How to Fuel Long Runs Without Gut Issues
Fuelling for long runs is a balancing act - eat too little, and you hit the wall. Eat the wrong thing, and you’re doubled over with gut issues.
For many female runners, bloating, cramping, nausea, or unexpected toilet stops can completely derail a training session or race. But good fuelling isn’t just about energy—it’s about digesting and absorbing nutrients properly without discomfort.
If you’ve ever wondered how to fuel long runs without stomach issues, this guide will walk you through:
✅ Why female runners have unique fuelling needs
✅ How hormones impact digestion and carbohydrate metabolism
✅ What to eat before, during, and after a long run
✅ How to train your gut to handle race-day fuelling
✅ Common mistakes that lead to gut distress (and how to avoid them!)
Why Female Runners Have Different Fuelling Needs
Women’s bodies process carbohydrates and fats differently from men’s, particularly due to hormonal fluctuations throughout the menstrual cycle.
How Hormones Impact Fuelling & Digestion
Follicular Phase (Day 1–14, starts with your period)
Higher carb tolerance → Your body efficiently breaks down and stores glycogen.
Better digestion → Less bloating, making it easier to tolerate pre-run meals.
Best time for high-intensity and long runs.
Luteal Phase (Day 15–28, post-ovulation to pre-period)
Reduced carb availability → Your body burns more fat for energy, but running may feel harder.
Slower digestion → Higher chance of bloating, nausea, and gut discomfort.
Increased fluid retention → You may need more hydration and electrolytes.
🔹 Practical takeaway: Track your cycle and test fuelling strategies at different times to see what works best for you.
Best Pre-Run Meals for Long Runs Without GI Issues
Your pre-run meal should:
✅ Provide easily digestible carbohydrates for energy
✅ Include a small amount of protein to stabilise blood sugar
✅ Be low in fat and fibre to prevent bloating
What to Eat Before a Long Run (2-3 Hours Before)
Oats with banana + honey (simple, digestible carbs)
Rice cakes with peanut butter + jam
White toast with almond butter + a drizzle of honey
Plain Greek yoghurt with a handful of granola
A smoothie with banana, protein powder, oats + almond milk
What to Eat If You’re Short on Time (30-60 Minutes Before Running)
Half a banana
A few dates with peanut butter
An energy bar (low-fibre, like a Maurten bar)
200ml sports drink
🚨 Avoid: Greasy foods, high-fibre vegetables, dairy (if sensitive), high-fat snacks, and artificial sweeteners, which can cause bloating and discomfort.
💡 Pro Tip: If digestion is an issue, try a liquid meal (smoothie or sports drink) to reduce stress on the gut.
How to Fuel DURING Long Runs Without Stomach Issues
For runs over 75 minutes, you need 30-60g of carbohydrates per hour to maintain performance. The key is small, steady intake rather than dumping too much fuel in one go.
Best Fuelling Options for Sensitive Stomachs
✅ Energy gels: Maurten, Precision Hydration, Spring Energy
✅ Chews: Clif Bloks, SIS Chews, Skratch Labs
✅ Drinks: Tailwind, Skratch, Maurten 320
✅ Whole food alternatives: Medjool dates, mashed banana, baby food pouches
How Often Should You Take Fuel?
🏃♀️ Every 30-45 minutes: Take one gel, chew packet, or drink sip consistently instead of waiting until fatigue hits.
💡 Pro Tip: Start fuelling early in the run—waiting too long increases GI distress because digestion slows as fatigue builds.
Hydration & Electrolytes: The Overlooked Key to Gut Comfort
Dehydration slows digestion and makes GI distress 10x worse. The right fluid balance is crucial to avoid nausea, cramping, and dizziness.
Hydration Guidelines for Long Runs
✅ 500-750ml of fluids per hour (adjust for heat/humidity)
✅ Electrolytes: Add sodium (Precision Hydration, Tailwind) if sweating heavily
✅ Sip regularly, don’t chug—this helps prevent bloating
Signs You’re Under-Hydrated:
Feeling bloated but thirsty
Sluggish digestion or nausea
Stomach or muscle cramping
💡 Pro Tip: If you bloat during long runs, check if you're overdrinking plain water. Adding electrolytes helps balance fluid absorption.
How to Train Your Gut for Race-Day Fuelling
Many gut issues on race day aren’t caused by food—it’s that the gut isn’t trained to handle fuel while running.
How to Train Your Gut for Fuelling
✅ Start fuelling in training early: Practise with gels, chews, and drinks every long run
✅ Train at race effort: Your gut reacts differently at easy vs. race intensity—practise fuelling at harder efforts
✅ Use the same fuel as race day: Switching brands last-minute = disaster
💡 Pro Tip: Keep a fuelling log to track what you eat before long runs and how you feel. Over time, you’ll figure out what works best.
Common Fuelling Mistakes That Cause Gut Issues
🚨 Eating too much fibre before a run → Leads to bloating and discomfort
🚨 Waiting too long to take in fuel → Harder to digest when fatigued
🚨 Chugging too much water mid-run → Causes bloating and nausea
🚨 Not replacing sodium lost in sweat → Increases dehydration risk
Final Thoughts: Fuelling Smarter = Running Stronger
Fuelling shouldn’t feel like a gamble—by understanding your body’s needs, training your gut, and sticking to simple, digestible foods, you can avoid GI distress and run your best.
🔹 Struggling to find the right fuelling strategy?
🔹 Want a personalised nutrition plan based on your cycle and training?
At Pretty Strong Coaching, I help female runners fuel smarter, train stronger, and recover better—without overcomplicating it.
📩 Click below to book a consultation & dial in your fuelling plan!
Struggling with fuelling on long runs?
At Pretty Strong Coaching, we help female runners train smarter, fuel better, and avoid gut issues—so you can run stronger without hitting the wall. If you're ready for a personalised fuelling strategy that works for your body, let’s chat!
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