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- Half Marathon Fueling Blueprint: The Mistake Costing You Minutes (And How to Fix It)
Half Marathon Fueling Blueprint: The Mistake Costing You Minutes (And How to Fix It)
Jonah Rosner
February 27, 2025
Half Marathon Fueling Blueprint: The Mistake Costing You Minutes (And How to Fix It)
Estimated read time: 3.42 minutes (about as long as it takes me to explain to my mom why I need another pair of running shoes 👟)
Hey Performance Nerds! Jonah here. 🤓
You could be losing 2-4 minutes in your half marathon—without even realizing it. Science says this one fueling mistake might be costing you a PR. Let’s fix it.🏃♂️💨
Today we're breaking down:
🧪 The science of why half marathon fueling is different than a full
⚡️ Exactly how many gels you need (and when to take them)
☕️ The caffeine strategy that could save you 2-3 minutes
🏃♂️ A foolproof fueling plan for your next PR
Let’s dive in.
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The Half Marathon Fueling Myth (And Why It’s Killing Your Performance)
Here’s what actually happens in your body during a half marathon:
🚨 Your muscles store about 90 minutes of high-intensity fuel (glycogen). After that? Your pace drops faster than my phone's battery life. 📱
Even for sub-90-minute races, smart fueling helps you:
🧠 Sharpening focus
⚡ Reducing mental fatigue
🏁 Helping you finish strong
Research shows that taking in carbs during your half can:
✔ Prevent the dreaded late-race fade
✔ Help you maintain goal pace longer
Elite runners fuel during halves. If they need carbs for 13.1, chances are you do too!
Half vs. Full: Why Your Marathon Fueling Plan Won’t Work
⚠️ Warning: Your marathon fueling strategy might be sabotaging your half! Here’s why:
The longer you're running, the more carbs you burn—so marathoners need more fuel. But even in a half, the right fueling keeps you sharp and strong to the finish line.
🏃♂️ Think of it like this: A marathon is a cross-country road trip, but a half is a fast-paced commute. You still need gas, but the strategy is different! ⛽
🛑 What About Elites Running 60-70 Minutes?
If you're finishing in 60-70 minutes, you're right on the edge, a small fuel boost could still help.
Brain benefits? Even if muscles don’t need it, 30-45g of carbs (1-2 gels) might improve mental sharpness and give a brain boost.
Now that you know why fueling matters, here’s exactly how to fuel based on your goal time.
The Ultimate Half Marathon Fueling Guide: Exact Templates By Finish Time
🔬 Research shows that combining caffeine with carbs can amplify the performance benefits of both. Here’s how to dial it in:
Elite Performance Template (Sub-1:15) 🏆
Key Science: At these speeds, your body's like a Formula 1 car - it needs premium fuel delivered in perfect intervals!
Sub-1:30 Speedster Template 💨
Key Science: Your muscles are like a high-performance engine - keep the fuel flowing steadily!
Sub-1:45 Strong Finish Template 💪
Key Science: Perfect balance of performance and comfort. Think of it as cruise control for your energy levels!
Sub-2:00 Smart Racing Template 🧠
Key Science: Just like my dog Augie with his treats, timing is everything!
2:00+ Strong & Steady Template 🌟
Key Science: Consistent energy is your best friend. Like a well-paced Netflix binge!
Your Perfect Caffeine Dose 🧪
Pre-race: 2-3 mg/kg caffeine (~200mg for most runners)
Mid-race (optional): 50-100mg caffeine (gel or drink)
Pre-Race Caffeine Guide 👇
🔑 Pro Tip: Start at the lower end if you haven’t tested higher doses in training. Like my first attempt at making coffee in college, more isn’t always better! ☕
Quick Gel Facts for Half Marathon Success 📝
✔ Best Gels for Half Marathons 🏃♂️💨
Maurten Gel 100 – 👉 Get it here
SIS Beta Fuel Gel – High-carb option (take half for 20-30g of carbs). 👉 Get it here
Precision Fuel & Hydration Gel 👉 Get it here
SIS GO Isotonic Gel - Favorite glucose-only gel 👉 Get it here
✔ Glucose + Fructose: Necessary or Overkill? 🤔
Fueling <50g/hr? ⚡ Glucose alone typically works, but a glucose-fructose mix may help digestion.
Fueling closer to 60+g/hr? 🏃♂️ A 2:1 or 1:0.8 glucose-to-fructose ratio boosts absorption and lowers GI distress.
Sensitive stomach? 😬 Fructose helps process higher carb loads without GI rebellion.
✔ The Science Behind That Last Optional Gel 🧠 (Yes, your brain runs on carbs too!)
Carb rinsing = free speed. Swishing a gel might trick your brain into feeling fresh. 🔋
Brain boost: Not for your muscles—your nervous system gets an energy hit.
Dialing In Your Perfect Strategy 🎯
💪 Hitting the wall despite fueling?
✔ Move your first gel earlier to avoid the bonk
✔ Add 25-50g more carbs to pre-race meal
✔ Increase carbs the day before (6-10g per kg body weight) to maximize glycogen stores.
✔ Check your caffeine timing for max effect
🚽 Too much bathroom stress?
Reduce caffeine by 50mg or cut it altogether
Reduce gels for easier digestion
Practice your gel routine to avoid surprises
Practical Summary ✅
✔ Fuel early—don’t wait until you’re tired
✔ 30-60g carbs/hour based on your pace
✔ Caffeine pre-race can boost performance 2-4%
✔ Practice your strategy in training
✔ Never try new products on race day!
🚨 Zone 2 HR Training DOES NOT MATTER for New Runners
Did you miss my post about why Zone 2 HR Training DOES NOT MATTER for new runners? You can find it below!
I won’t lie. These videos take me a while to make. If you find it helpful, share it on your story or with a friend. It helps me a ton!
Are You a True Running Nerd? Prove it.. 🧐
Welcome to the prove you’re a nerd section. Each week, I ask a question about a common running science myth.
Answer correctly, and you’ll be entered into a weekly raffle to win a package of Jonah’s favorite supplements.
What’s the best strategy to optimize recovery after a long run? |
Last Week’s Results: You Crushed It! 🏃♂️🍞💪
Wow, you all know your post-run nutrition science!
Most of you (162 voters) nailed it—a 1:3 to 1:4 carb-to-protein ratio is the gold standard when you have another hard session the next day.
This range helps your muscles recover and adapt after intense training sessions, keeping you strong and ready to tackle the next challenge. 💪✨
Here’s how the votes stacked up:
⬜️ A. 1:1 (30g carbs + 30g protein) – 19 votes
🟨 B. 1:2 (60g carbs + 30g protein, ~1g carbs/kg body weight) – 68 votes
🟩 C. 1:3 to 1:4 (90-120g carbs + 30g protein, ~1.2-1.5g carbs/kg body weight) – 162 votes ✅
⬜️ D. Just eat whatever you’re craving! 🍕 – 5 votes
Nerdy Finds of the Week 📚🧑🔬
This section includes my favorite research, podcasts or books about running/lifting science.
🏃♀️ Training Zones Simply Explained:
Zone 1 (Easy): 💬 Below first threshold - conversational pace, feels easy
Zone 2 (Moderate): 😅 Between thresholds - "comfortably hard," sustainable but challenging
Zone 3 (Hard): 🥵 Above second threshold - intense effort, heavy breathing, limited duration
📊 Key Training Models:
Polarized: 🔄 Lots of easy + some hard, minimal moderate (80% Z1, 5% Z2, 15% Z3)
Pyramidal: 🔺 Mostly easy, some moderate, little hard (70% Z1, 20% Z2, 10% Z3)
Threshold: ⚖️ Emphasizes moderate intensity
High: ⚡ Emphasizes hard intensity
Low: 🐢 All easy intensity
💡 Main Findings:
😮 Surprising Result: Within a single training block (up to 18 weeks), training intensity distribution by heart rate does NOT significantly influence changes in VO2max or time-trial performance in all endurance-trained athletes
🔍 Important Nuance: When separating by experience level:
Competitive athletes: 🏆 Benefit more from Polarized training
Recreational athletes: 🏃♂️ Benefit more from Pyramidal training
🔬 Key Insights:
🧪 Age, sport, baseline VO2max, and training duration did NOT influence results
⭐ Only athlete performance level affected the optimal training approach
💪 Competitive athletes may have greater capacity to work at higher intensities
📈 Recreational athletes have more room to improve regardless of training model
⏱️ 3-18 week training blocks don't tell us about long-term periodization effects🛠️ Practical Takeaways:
🛠️ Practical Takeaways:
🔄 MOST IMPORTANT: Maintain consistent training over time - any appropriate plan that you can stick with beats perfect programming with poor adherence
📆 Choose a training approach you can sustain long-term over what seems optimal on paper
🧩 If you compete at higher levels: Focus on easy training with strategic hard sessions
🌱 If you're recreational: Moderate-intensity work with your easy training is most likely enough to improve!
🏗️ Build a sustainable training habit before optimizing intensity distribution
🎯 Bottom Line:
For short-term training blocks, the overall intensity distribution matters less than we thought! Consistency trumps perfection.
Choose a sustainable approach guided by your experience level: competitive athletes benefit from polarized training while recreational athletes might do better with a pyramidal approach.
Don’t forget: You + Science = AWESOMENESS 😎
Yours in science,
Jonah
P.S. - We have a crew of 15,270+ nerds here who are running FAST using science.
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