Why Marathon Nutrition Is a Make-or-Break Factor
Running a marathon burns through an enormous amount of energy — somewhere in the region of 2,500–3,500 calories depending on your pace and body size. Your body can only store enough glycogen (your primary fuel source) for roughly 18–20 miles. That's the science behind "hitting the wall." The good news? Smart fuelling can prevent it entirely.
The Three Phases of Marathon Nutrition
Phase 1: The Week Before (Carb Loading)
In the two to three days before your race, gradually increase your carbohydrate intake to top up your glycogen stores. This doesn't mean eating mountains of pasta — it means shifting your diet so carbs make up a higher proportion of your calories.
- Focus on easily digestible carbs: white rice, pasta, bread, potatoes, bananas
- Reduce high-fibre foods to avoid GI issues on race day
- Stay well hydrated but don't overdo it — plain water plus electrolytes is ideal
- Avoid introducing new foods you haven't eaten before
Phase 2: Race Day Morning
Your pre-race meal is critical. Aim to eat 2–3 hours before the start to allow full digestion.
- Good options: Porridge with banana, white toast with peanut butter and honey, a bagel with jam
- Target around 60–90g of carbohydrates
- Keep fat and fibre low — they slow digestion
- Sip water steadily but avoid chugging large amounts
If you're a nervous eater, a sports drink or energy drink can top up carbs without requiring solid food.
Phase 3: During the Race
This is where most runners go wrong. You need to start fuelling early and consistently — don't wait until you feel tired or hungry, because by then it's too late.
| Mile Marker | Action |
|---|---|
| Miles 1–5 | Settle into pace, sip water at aid stations |
| Mile 6 | Take your first gel or chew (with water, not a sports drink) |
| Miles 9–10 | Second gel/fuel; begin taking electrolyte drinks |
| Miles 13–14 | Third gel; assess energy levels |
| Miles 17–18 | Fourth gel; this is the critical zone — stay on top of fuel |
| Mile 20+ | Final gel if needed; focus on reaching the finish |
Choosing Your Fuel
The market offers plenty of options — the key is to practise in training with whatever you plan to use on race day. Never try a new product on race morning.
- Energy gels: Fast-acting, portable, and widely available at races. Some runners find them hard on the stomach — test them on long runs first.
- Chews and blocks: A good alternative if gels feel too slimy. Slightly slower to digest.
- Real food: Dates, banana pieces, rice cakes — popular with ultrarunners and those who struggle with processed products.
- Sports drinks: Provide both carbs and electrolytes simultaneously, but can cause GI issues in large amounts.
Hydration: How Much Is Enough?
Over-hydration is as dangerous as dehydration. A general rule: drink to thirst, not to a rigid schedule. Aim for small sips at every aid station rather than large gulps. In warm conditions, prioritise electrolyte drinks to replace sodium lost through sweat.
Post-Race Recovery Nutrition
Within 30–60 minutes of finishing, eat a meal or snack containing both carbohydrates and protein to kick-start recovery. Chocolate milk, a recovery shake, or a proper meal all work well. Rehydrate steadily over the hours that follow.
Remember: train your gut just like you train your legs. Practice your nutrition strategy on every long run.