Fuel Well, Run Strong

A Sports Nutritionist’s Guide to Eating and Drinking for Marathon Training

Training for a half or full marathon is one of the most rewarding challenges a runner can take on. But the kilometres alone aren’t enough. How you fuel and hydrate every day has a huge impact on how well you train, how you recover, and ultimately how you perform on race day.

Drawing on sports nutrition principles, this article breaks down what runners need to know about fuelling during marathon preparation, in simple practical terms you can start using today.

Why Nutrition Matters More Than You Think
Marathon training places a big demand on your body. Your muscles burn their reserves of carbohydrate every time you run; you lose fluid and electrolytes in sweat, especially in heat or humidity; and your muscles need regular protein to repair and adapt to training.

Getting your nutrition right helps you to train consistently, hit your pace targets, recover faster, reduce injury and illness risk, and arrive on race day energised rather than worn out.

Under-fuelling or under-hydrating, even unintentionally, can lead to fatigue, poor performance, mood changes, and increased risk of injury.

How Much Should You Eat When Marathon Training?

• Carbohydrate
  • Carbohydrate is your most important energy source as a runner. The amount you need depends on your training load. On regular training days you need around 5-7 g per kg of body weight. On heavier training days (especially if you have double sessions in a day) this goes up to 7-10 g per kg. For a 60 kg runner, this translates into 420-600g of carbohydrates in a day. Before your race, you need around 8-12 g per kg for 24-48 hours.
    
    Good choices include oats, pasta, rice, potatoes, bread, fruit, low-fat yoghurt, smoothies, sports drinks, gels and energy bars.
• Protein
  • You need protein for repair and recovery. Endurance runners should aim for 1.4-1.6 g protein per kg body weight per day to support muscle repair and adaptation. Spread this across the day:
    • 20-25g at breakfast, lunch and dinner
    • 10-20g in snacks or recovery drinks
  • Great sources include dairy, eggs, poultry, fish, tofu, beans, lentils and soya foods.
• Healthy Fats
  • Fat should make up 20-35% of your daily calories, focusing on healthy fats like olive oil, nuts, seeds, avocados and oily fish. Keep very high-fat meals away from intense sessions, as they slow digestion.

Matching Food to Training
One of the most helpful modern approaches in sports nutrition is tailoring your nutrition to your training days:

• Higher-carbohydrate days for long runs, race-pace sessions and back-to-back quality days.
• Lower-carbohydrate days for short easy recovery runs or short low-intensity sessions

Periodised fuelling prevents unnecessary fatigue and supports consistent training. Moreover, it helps in managing weight during training, while still fuelling adequately. This strategy should only be done with professional guidance.

Fuelling Your Training Runs

Before Your Run
Start your runs with good carbohydrate availability (1-4 g of carbohydrate per kg body weight consumed 1-4 hours before running).

Examples for a 60 kg runner:

• 3-4 hours before: 2 slices white toast with honey or jam
• 1 hour before: banana + yoghurt

Keep this meal low in fat and fibre to avoid stomach upset.

During Your Run
For runs longer than 60–90 minutes, taking in carbohydrate improves endurance and delays fatigue.

Suggested intake:

• 1–2 hours: around 30g per hour
• 2–3 hours: 30–60 g per hour
• >3 hours: 60–90 g per hour (if you’ve trained your gut)

This usually means:

• 1 gel every 40 minutes for half marathons
• 1 gel every 30-40 minutes for full marathons
• or a combination of sports drink + gels
• or sports drink + chews/soft bars

Train your gut during long runs to avoid issues on race day.

After Your Run
Think of the “3 Rs”:

1. Refuel: Replace carbohydrate
2. Repair: Include 20-25 g protein soon after running
3. Rehydrate: Replace lost fluids and electrolytes

Flavoured milk, chocolate milk, smoothies, whey protein with oats or banana, rice bowls with protein, and sandwiches with fruit are all excellent choices.

Fuelling and hydrating for marathon training isn’t complicated, but it does require consistency and planning. When you give your body the right nutrition, you’ll notice better energy, better training quality, better recovery, and better race-day performance.

Think of your nutrition as part of your training, not an add-on.

If you’ve enjoyed this article, watch out for the next article, where I will be delving into hydration, the use of supplements and carb-loading for full-marathons.