Running on carbs: what you need to know

Carbohydrates are one of the most important foods for your body. They help power your muscles, aid their recovery after exercise and provide the energy you need to perform at your best.

But knowing how much to eat (especially when you’re training) can feel a little confusing.

Your body breaks carbohydrates down into glucose, which is used for energy. Any extra glucose is stored as glycogen in your muscles and liver, which your body uses when it needs a boost of energy, like during exercise.

"When you're running, especially during longer distances or higher intensity sessions, your body relies heavily on glycogen stores for sustained pace and performance," says Bupa Dietitian, Ahmad Hazim.

“Once those stores start running low, your energy drops and you’re at increased risk of fatigue and injury.”

Carbohydrates might provide the main fuel for your body, but they're only one part of the picture.

Protein helps repair and rebuild muscles after training, while healthy fats support hormone production, brain function and provide a longer-lasting source of energy.

Rather than focusing on one nutrient, aim for balance across your meals.

A balanced meal might include:¹

• Wholegrain pasta, rice or potatoes for carbohydrates
• Lean meat, fish, eggs, tofu or legumes for protein
• Avocado, nuts, seeds or olive oil for healthy fats
• Plenty of colourful fruits and vegetables

Eating more carbs and reducing training in the lead-up to race day can help.

“Going into a marathon with full glycogen stores means your muscles have the fuel they need to keep working hard,” says Ahmad

“Carb loading can help you hold your pace for longer, tackle those tough final kilometres and finish stronger.”

• Aim to eat 10–12 g of carbohydrate per kilogram of body weight per day for 36–48 hours before race day to help maximise glycogen stores.²
• Eat low‑fibre, high‑carbohydrate meals, sports drinks, white rice, pasta, bread and frequent snacks to reach the required target.

What you eat before training depends on how long and hard you will be running.

For shorter, easy runs, you may not need much food beforehand.

For longer or higher intensity sessions, eating more can help top up your glycogen stores.

Good pre-run options include:

• A banana
• Large wrap with tuna and salad
• Toast with peanut butter and honey
• Rice with some chicken and veg
• Yoghurt with fruit and muesli.

Everyone digests food differently, so use your training runs to find out what works for you.

For runs lasting less than around an hour, it’s likely that you’ll only need water.

For longer runs, (around 90 minutes or more), your body may need a little extra fuel along the way.

Signs that you may need to eat:

• Your legs feel heavier or harder to move
• You struggle to maintain your usual pace
• You feel mentally drained and less focused
• You feel hungry, thirsty or nauseous

Current sports nutrition guidelines recommend eating around:²

• 30-60 g carbohydrates per hour for runs lasting 1-2.5 hours.
• Up to 90 g per hour for events lasting longer than 2.5 hours (with practice).

Foods and drinks that are easy to consume on the go include:

• Sports drinks
• Soft lollies
• Bananas
• Dried fruit
• Energy gels

Energy gels are one of the easiest ways to top up carbs during a long run,” says Ahmad. “They’re lightweight, easy to carry and provide fuel your body can quickly use.

The meal after your run is just as important as the one before it.

Eating carbohydrates refills your energy stores, while protein helps your muscles repair and recover.

Try to eat within an hour after longer or harder training sessions.

Some simple recovery meals include:

• Chicken and rice
• Pasta
• Eggs on wholegrain toast
• Greek yoghurt with fruit and granola
• A smoothie made with milk, fruit and oats

Don't forget to top up your fluids too, especially after hot or sweaty runs.