🥪 Ultramarathon Nutrition Guide – Fueling Strategies for 50K, 50M & 100M Races

🎯 Fuel Smart, Go the Distance

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📌 Why Nutrition Can Make or Break Your Race

Imagine spending months training for an ultramarathon—only to DNF at mile 70 because your stomach revolted or your energy vanished. Nutrition is not a side note in ultra racing—it’s one of the central pillars of success. In races lasting 6, 12, 24 hours or more, your performance hinges less on peak VO2 and more on your ability to fuel steadily, digest efficiently, and adapt your plan as the race unfolds.

Many runners “bonk” because they either underfuel (not enough calories), underhydrate (not enough fluids or electrolytes), or gut out (GI shutdown from stress, pace, or bad food choices). This guide breaks down how to avoid all of that—with real strategies and race-tested wisdom.

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🔥 Fueling Basics: What Your Body Needs During an Ultra

Your body runs on two main fuel sources:

1. Carbohydrates (glycogen + ingested sugar)
2. Fat (stored body fat and dietary fat)

During an ultramarathon, you want to maximize carbohydrate intake without upsetting the gut, while relying on a steady trickle of fat metabolism. Here’s what this means practically:

⚡ Energy Needs per Hour (General Guidelines):

• 200–300 kcal/hour is the average fueling range.
• Smaller runners may need 150–200 kcal, larger runners 250–350 kcal.
• This equates to about 40–60 grams of carbs/hour, ideally a mix of glucose and fructose.

🧠 Why Not Just Eat More?

Because digestion slows during intense or prolonged exercise, especially in the heat. Your goal is not to fill your stomach—but to absorb usable fuel at a consistent rate. That’s where smart choices come in.

🧮 How to Calculate Your Fueling Needs: Macros for 50K–100M

Fueling for an ultramarathon isn’t one-size-fits-all. Your calorie, carbohydrate, fluid, and electrolyte needs depend on body weight, race duration, terrain, temperature, and even gut training. Here’s a quick guide to help you estimate your needs.

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🏃 Step 1: Estimate Your Hourly Calorie Needs

Body Weight (kg)	Light Effort (kcal/hr)	Moderate Effort	High Effort
50–60	180–200	220–250	270–300
60–70	200–230	250–280	300–350
70–80	220–250	270–300	350–400
80–90	240–270	300–330	370–420

📌 Pro Tip: Start with the middle range for your expected race pace, then adjust based on previous experience.

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🍞 Step 2: Calculate Carbohydrate Intake

• Goal: 30–90g of carbs/hour
• Endurance sweet spot: 60g/hour from a mix of glucose + fructose

Example:

If your gel provides 25g of carbs → You’ll need ~2 per hour + some drink mix or chews.

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💧 Step 3: Fluid & Electrolyte Needs

🔹 Fluid:

• 500–750 ml/hour depending on heat and sweat rate
• Use training runs to test tolerance and gut absorption

🔹 Sodium:

• 400–800 mg/hour is a safe range for most
• Sweat-heavy runners may require 1000+ mg/hr

Sweat Level	Sodium Loss/Hour	Suggested Strategy
Low	400–500 mg	Light electrolyte drink or tab every 90 mins
Moderate	600–800 mg	Salt tab or sports drink every hour
Heavy	800–1200+ mg	Salt tabs + high-sodium drink + salty food

📌 Tips to Apply These Numbers in the Real World:

Track performance: energy, GI response, clarity

Break totals into hourly packs (“Hour 1: 1 gel, 1 chew, 1 salt tab”)

Practice weekly long runs with these exact ratios

Pre-label fuel bags by hour: “Hour 3 = 250 kcal, 60g carbs, 600ml, 1 tab”

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🍭 Fuel Types: The Good, the Useful & the Ugly

There’s no “perfect” fueling strategy—but there are smart combinations that reduce palate fatigue, GI distress, and energy dips. Let’s look at the options:

1️⃣ Energy Gels / Chews / Blocks

• ✅ Fast-acting, compact, and widely used.
• ⚠️ Can be too sweet over time, leading to palate fatigue or nausea.
• 📌 Try rotating flavors and brands (citrus, cola, ginger-based help with nausea).

2️⃣ Sports Drinks & Liquid Calories

• ✅ Provide hydration, carbs, and electrolytes in one shot.
• Popular options: Tailwind, Maurten, Skratch, Precision Fuel.
• ⚠️ Too much liquid fuel can overwhelm the gut—balance with plain water.

3️⃣ Solid Foods (aka Real Food)

• Examples: banana halves, PB&J mini sandwiches, dates, rice balls, salted potatoes.
• ✅ Great for longer races (50 miles+), when the body craves something substantial.
• ⚠️ Require chewing, saliva, and sometimes a slower pace to digest.

4️⃣ Soup, Broth, and Noodles (100M Races)

• ✅ Salt-rich, easy to digest, warming at night stages.
• Widely used in 100M aid stations; mentally comforting and gut-friendly.

5️⃣ Fueling Innovations

• “Superstarch” (e.g., UCAN): slow-digesting carbs for stable blood sugar
• Keto-adapted products: MCT oil, nut butter fuels (for fat-adapted athletes only)
• Functional gels: Caffeine, BCAA, beta-alanine enhanced options

⚙️ Mix & Match Strategy

Avoid over-relying on one type of fuel. Alternate sweet and savory. Rotate textures. Pack “rescue” snacks like ginger candy or electrolyte gummies for late-race stomach rescue.

🧃 Popular Ultramarathon Fuel Products: Comparison Table

Ultrarunners have more fuel choices than ever. From classic energy gels to drink mixes and real-food alternatives, knowing which product fits your race strategy is key. Here’s a comparison of some of the most popular ultra fueling products, organized by category and features:

🔍 Fuel Product Comparison Table

Product	Type	Carbs/Serving	Electrolytes	Notes
Maurten Gel 100	Gel (Hydrogel)	25g	Minimal	Neutral taste, gentle on gut, pricey
Tailwind Endurance	Drink Mix	25g/100 cal	300 mg Na	Balanced carb + salt, light flavor
Spring Energy	Real Food Gel	17–30g	Low	Made from natural food, thicker texture
SIS Beta Fuel	High-Carb Drink	80g/500ml	200 mg Na	Great for high-carb intake (2:1 ratio)
Huma Gel	Fruit Puree Gel	21g	100 mg Na	Vegan, chia seeds help slow release
Clif Bloks	Chews	24g (3 pieces)	50–100 mg Na	Easy to dose, multiple flavors
Precision Hydration	Drink Mix/Tabs	Varies	Customizable	Sweat test matched, used by pros
UCAN SuperStarch	Slow Carb Powder	25g	None	Long-lasting energy, not for all guts
Ginger Chews	Solid	Low	None	Useful for nausea—not main fuel

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🧠 Choosing the Right Combo

Use this table to identify your fueling base, complement, and rescue item:

• Base Fuel = gels or drinks you can consume regularly (e.g., Tailwind + Huma)
• Complement = solids for longer races or taste fatigue (e.g., Spring, Clif Bloks)
• Rescue Items = cola, broth, ginger, or caffeine for gut reset or energy hit

📌 Pro Tip: Try all products in long runs. Your gut is the real lab.

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🗺️ Example Fueling Plans by Distance

Let’s break down realistic fueling strategies based on race length:

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🏃‍♀️ 50K Race Nutrition

• Calories: ~200–250 kcal/hour
• Fuel Type: Mostly gels, soft chews, maybe one or two mini solid snacks
• Hydration: Water + electrolyte mix or sports drink
• Timing:
  • Every 30 mins: 1 gel
  • Every hour: sip sports drink or add electrolyte tab to soft flask
  • Optional: banana or half PBJ at aid stations

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🏃‍♂️ 50 Mile / 100K Nutrition

• Calories: ~250–300 kcal/hour
• Fuel Type: Gels + solids (bananas, trail mix, soft sandwiches)
• Hydration: Mix of water and sports drink
• Timing:
  • First 3 hrs: focus on gels/chews (fast digestion)
  • Mid-race: add real food at aid stations
  • Night or late stages: warm broth, salty soup, ginger ale if stomach is off

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🏔️ 100 Mile Fueling Strategy

• Calories: 250–350 kcal/hour depending on pace/body size
• Fuel Type: Gels, drinks, real food, hot meals at night (e.g., ramen, mashed potatoes)
• Hydration: Alternate water and electrolyte drink
• Timing Sample:
  • Hour 0–2: Gels + sports drink
  • Hour 3–6: Add soft solids (banana, sandwich)
  • Hour 6+: Alternate gels, soup, broth, solid food
  • Nighttime: Caffeinated gels or coffee, salty warm foods
  • Final stretch: quick sugar hits, gum, sips of soda if gut allows

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📦 Pro Tip: Label Everything

If you use a drop bag or crew, label your food bags with time estimates (“Mile 40 Lunch,” “Night Food”) and flavor types (“Sweet”, “Savory”, “Salty”) to avoid decision fatigue.

🏁 Case Study: Real Fueling Plan for a 100-Mile Ultramarathon

Let’s walk through a real-world fueling plan for a 70 kg, sub-24-hour 100-mile runner. This runner has completed multiple ultras, has trained their gut to handle ~60–70g carbs/hour, and uses both crew and drop bags.

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🧍‍♂️ Runner Profile

• Weight: 70 kg
• Race Goal: Finish under 24 hours
• Environment: Mountain course, 3500m elevation gain, cold night, warm day
• Gut Training Level: High
• Fuel Preference: Mix of liquid calories, gels, and real food

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⏱️ Sample Race Day Nutrition Timeline

Time (Race Hour)	Calories	Fuel Used	Notes
Hour 0–2	500–600	Tailwind + Huma Gel every 45 min	Start conservative, rotate flavors
Hour 3–5	600–700	Spring Energy Gel + Banana + Drink Mix	Gut still stable, small real food added
Hour 6–9	750–900	Rice ball + PB&J half + Ginger chew	Mid-race real food + palate reset
Hour 10–13	700–800	Broth + Soft Chews + Flat Coke	Nightfall begins, warmth + sugar spike
Hour 14–17	600–700	Tailwind + Caffeine Gel + Salty Crackers	Keep pace strong, avoid nausea
Hour 18–22	800–900	Soup + Noodles + Chew + Coffee	Cold temps + fatigue = comfort fuels
Hour 22–24	400–500	Cola sips + Gels + Gum	Final push, mental boost focus

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🧠 What Made This Work?

• Gut Training: Everything tested in training; no new fuel on race day
• Diverse Fuel Mix: Gels for fast energy, real food for satisfaction
• Palate Strategy: Switched from sweet → salty → caffeine intentionally
• Crew System: Pre-packed labeled fuel bags by hour and phase
• Electrolyte Consistency: Salt tab every 90 minutes, drink mix used throughout

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📦 Drop Bag Inclusions:

• Backup fuels in each: Tailwind single-serve, gels, ginger chews
• Warm layers + dry socks with every nutrition kit
• Mini “Emergency Snack Pack”: peanut butter bite, caffeine gum, mini cola bottle

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🧭 “My body was sore, my feet ached, but my stomach never quit. That’s why I finished.”
— Ultra finisher, 2024

💧 Fueling for the Long Haul: Hydration, Gut Training & GI Troubleshooting

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💦 Hydration & Electrolyte Balance: Not Just About Water

Too many runners treat hydration as an afterthought—until they’re dizzy, cramped, or peeing brown. In an ultramarathon, fluid loss, sodium depletion, and even overhydration can all wreck your race.

✅ General Hydration Guidelines:

• 500–750 ml/hour of fluid intake depending on weather, sweat rate, and effort
• Alternate water and sports drinks—don’t rely solely on either
• Electrolytes are essential, not optional

🧂 Electrolyte Strategies:

• Salt tablets (e.g., SaltStick, S-Caps) every 1–2 hours (depending on sweat rate)
• Electrolyte drink mixes (Precision Hydration, LMNT, Nuun, Tailwind)
• Salty food: pickles, chips, broth
• Adjust per conditions: More sodium needed in hot & humid races

⚠️ Watch for Hyponatremia:

• Drinking too much plain water without sodium can cause sodium dilution = dangerous
• Symptoms: nausea, confusion, bloating, swelling fingers
• If bloated → pause water, take sodium, reassess

👀 How to Monitor Hydration:

• Light straw-yellow urine = good
• Dark amber = dehydrated
• Clear and excessive = possible overhydration

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🧪 Train Your Gut Like You Train Your Legs

The biggest nutrition mistake? Trying something new on race day.

🛠️ Gut Training 101:

• Start fueling in training runs of 90+ minutes
• Increase carbohydrate intake gradually: 30 → 60 → 90 g/hour
• Practice fueling every 30 minutes even when you don’t “feel hungry”
• Simulate race conditions: Same time of day, gear, pace, heat if possible

🔄 Sample Gut Training Plan:

Week	Long Run	Carb Goal	Fuel Used
1	90 mins	30g/hr	1 gel/hr
2	2 hrs	45g/hr	Gel + chews
3	3 hrs	60g/hr	Gel + drink mix
4	3+ hrs	75–90g/hr	Add soft food

📌 Note: Every gut is different. The goal is absorption efficiency, not just consumption volume.

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🤢 Avoiding and Managing GI Distress During Ultras

Even with perfect planning, ultras are unpredictable. Here’s how to troubleshoot the most common stomach issues.

🧭 GI Troubleshooting Table:

Symptom	Likely Cause	Quick Fix
Nausea	Overfueling, heat, sugar overload	Slow pace, sip ginger ale, bland food
Bloating	Too much fluid or fiber	Switch to water only, stop solids
Cramps	Sodium or magnesium deficit	Take salt tab or electrolyte drink
Vomiting	Overexertion, stress	Rest at aid station, reset with broth
Diarrhea	Fructose overload or nerves	Avoid high-FODMAPs, hydrate carefully
Bonking	Caloric deficit	Quick carbs: gel, cola, candy
No appetite	Late-race fatigue	Liquid calories, warm broth, coffee

🧪 Advanced Troubleshooting: What to Do When Everything Goes Wrong

Even with solid planning, ultramarathons can go sideways fast. Your gut, mind, or energy systems might hit a wall — often all three at once. Here’s how to troubleshoot the most common extreme race-day issues that can derail even elite runners:

🌀 Symptom: Vomiting or Severe Nausea

What it feels like: Can’t keep food or fluids down, stomach feels tight or spinning.
Why it happens: Heat stress, overhydration, too many carbs at once, or altitude.

What to do:

• Stop running for 5–10 minutes, sit or lie down if possible.
• Sip cold ginger ale, soda, or broth slowly — not gulping.
• Switch to liquid-only calories if digestion is compromised.
• Mentally reset: nausea often triggers panic → which makes it worse.

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🔁 Symptom: Gut Shut-Down (Can’t Eat Anything)

What it feels like: Stomach feels “full”, even if you haven’t eaten. Everything repulses you.
Why it happens: Blood diverted from gut → digestion slows dramatically.

What to do:

• Slow your pace. This is critical.
• Take 10–15 mins of walking, sip small amounts of liquid calories.
• Try neutral-flavored items (e.g., plain bread, broth, mashed potatoes).
• Avoid caffeine and gels until your gut settles.

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⛔ Symptom: “Bonk” That Doesn’t Respond to Sugar

What it feels like: No energy, dizzy, possibly emotional or confused.
Why it happens: You waited too long to fuel — or misjudged salt/hydration.

What to do:

• Take quick-absorbing sugar (gel or soda), and follow with electrolyte drink.
• Walk and wait 10–15 minutes for sugar to enter bloodstream.
• If still weak: sit at aid station, reset with food + salt combo.
• Don’t give up: full bounce-back is common after 15–30 minutes!

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🧊 Symptom: Cold, Shivering & Low Energy at Night

What it feels like: Teeth chattering, feeling tired beyond normal.
Why it happens: Low calories, wet clothes, slowed pace, nighttime chill.

What to do:

• Add extra layers (even emergency foil blanket).
• Drink or eat hot calories: soup, noodles, tea.
• Stay near aid station fire or shelter until body temp rises.
• Don’t underestimate calories as heat — eat more before moving on.

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🧠 Final Mental Reset Tip:

When in doubt, say to yourself:

“This is temporary. I can come back.”
Even elite runners suffer through hours of misery — and still finish strong.

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🔥 Golden GI Rules

1. Fuel Early, Fuel Often: Start eating in the first hour, not when you feel hungry.
2. Chew & Sip: Don’t slam a gel and gulp water all at once.
3. Cool = Digestible: Heat reduces gut blood flow—slow down if you’re overheating.
4. Avoid Fiber Pre-Race: No raw veggies, nuts, or whole grains 24–36 hours before race
5. Emergency Fuel Kit: Always pack backup: ginger candy, mint gum, cola, electrolyte capsules

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🛡️ Mental Fortitude & GI Stress

A huge part of nausea and gut shutdown during ultras comes from mental fatigue and pacing errors. If you feel sick:

• Ask yourself: “Am I pushing too hard?”
• Slow your pace, breathe deeply, and reset.
• Sip something comforting (e.g., warm broth or cold soda), and give yourself 10–15 minutes.

🧠 Fuel Like a Pro: Planning Tools, Gear, Wisdom & Interactive Content

📋 Nutrition Planning Templates & Tools

Ultramarathon fueling should never be left to chance. These tools and templates help you prepare your strategy with precision:

✅ Printable Fueling Timeline (PDF)

• Hour-by-hour fueling breakdown for 50K, 100K, and 100-mile races
• Recommendations adjusted for temperature, elevation gain, and aid station frequency
• Bonus sections: “Palate Reset Foods”, “Emergency Fuel Options”, and caffeine timing chart

✅ Editable Google Sheet: Race Nutrition Planner

• Build your custom calorie, fluid, and electrolyte intake plan for any race
• Log and evaluate products you’ve tested in training
• Plan daily carbohydrate loading in the days leading up to race day

✅ Fueling Practice Log

• Record what products you’ve tried, when, how much, and in what conditions
• Track GI responses, energy levels, and pacing compatibility
• A vital tool to refine your plan and avoid race-day surprises

🧠 Pro Tips From Coaches & Elite Runners

Ultramaraton dünyasının ustalarından beslenme ipuçları:

🗣️ “Eat early, eat often. You’re always behind on calories—don’t wait to catch up.”
— Courtney Dauwalter, multiple 100M wins

🗣️ “If your gut is trained, your mind doesn’t panic when food feels heavy.”
— Zach Bitter, 100-mile world record holder

🗣️ “No matter how clean your diet is, a cola at mile 70 is a miracle.”
— Camille Herron, Comrades & 100-mile champion

📌 Pro Tip: Plan for mental food cravings—not just physical needs. Sweet, salty, crunchy, hot, cold… organize by flavor + function.

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🎒 Fuel-Carrying Gear You Can Trust

The right gear makes or breaks your fueling plan. A few field-tested favorites:

🎽 Vests & Belts

• Salomon ADV Skin, UltrAspire Alpha, Nathan VaporAir
• Must-haves: easy-access front pockets, bounce-free fit, room for solids

🍼 Soft Flasks vs Bladders

• Soft flasks = easier monitoring + switching between drinks
• Bladder = more fluid, less access; use mainly in hot races with fewer aid stations

🥪 Fuel Organization

• Ziplock bags labeled by mile/time
• Bento boxes, flask holders with snack compartments
• Emergency stash in rear vest pocket (sugar, salt, caffeine)

📦 Crew/Drop Bag Labeling

• Label by mile, time estimate, contents (e.g., “Mile 60 – Noodles + Ginger Ale”)
• Use color-coded systems for “normal”, “emergency”, “stomach-safe”

🎒 Crew Nutrition Strategy & Drop Bag Tips

While fueling gear keeps you moving, your crew and drop bags are your mobile kitchen. In 100K and 100-mile ultras, having a smart nutrition setup for aid stations, drop bags, and crew can make or break your race.

👥 If You Have a Crew: Maximize Their Impact

Your crew isn’t just moral support—they’re your nutrition team. Here’s how to set them up for success:

✅ Key Crew Nutrition Tactics:

• Label fuel bags by mile/time (e.g., “Mile 50 – Day Food”, “Mile 75 – Night Kit”)
• Pack by flavor & type: “Sweet / Savory / Liquid / Emergency”
• Give them a printed checklist of what you need at each stop:
  • Refill soft flask with Tailwind
  • Hand over salt caps & chews
  • Ask: “Have you eaten in the last 30 minutes?”

📦 Optional Kit: “Fuel Mood Cards”

• Green = Ready for everything
• Yellow = Sweet fatigue, want salty
• Red = Nauseous, need ginger or broth
  Use simple colors or emoji stickers to communicate fast when words are hard.

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📦 Drop Bag Nutrition Strategy (No Crew? No Problem.)

You may not have a crew, but with smart drop bags, you can still stay fueled and ready.

🧰 Best Practices:

• Double-bag items with Ziploc or waterproof pouches
• Use color-coded labels: “Breakfast Fuel”, “Night Food”, “Emergency”
• Include:
  • Replacement fuel (gels, drink powder, mini-meals)
  • Gut reset items (ginger candy, antacids, baby food)
  • Mood boosters (your favorite snack or cold cola)

🔁 Drop Bag Fuel Rotation Tip:

Divide your nutrition into phases:

• Bag 1 (Start–Mile 30) → Mostly gels and fast fuels
• Bag 2 (Mile 50–70) → Add solid food, salt, caffeine
• Bag 3 (Night / Mile 80–Finish) → Broth, warm food, soft sugar, cola

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🧠 Elite Insight:

“I treat my crew like a Formula 1 pit team. Everything is rehearsed. Fuel goes in, gear gets swapped, and I’m out.”
— Anonymous 100-mile finisher

🍌 What should I eat during a 100-mile ultramarathon?

Gels, drink mixes, soft real foods (bananas, rice balls, PB&J), warm broth, and occasional caffeinated items in later stages.

💧 How much water should I drink per hour?

Typically 500–750ml/hour depending on effort, heat, and sweat rate. Adjust with experience and gut comfort.

🧂 Do I need salt pills if I use sports drink?

Maybe not—but in hot races or if you sweat heavily, extra sodium from salt pills can prevent cramps and hyponatremia.

🤢 What should I do if I feel nauseous mid-race?

Slow down, sip ginger ale or broth, switch to bland foods. Let your gut catch up and reset.

🍬 Can I use only energy gels?

For short races, yes. But for 100K or 100M, your gut may reject only-sweet fuels. Add real food for balance.

📈 What is “training the gut”?

Gradually increasing your carb intake per hour in training runs to improve absorption and reduce race-day GI issues.

🥤 What are signs of hyponatremia?

Swelling hands, bloating, nausea, confusion. Happens when drinking too much plain water without sodium.

🕓 How often should I eat?

Every 25–45 minutes is a solid window. Gels or chews every 30 mins, solids every 60–90 mins.

🍲 Can I eat soup or noodles during a race?

Yes—especially in longer races. Warm, salty, easy-to-digest meals are common at night or cold segments.

🚽 What causes runner’s diarrhea?

Often fructose overload, stress, or high fiber. Avoid unfamiliar food and test all fuels in training.

🧪 Quiz – “Are You Ready to Fuel 100 Miles?”

❓ Questions (Emoji Numbered)

1️⃣ What’s the recommended carb intake per hour during an ultramarathon?
A) 10–20g
B) 30–60g
C) 70–90g
D) 100–120g

2️⃣ What’s the best fuel for the first hour of a 50K?
A) Ramen noodles
B) Energy gels
C) Bananas
D) Chocolate bars

3️⃣ What is palate fatigue?
A) A muscle issue
B) Repetitive taste exhaustion
C) Overhydration
D) Low sodium levels

4️⃣ When should you start fueling during a 100M race?
A) After 2 hours
B) After the first aid station
C) Within the first 30–45 minutes
D) At the halfway point

5️⃣ Which is NOT a sign of hyponatremia?
A) Clear urine
B) Nausea
C) Swollen fingers
D) Sharp calf pain

6️⃣ What’s the main advantage of soft flasks over bladders?
A) They carry more
B) Easier to refill
C) Cheaper
D) Less taste

7️⃣ What’s the best way to train your gut?
A) Eat fiber-rich meals
B) Fuel only during races
C) Practice fueling during long runs
D) Skip breakfast before long runs

8️⃣ What food is best for mid-race nausea?
A) Candy
B) Spicy chips
C) Ginger ale or broth
D) Raw carrots

9️⃣ How do elite runners manage late-race fueling?
A) Eat nothing
B) Eat large meals
C) Use caffeine & quick sugar
D) Drink only water

🔟 What’s a smart way to organize your fueling gear?
A) Toss everything in one bag
B) Label by flavor
C) Label by time/mile and flavor
D) Use only liquid fuels

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✅ Quiz Answers:

1: B | 2: B | 3: B | 4: C | 5: D | 6: B | 7: C | 8: C | 9: C | 10: C