Amy Stephens
MS, RDN, CSSD, CDCES
Licensed dietitian
specializing in sports nutrition
and eating disorders
Nutrition for a Half Marathon: Fueling for Performance
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By Amy Stephens RDN CSSD
Whether it’s your first half marathon or your 10th: Whether you’re aiming for a PR or running for fun, proper nutrition is key to sustaining energy, optimizing performance, and ensuring good recovery. This guide covers everything you need to know about fueling before, during, and after your race, along with common mistakes to avoid. While general guidelines can help all runners, fueling is individual, and what works for one person might not work for you. It’s important to experiment to see what feels best for you.
Most race plans start about 12 weeks out, allowing time for your body to adapt to increased mileage. Use your training period to practice fueling strategies and determine what works best for you.
During exercise, your body relies on glycogen, the stored form of carbohydrate, as a primary fuel source. After glycogen stores are depleted, your body requires additional carbohydrate fuel from gels. Here’s why gels are essential:
Fueling for Long Runs: overview
Early in training, test different foods to find out what your body tolerates best. Use this time in practice to determine both which foods feel best for race day and when to consume them to avoid stomach discomfort. More time before a run will allow your body to digest more food, but easily digestible carbs low in fat and fiber will provide the best fuel with the lowest risk of discomfort. If you are hesitant to fuel pre-run, speak with a sports dietitian for a customized approach. You can learn strategies to improve your gastrointestinal (GI) tolerance.
- Shorter runs (<80 min) fueling is optional. That means, if you feel hungry, it’s important to listen to your body and eat before you run.
- Longer runs (>80 min) will benefit from added carbohydrates before and during to keep up energy levels.
Best Foods to Eat Before a Run
3-4 hours before: Meal – Bagel with peanut butter, honey, banana, and fluids.
1-2 hours before: Snack – Pretzels with peanut butter or toast with honey and fluids.
<30 minutes before: Quick carbs – Gels, Honey Stinger Waffle, or sports drinks.
Fueling During a Run
- Runs <80 min: Fueling is optional.
- Runs >80 min: Eat a carbohydrate rich breakfast (toast with peanut butter or jelly) and consume 30-60g of carbohydrates per hour (1-2 gels or equivalent). Check out this blog post for a comparison of the different gels.
- Start fueling early (around 30 min in) to prevent hitting the wall. Don’t wait until you feel fatigue; fuel early.
- Real food requires more digestion and can increase GI distress.
Hydration
- According to the American College of Sports Medicine (ACSM), drink 16-20 oz of fluids about two hours before and 5-12 oz of fluid every 15-20 minutes. This amount changes based on individual sweat rate, weather, and intensity.
- An individualized hydration plan is helpful to determine how much fluid to drink.
- Perform a sweat test (weigh before and after a one-hour run) to estimate fluid needs. Gatorade sweat loss calculator.
- Losing 2% of body weight from sweat affects performance.
- Aim for half your body weight (lbs) in oz of fluid per day (e.g., a 150-lb runner needs 75 oz minimum).
- Include electrolytes (Nuun, Salt sticks, gels with electrolytes such as Neversecond). The more you sweat, the more electrolytes you need to replace. Start with 300 mg sodium per hour and adjust.
Caffeine & Performance
Caffeine can improve sports performance by increasing alertness and reducing fatigue. Some studies have also shown that caffeine can increase fat utilization and spare glycogen during endurance events.
- Timing: Take one hour before a competition to optimize performance.
- Dosage: 3-6 mg/kilogram, which is about 200 mg (tall coffee from Starbucks) for most individuals.
- Caution: Too much caffeine can cause jitters, shakiness, and an upset stomach.
- Test out caffeine before race day to see how it affects your body. Even if you consume caffeine in your daily life, caffeine may feel different in your system during a run or hard effort
Tips to Prevent GI Issues
- Establish a pre-run meal routine with easily digestible carbohydrates.
- Make sure to leave plenty of time to digest foods before exercising.
- Keep a log of foods and gels that work best.
- Choose gels with natural sugars (Honey Stinger, Huma, Untapped).
- Start hydrating early in the day and maintain intake throughout.
Refueling After Long Runs
- Eat within one hour post-run for optimal recovery.
- Aim for a 4:1 carb-to-protein ratio (e.g., yogurt with fruit, toast with avocado and eggs, or bagel with eggs).
- Avoid delaying meals, as this slows recovery.
Pre-Race Nutrition
During the taper phase, maintain normal eating habits but increase carbohydrates 3-4 days before race day to 60-75% of daily calories.
- Eat the same foods but gradually increase the amount of carbohydrates. No need to force down extra carbs if you feel full.
- Best carb sources: Rice, pasta, potatoes, oatmeal, fruit.
- Avoid: Fried or high-fiber foods that may cause gastrointestinal (GI) distress.
- Dinner before race: Stick to familiar, carb-rich meals like pasta with marinara, rice with lean protein, or a burrito.
Race Day Fueling
Pre-Race Breakfast (2-3 Hours Before)
- 200-400 calories from carbs + some protein, minimal fat
- Examples: Oatmeal with honey and banana, toast with peanut butter and banana, or toast with jelly.
- Sip 16-20 oz of water leading up to the race.
During the Race (Miles 4-10)
- Runs >80 min: Aim for 30-60g of carbs per hour.
- Options: Energy gels, chews (GU, Clif Bloks, Honey Stinger), sports drinks (Gatorade, Skratch), bananas, dates.
- Hydration: Drink 4-6 oz of fluid every 15-20 minutes, adjusting for sweat rate and weather.
- Electrolytes: Adjust intake based on your training routine and previous electrolyte use.
Post-Race Recovery
- Within 30-60 minutes: Consume a 3:1 carb-to-protein meal (e.g., chocolate milk, protein smoothie and fruit, or yogurt with granola and fruit).
- Within 2-3 hours: Have a well-balanced meal with carbs, protein, and healthy fats (e.g., rice with lean protein and veggies, quinoa with beans and avocado).
- Rehydrate: Drink 16-24 oz of water per pound lost (if you weighed in before and after).
- Electrolytes: Include some electrolytes if you are a heavy sweater.
Final Tips for Half Marathon Nutrition
✔ Train your gut – Practice your fueling strategy during long runs to minimize GI issues.
✔ Stay consistent – Stick with what you know on race day; avoid experimenting.
✔ Listen to your body – Adjust fueling based on energy levels, digestion, and hydration needs.
Fuel well, run strong, and enjoy the race!