Runner's Fueling Guide: When to Increase Your Carb Intake
HEALTH & NUTRITION
How to Know When to Add More Carbs to Your Plate
Carbohydrates are a runner’s primary fuel source, but many athletes unknowingly underfuel—especially when training ramps up. While hunger is one cue that you may need more food, it’s not always reliable, especially for runners balancing high mileage, strength training, and busy lifestyles given that hunger cues are sometimes reduced during periods of stress.
So how do you know when to add extra carbs to your plate? If you’re increasing your training load, intensifying your workouts, or simply spending more time on your feet, it’s time to adjust your fueling strategy. Here’s when you should be adding more carbohydrates to support your performance and recovery.
1. When You’re Increasing Mileage
As you log more miles, your body burns through more glycogen (stored carbohydrates in your muscles and liver). If you don’t replace what you’re using, you’ll eventually hit a wall—leading to sluggish runs, fatigue, and longer recovery times.
Signs you need more carbs:
✔️ You feel drained by the end of the day ✔️ Runs feel harder than usual ✔️ You’re struggling to hit paces that used to feel comfortable
Easy ways to add more carbs:
Add an extra serving (I like to say a serving is a fist of cooked starch) of rice, potatoes, or pasta at meals
Include more fruit, honey, or dried fruit to yogurt parfaits or oatmeal
Add an extra snack to your day loaded with carbs like whole grain toast, a bowl of cereal or fruit (balanced with protein or fat such as peanut butter, a hard boiled egg, milk or nuts)
2. When You’re Increasing Intensity (Lifting or Speedwork)
When you add strength training, tempo runs, or interval sessions to your routine, your energy demands increase. High-intensity work relies heavily on carbohydrates, and underfueling can lead to muscle breakdown and poor performance.
Signs you need more carbs:
✔️ You’re feeling more sore than usual after workouts ✔️ You’re struggling to recover between hard sessions ✔️ Your sleep is disrupted or you feel restless at night
Easy ways to add more carbs:
Have a high-carb snack (like toast with jam) 30-60 minutes before speedwork
Add starchy vegetables (like sweet potatoes or corn) to dinner
Drink a sports drink during pre-workout snack to increase carbs without increasing satiety
3. When You’re Doing Two-a-Days
If you’re running and lifting on the same day or splitting your workouts into morning and evening sessions, your body needs extra fuel to keep up with the demand.
Signs you need more carbs:
✔️ You feel lightheaded or sluggish during your second workout ✔️ Your muscles feel depleted instead of energized ✔️ You’re experiencing more frequent sugar cravings
Easy ways to add more carbs:
Eat a carb-heavy snack/meal paired with 20+ grams of protein (that’s about a palm sized portion of meat or 1.5 cups of beans) between workouts to make up for the fact that you’ll be working out again soon after! Good ideas are chickpea pasta based meals, turkey sandwich with pretzels and fruit, or a smoothie packed with carbs from dates, juice/sweetened nut milk and protein powder.
Prioritize a recovery meal with at least 50-75g of carbs after your first session
Use sports drinks or energy chews if your second session feels like a struggle
4. When You’re More Active Outside of Training
It’s not just structured workouts that burn energy—if you’re spending more time walking, standing, or chasing kids around, your energy needs go up. Non-exercise activity can significantly impact your total calorie burn, even if it doesn’t feel like a workout.
Signs you need more carbs:
✔️ You feel more tired at the end of the day than usual ✔️ You’re hungrier than normal but not adjusting your intake ✔️ You’re experiencing low energy on runs even though training hasn’t changed
Easy ways to add more carbs:
Eat a balanced breakfast with carbs + protein (e.g., eggs with toast or oatmeal with nuts)
Keep high-carb snacks on hand (e.g., trail mix, dried fruit, granola bars)
Add an extra portion of carbs at lunch or dinner
The Bottom Line
Runners need to adjust their carb intake based on training load, intensity, and daily activity levels. If you’re increasing mileage, doing more speedwork, training twice a day, or simply moving more throughout the day, your body needs extra fuel—and carbs are the best way to provide it.
Instead of waiting for signs of underfueling like fatigue, poor recovery, or sluggish workouts, be proactive about adding high-quality carbohydrates to your meals and snacks. Your performance, energy, and recovery will thank you!
PMID: 28919842
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