628-635.