Trail running nutrition: before, during, and after

Nutrition is one of the three pillars of trail running, along with training and gear. Bad nutrition can cost you your race, while good planned nutrition can make the difference between struggling to finish and crossing the line strong. This complete guide covers everything: before, during, and after your trail effort.

Nutrition before the trail: The critical 72 hours

Nutrition doesn't start the day before. It starts 48-72 hours before your race. During this window, your main goal is to saturate your muscle and liver glycogen stores. You have two approaches: classic or scientific.

Classic approach: Progressive "carb-loading"

Three days before your race (D-3), start increasing your carb intake:

• D-3: Increase starches to 6-7 g/kg of body weight. If you weigh 70 kg, aim for 420-490 g carbs per day
• D-2: Increase to 7-8 g/kg, or 490-560 g for a 70 kg person
• D-1: Maintain 7 g/kg, but reduce fiber to limit GI distress

Prioritize simple, easy-to-digest starches: white pasta, white rice, white bread, peeled potatoes. Reduce fiber (whole vegetables) and bulky fats that slow digestion.

The pre-race meal: Simple and effective

Eat a starch-rich dinner 24 hours before the start. Example:

• 350 g white pasta (140 g cooked carbs)
• 150 g lean chicken (protein)
• Simple tomato sauce (low fat)
• A glass of white grape juice (30 g additional carbs)

Total: 170 g carbs, 30 g protein, low fiber and fat. Avoid heavy meals that would prevent sleep.

Race day breakfast: Critical timing

Race day breakfast depends on start time. Goal: have energy without digestive issues.

• 9 AM start: Breakfast at 6:30-7 AM (pasta, honey, banana) = 80-100 g carbs
• 2 PM start: Hearty breakfast at 9 AM (260 g starches, 40g protein) + snack at 12:30 PM (energy bar 30g carbs)
• 7 AM start: Light breakfast at 5 AM (50 g simple carbs) + gel 30 min before start (30 g carbs)

Timing: You need 3-4 hours to digest a full meal. If you have less than 2 hours, opt for liquid or paste carbs (smoothie, liquid porridge, gel).

Nutrition during the trail: "Fueling" in action

It's during the effort that your nutrition strategy makes the difference. Your muscle glycogen stores constantly decrease. Without fuel, "bonking" is guaranteed.

The 60-minute rule

For efforts under 60 minutes: plain water is enough. Your endogenous glycogen covers the effort.

For efforts of 60-90 minutes: 30-60 g carbs per hour. Start with 30-40 g/h in the final third.

For efforts over 90 minutes (20 km+): 60-90 g carbs per hour, increasing gradually.

Carb sources during effort

Three categories: gels, solid food, drinks. Each has advantages and disadvantages.

Gels: Standard format 35-50 g carbs per gel. Fast absorption (30 min). Convenient in races. Examples: Hammer Gel, GU Roctane, SIS Energy Gel. Dosing: 1 gel every 40-50 minutes for 60g/h. Always with water (250 ml).

Solid foods: Banana (25 g carbs), energy bar (40 g), dates (15 g per date), homemade energy bar (oats 50g + honey 20g = 70g carbs). Slower absorption (45-60 min) but better satiety. Excellent for ultras. Note: requires sufficient hydration.

Sports drinks: 6-8% carb drink: 100 ml = 6-8 g carbs. For 60 g/h, you need 750 ml/h. That's a lot. Advantage: hydration + carbs simultaneously. Disadvantage: volume to carry.

Practical fueling strategy for 20 km (2h30-3h)

Use this timing:

• T + 30 min: 1 gel (30 g carbs) + 200 ml water
• T + 70 min: 1 gel + 1 energy bar (70 g carbs) + 300 ml water
• T + 110 min: 1 gel (30 g carbs) + 200 ml water (if you're near the end)

Total: 130 g carbs over 2h50, or 45 g/h. Test this plan in training 3-4 times before the race!

The often-forgotten electrolyte

For efforts over 90 minutes, you lose sodium through sweat. Without sodium, you get cramping, potential hyponatremia, and poor carb absorption.

Minimum dosing: 500-700 mg sodium per hour. Options:

• Standard sports drink: 400-600 mg/L
• Effervescent tablet (SaltStick, Liquid IV): 300-500 mg per dose
• Gels with electrolytes (Hammer Gel Caffeine): 300 mg/gel
• Salted pretzels or peanuts: 200 mg per handful

Hydration: How much to drink?

Simple rule: drink 400-800 ml per hour, depending on weight and heat. More precisely:

• Cool weather (< 15°C): 400-500 ml/h
• Moderate weather (15-20°C): 600-700 ml/h
• Hot weather (> 20°C): 700-800 ml/h, max 1L/h

Drinking more than 1L/h without sodium risks hyponatremia. Remember: you're losing sodium, not just water.

Nutrition after the trail: The critical 30-minute window

The first 30-60 minutes after effort are critical. Your body is "ready" to absorb nutrients to recharge stores and repair muscles. You have an anabolic window.

Immediate recovery meal (30 min after)

A carbs:protein ratio of 3:1 or 4:1 is optimal. Examples:

• Milkshake: 300 ml milk + 50g oat flakes + 1 banana + 20g protein powder = 60g carbs, 25g protein
• Greek yogurt: 300 ml Greek yogurt + 100g granola + 1 apple = 75g carbs, 20g protein
• Sandwich: White bread + 50g ham + cheese = 50g carbs, 25g protein
• Simple pasta: 200g cooked pasta + 150g white fish = 60g carbs, 30g protein

Consume this meal within 30-45 minutes after finishing. Yes, even if you're not hungry. It's scientifically proven that this speeds up recovery by 20-30%.

The following 2-4 hours

After your quick recovery meal, prioritize hydration and carb- and protein-rich food:

• Keep drinking: water + electrolytes (500 mg sodium/L) to compensate for fluid loss
• Have a full meal 2-3 hours after: starches, protein, vegetables
• Protein snack: yogurt, cottage cheese, nuts

The next 24 hours: Continue high carb intake (5-7 g/kg of body weight) to fully replenish depleted glycogen stores. For a 70 kg person, this means 350-490 g carbs spread throughout the day.

Common nutrition mistakes in trail

Mistake 1: Testing a new product on race day

This is the #1 cause of GI distress. You discover your stomach hates that gel at km 15. Test EVERYTHING in training, at least 3 times.

Mistake 2: Ignoring the recovery window

"I'll eat when I'm done." Wrong. Your recovery starts now. Eat something sweet and protein-rich within 30 minutes.

Mistake 3: Drinking only water during long effort

You finish hypoglycemic despite a 3L hydration pack. Water alone isn't enough after 90 minutes. You need carbs AND electrolytes.

Mistake 4: Excessive carb-loading

You double your usual intake. Result: bloating, heaviness, diarrhea at km 10. Increase gradually by 20-30%, not 100%.

Mistake 5: Forgetting to test gastric acidity

Some gels are very acidic (citrus) and cause nausea. Test first. Prefer neutral or mild fruit flavors (apple, berry).

Complete nutrition plan for a 20 km trail

Day -1

• Breakfast: 150g pasta + 30g honey + 200ml grape juice
• Lunch: 250g chicken + 250g white rice
• Snack: 2 energy bars
• Dinner: 350g pasta + tomato sauce + 150g fish + glass white juice

Race day (9 AM start)

• 6:30 AM: 200g pasta + 30g honey + 200ml grape juice
• 8:45 AM: 1 gel + 200ml water
• 9:00 AM: Start
• Km 5 (T+45 min): 1 gel + 250ml water
• Km 12 (T+100 min): 1 bar + 1 gel + 300ml sports drink
• Km 18 (T+150 min): 1 gel + 200ml water
• Finish (T+170 min): Immediately: protein milkshake (60g carbs, 25g protein)
• 1h after: Meal: pasta + fish + tomatoes

Conclusion: Nutrition, the third pillar

Good trail running nutrition is like a race car with quality fuel. Without it, you'll break down. With it, you have the energy to finish strong.

The key: plan, test, adapt. Every body is different. Your friend might run 20 km on 1 gel and 500ml water. You might need 150g carbs. Discover your personal formula in training, and you'll cross the finish line with a smile.