The 5K is the perfect entry point to racing - challenging enough to feel like an achievement, short enough that nutrition doesn't get complicated. Whether it's your first parkrun or you're chasing a PB, what you eat beforehand can help or hinder your performance.
The 5K Reality (The Science)
A 5K takes most runners 20-35 minutes. Your body stores approximately 2,000 calories of glycogen - enough for 90-120 minutes of running. For a 20-35 minute effort, you'll use roughly 20-30% of glycogen stores. Pre-race nutrition for a 5K is more about comfort and GI stability than energy loading - you have more than sufficient fuel already.
Pre-5K Timeline
The Night Before
Eat a normal, balanced dinner. Pasta, rice, or potatoes with some protein is fine. Don't stuff yourself or eat anything unusual. Avoid excessive alcohol - it affects sleep and hydration.
2-3 Hours Before Start
If the race is late morning or afternoon, have a light meal. Porridge, toast and eggs, or a small bowl of pasta. Nothing heavy or high-fat.
1-2 Hours Before
Small snack if hungry. Banana, toast with jam, or a few rice cakes. Keep it simple and familiar.
30-60 Minutes Before
Only eat if you need something. Half a banana or a small handful of dried fruit at most. Otherwise, just water.
Early Morning 5K (parkrun)
Most 5Ks start early - parkrun is 9am. Many runners wonder whether to eat at all.
Option 1: Don't eat. For a 5K, you have enough stored energy from yesterday. Just have water and maybe coffee. Many experienced runners race short distances on an empty stomach.
Option 2: Eat something small. If you feel better with food, wake up a bit earlier. Toast, banana, or a few bites of cereal 45-60 minutes before the start.
Experiment in training to find what works for you. Never try a new approach on race day.
Best Pre-5K Foods
Light, easily digestible, carb-focused:
What to Avoid Before a 5K
- High-fibre foods: All-bran, beans, raw vegetables - risk of urgent toilet needs
- Fatty foods: Full English, pastries, cheese - slow digestion, heavy feeling
- Large portions: Even good food in excess causes discomfort
- Coffee overdose: One is fine, three might make you jittery
- Anything new: Race day is not for experiments
- Excessive water: Stay hydrated but don't chug right before - you'll need the toilet
The Toilet Factor
Let's be honest - one of the biggest pre-5K concerns is needing the toilet mid-race. Running jiggles your insides, and adrenaline can speed things up.
- Aim to have a bowel movement before you leave home
- Coffee helps many people go - use this strategically
- Arrive early and use the facilities before the start
- If this is a recurring problem, avoid high-fibre foods the evening before
Hydration
For a 5K, you don't need to carry water or take drinks during the race. Just:
- Drink normally in the hours before
- Have a small glass of water 30 minutes before start
- Don't arrive dehydrated, but don't overdrink either
Your urine should be light yellow. Dark = drink more. Clear = you've probably overdone it.
The Golden Rule (Research-Backed)
Nothing new on race day. Studies on GI distress in runners consistently show that unfamiliar foods cause more problems than familiar ones, regardless of nutritional profile. Whatever you eat before a 5K should be something you've tested in training. The morning of your race is not the time to try that new natural energy bar or that breakfast you read about online. Stick with what you know works for your body.
After your 5K, proper recovery helps too. See our guide on what to eat after a 5K.
← Back to Running & Races
