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PlanB Coaching > Blog > Uncategorized > Complete Nutrition Guide for the most common races.
Completing a Half Ironman (70.3 miles) is a huge endurance feat, requiring not just physical training but also smart nutrition. Proper fueling can make the difference between hitting the wall and crossing the finish line strong. In this guide, we’ll break down how to fuel before, during, and after your race to maximize performance.
A 70.3 race typically takes 4 to 7+ hours to complete, demanding significant energy expenditure. Without proper fueling, you risk:
Bonking (running out of glycogen)
Dehydration and electrolyte imbalances
GI distress (stomach cramps, nausea, diarrhea)
Reduced performance and muscle fatigue
To avoid these issues, you need a solid nutrition plan tailored to your body and race conditions.
Your nutrition strategy starts days before the race, not just the morning of.
Increase carbohydrate intake to ~7-10g per kg of body weight to maximise glycogen stores.
Focus on complex carbs (brown rice, pasta, sweet potatoes, oats) and avoid excessive fiber to prevent GI issues.
Stay hydrated with electrolytes (sodium, potassium, magnesium).
Eat a familiar, easily digestible meal (e.g., rice with lean protein, roasted veggies).
Avoid high-fat, high-fiber, or spicy foods that could upset your stomach.
Consume ~300-500 calories from easily digestible carbs (banana, toast with honey, oatmeal).
Include a small amount of protein/fat (peanut butter, eggs) if tolerated.
Hydrate with 16-20 oz of water + electrolytes.
Avoid caffeine if you’re not used to it (or stick to your normal intake).
The key to race-day success is consistent fueling—don’t wait until you’re hungry or thirsty.
Take a gel about 10 mins before you enter the water. Usually in the queue to get started.
Aim for 60-90g of carbs per hour (more if you’re well-trained in high carb intake).
Use a mix of liquid nutrition (sports drinks, gels) and solid foods if tolerated.
Electrolyte tabs can be added to sports drinks to prevent cramping.
Hydration: 20-30 oz of fluid per hour (adjust for heat/sweat rate).
Example Bike Nutrition Plan:
Hour 1: 1 bottle sports drink (60g carbs) + packet of 30g Chews
Hour 2: 1 bottle sports drink (60g carbs) + packet of 30g Chews
Hour 3: 1 bottle sports drink (90g carbs)
Switch to quick-digesting gels
Aim for 30-60g carbs/hour (some athletes tolerate less due to stomach sensitivity).
Take small sips of water at aid stations to avoid sloshing.
If needed, use caffeine (100-200mg) in the later stages for a mental boost.
Example Run Nutrition Plan:
As soon as you get on to run: Take a gel
Every 30 mins: Take another gel
Caffeine: Switch to caffeine for the last 2/3 gels you plan to take. The amount of gels you require will depend on how fast you are running
Pro Tip: Practice your race-day nutrition in training to avoid surprises!
Recovery starts as soon as you cross the finish line. Prioritize:
Fast-acting carbs (fruit, recovery drink) within 30 minutes.
Protein (20-30g) to repair muscles (chocolate milk, protein shake).
Electrolytes + hydration (coconut water, electrolyte drink).
A balanced meal within 2 hours (carbs + protein + healthy fats).
❌ Waiting too long to eat/drink → Bonking
❌ Overloading on fiber/fat → GI distress
❌ Trying new foods on race day → Stomach issues
❌ Skipping electrolytes → Cramping
A smart fueling strategy is just as important as your training. Test different foods, hydration, and carb amounts in long workouts to find what works best for you. On race day, stick to your plan, adjust as needed, and trust your preparation.
Now go crush that 70.3! 🚴♂️🏊♂️🏃♂️
Completing an Ironman (140.6 miles) is one of the toughest endurance challenges out there—and without proper fueling, even the fittest athletes can hit the wall. Your nutrition strategy is just as critical as your training. In this guide, we’ll break down how to fuel before, during, and after your Ironman to maximize performance, avoid bonking, and cross the finish line strong.
An Ironman can take 8 to 17+ hours to complete, meaning:
You’ll burn 5,000–10,000+ calories
Your glycogen stores will deplete multiple times
Dehydration and electrolyte imbalances can derail your race
GI distress (nausea, bloating, diarrhea) is common if fueling is off
To survive and thrive, you need a personalised, well-practiced nutrition plan.
Your body can’t store enough glycogen for a full Ironman, so carb-loading is essential.
Increase carbs to 8–12g per kg of body weight (e.g., 400–600g/day for a 150lb athlete).
Focus on complex carbs (brown rice, pasta, sweet potatoes, oats) and reduce fiber as race day nears.
Maintain hydration with electrolytes (sodium, potassium, magnesium).
Eat a familiar, high-carb, low-fiber meal (e.g., white rice + grilled chicken + steamed veggies).
Avoid heavy fats, excessive protein, or spicy foods.
400–600 calories from easy-to-digest carbs (bananas, toast with honey, oatmeal).
Small protein/fat source (peanut butter, eggs) if tolerated.
Hydrate well (16–24 oz of water + electrolytes).
Caffeine (if used to it) for an alert start.
Start fueling early—don’t wait until you’re hungry or thirsty.
Aim for 60–90g carbs/hour (some elite athletes go up to 100–120g).
Mix fuel sources (liquid + solid) to avoid gut fatigue.
Electrolytes are critical (700–1,000mg sodium/hour in hot conditions).
Practice in training! Never try new foods on race day.
You won’t eat during the swim, so top up glycogen beforehand.
In T1, grab a quick gel or sip of sports drink if needed.
Liquid carbs + chews
Electrolytes (via tabs or drink mix).
Hydration: 24–32 oz per hour (adjust for heat/sweat rate).
Example Bike Nutrition Plan:
Hour 1: 1 bottle sports drink (60g carbs) + packet of 30g Chews
Hour 2: 1 bottle sports drink (60g carbs) + packet of 30g Chews
Hour 3: 1 bottle sports drink (60g carbs) + packet of 30g Chews
Switch to easily digestible carbs (gels, coke, flat soda).
Lower intake slightly (40–70g/hour) if stomach is sensitive.
Walk aid stations to ensure proper drinking/fueling.
Caffeine (100–200mg) in later stages for a mental boost.
Example Run Nutrition Plan:
As soon as you get on to run: Take a gel
Every 30 mins: Take another gel
Caffeine: Switch to caffeine for the last 2/3 gels you plan to take. The amount of gels you require will depend on how fast you are running
Pro Tip: Set a timer on your watch to remind you to eat/drink every 20–30 mins!
❌ Starting too late → Bonking by mile 80 on the bike
❌ Overloading on sugar → GI distress
❌ Skipping electrolytes → Cramping, dizziness
❌ Trying new foods → Stomach disaster
❌ Drinking too much plain water → Hyponatremia (low sodium)
Your body will be in extreme depletion—refuel wisely:
Within 30 min: Fast carbs (fruit, recovery drink) + protein (20–30g).
Within 2 hours: Balanced meal (carbs + protein + fats).
Rehydrate slowly with electrolytes (no alcohol yet!).
Keep eating small, frequent meals for the next 24–48 hours.
An Ironman is as much a nutritional challenge as a physical one. The best plan is one you’ve tested in training and can stick to under fatigue. Dial in your carbs, electrolytes, and hydration, and you’ll set yourself up for success.
Now go conquer that 140.6! 🚴♂️🏊♂️🏃♂️
Running a marathon is a massive physical feat—and without the right fueling strategy, even the most well-trained runners can hit the wall. Proper nutrition before, during, and after the race is just as important as your training plan. In this guide, we’ll break down exactly how to fuel for a marathon to maximize performance, avoid bonking, and finish strong.
During a marathon, your body burns 2,500–4,000+ calories, primarily from glycogen (stored carbs). Once glycogen runs low (usually around mile 18–20), fatigue sets in hard. Proper fueling helps:
✔ Delay muscle fatigue
✔ Prevent “the wall”
✔ Maintain mental focus
✔ Avoid stomach issues
Increase carb intake to 7–10g per kg of body weight (e.g., 350–500g/day for a 150lb runner).
Focus on complex carbs (pasta, rice, oatmeal, sweet potatoes) and reduce high-fiber foods to avoid GI distress.
Stay hydrated with electrolytes (sodium, potassium).
Eat a familiar, carb-heavy meal (e.g., pasta with light sauce, rice + lean protein).
Avoid excessive fat, fiber, or spicy foods that could upset your stomach.
300–500 calories from easy-to-digest carbs (toast with honey, banana, oatmeal).
Small protein/fat source (peanut butter, yogurt) if tolerated.
Hydrate well (16–20 oz water + electrolytes).
Caffeine (if you’re used to it) for an energy boost.
Start fueling early—don’t wait until you’re tired or thirsty.
Aim for 30–60g carbs/hour (more if you’re a faster runner).
Take small sips of water at aid stations (don’t chug!).
Practice in training! Never try new foods/drinks on race day.
Gels/Chews : Take with water to avoid stomach issues.
Example Fueling Plan:
Start line: 1 gel
Every 25/30mins: Energy Gel
Caffeine: Your last x2/3 Gels should be caffeine.
❌ Skipping early fueling → Bonking at mile 18
❌ Drinking too much water → Sloshing or hyponatremia
❌ Trying new gels/drinks → Stomach disaster
❌ Overloading on sugar → Energy crashes
❌ Forgetting electrolytes → Cramping
Your body needs fast carbs + protein to rebuild:
Within 30 minutes: Recovery drink, chocolate milk, or banana + protein bar.
Within 2 hours: Balanced meal (carbs + protein + healthy fats).
Rehydrate with electrolytes (coconut water, sports drink).
A smart fueling strategy can make or break your marathon. Test different foods and timing in long runs to find what works best. On race day, stick to your plan, stay consistent, and trust your training.
Now go crush those 26.2 miles! 🏃♂️💨
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