Fuelling for a Half-Marathon: Your Nutrition & Hydration Plan
If you’re preparing for a half-marathon, getting your nutrition and hydration right is just as important as your training. To perform at your best and keep fatigue at bay, it’s essential to have a plan in place — not just for race day, but also in the weeks leading up to it.
Carbohydrate is your body’s preferred fuel during long runs. However, glycogen stores are limited — typically enough to last around 90 minutes at race pace. This means starting the race with full glycogen stores and topping up during the event will help maintain your pace and delay fatigue. Everyone’s needs vary, but the following guidelines can help you create a plan that works for you.
Use Training Runs to Practise Fuel Strategies
Your long runs are the perfect opportunity to test different fuelling and hydration strategies. Start consuming carbohydrate 30–45 minutes into your run to help stabilise blood glucose levels and provide your muscles with a steady energy supply.
For sessions lasting 1–2 hours, aim for around 30g of carbohydrate per hour. This might take some getting used to, especially if you usually run on an empty stomach, but training your gut to tolerate food and fluid on the move can make a big difference on race day.
To reduce the risk of gastrointestinal issues, begin with small amounts and build up gradually over time. By doing this, your gut will adapt and become more efficient at absorbing fuel while you run.
Once you've identified foods and drinks that work well for you, replicate your planned race-day strategy on a few long runs. Run at the same time of day as your race and practise using the same fuels at the same intervals. Don’t forget to practise drinking from bottles or cups — it’s a skill worth developing.
Trial and Error in the Weeks Before
Now is the time to experiment with a variety of carbohydrate sources. Sports drinks, gels and energy bars are convenient and rapidly absorbed, while whole foods like bananas, oat bars or dried fruit may be gentler on your stomach at the start of longer runs.
Many runners find that a mix of both works best — whole foods early on, with more easily digestible options later. Pay attention to how your body responds and stick with what feels right.
Leading Up to Race Day
While full carbohydrate loading isn’t usually needed for a half-marathon, it’s still important to line up with well-stocked glycogen stores. Begin tapering your training a few days before the event and increase your carbohydrate intake during the final 24–48 hours.
Aim to include larger portions of carbohydrate-rich foods — such as pasta, oats, potatoes, rice and bread — with each meal, along with additional snacks like bananas, energy bars or bagels.
The Day Before the Race
The food you eat the day before will be converted into glycogen and stored in your muscles and liver, ready for race day. Focus on consuming most of your carbohydrates earlier in the day rather than overloading with a large evening meal, which may leave you feeling heavy or bloated.
Avoid foods that could upset your stomach, especially if you’re prone to digestive issues. While spicy or high-fibre meals are usually fine for some, others may benefit from steering clear in the final 24 hours.
Race Morning
Eat a high-carbohydrate, low-fat breakfast 2–4 hours before the start. This helps replenish liver glycogen and keeps your blood sugar stable during the race. Good options include porridge, muesli, toast or bagels with jam or honey.
Hydration is just as important. Aim to drink around 5–10 ml of fluid per kilogram of body weight in the 4 hours before the start. After that, sip as needed — drinking too much can lead to discomfort or extra pit stops.
Some runners like to take in 20–30g of fast-digesting carbohydrate 15–30 minutes before the start — a banana, a gel, or a sports drink are good choices. But listen to your body: if you don’t feel like eating, don’t force it.
During the Race
Start fuelling around 30–45 minutes in — the same way you did during your training runs. Stick with products you’ve tested. Carry your own fuel if you can and check in advance where water stations are located on the course.
Most runners will need between 400–800ml of fluid per hour, depending on sweat rate, weather, and individual needs. Again, practise this in training so you know what works best for you.
After the Race: Refuel and Recover
Rehydration should be your first priority post-race. Water, electrolyte drinks or recovery formulas will all help replace lost fluid and speed up recovery.
Next, focus on getting carbohydrate and protein in your recovery meal to replenish glycogen stores and support muscle repair. Include colourful fruit and vegetables for their antioxidant properties. Good choices include a recovery smoothie, yogurt with granola and berries, or a hearty stir-fry with noodles and tofu.
Final Thoughts: Personalise Your Plan
Your nutrition strategy should be as individual as your training plan. Practise fuelling during training, identify what works for you, and approach race day with a plan you trust.
Race-Day Checklist:
Start fully fuelled and hydrated
Bring your own fuel (and know how to carry it)
Stick to what you’ve practised
Be flexible — adapt if conditions change
Consider caffeine if you’ve trained with it and know it benefits you
By taking the time to plan, practise and personalise your fuelling strategy, you’ll give yourself the best chance of running strong from start to finish.