Everything you need to know to fuel a successful 13.1-mile race day.

Don’t know what to eat before a half marathon?

If you get your half marathon nutrition correct, you’ll run a better race, avoid gastrointestinal problems, and feel your best when it matters most.

I spoke to Amy Goblirsch, a registered dietitian and qualified run coach, for a deep dive on what you should eat before a half marathon.

Continue reading to find out what to before race day, including a breakdown of meals and meal timing to prepare you for race day.

What you will learn:

  • What to eat before a half marathon for optimal performance

  • What to eat the week before and the days leading up to the race

  • Whether you should use energy gels during a half marathon

What should you eat before a half marathon?

Many runners realise they should carb-load before a marathon. It ensures your glycogen stores — this is your primary fuel source — are topped up so you have the energy needed to perform your best.

But fewer runners know you should also eat more carbohydrates leading up to a half marathon. 

“Carb loading is a key aspect of race week, involving increased carbohydrate intake for 1-3 days before the race,” says Goblirsch.

She explains the number of days needed for carb loading depends on your expected finish time, with recommendations ranging from 10 to 12 grams of carbohydrates per kilogram of body weight.

To increase your carbs, add more potatoes, bread, pasta, or rice. You can also add liquid carbohydrates, making hitting the increased carbohydrate needs much easier. Endurance drinks, fruit juice like orange juice, or lemonade are good options.

For snacks, she recommends pretzels, fruit, graham crackers, or her personal favourite, pop tarts.

What to eat the week before a half marathon

In the week before a half marathon, you don’t need to change your diet too much. 

Your nutrition will look similar to that of the rest of your training block. Although 1 to 3 days before the race, increase your carb intake, as previously mentioned.

“In the days before carb loading, focus on a high-carbohydrate, moderate-protein, and low-fat diet. Although fibre is essential, it’s best to limit it to avoid gastrointestinal issues on race day. It’s best to stick to foods you are familiar with, says Goblirsch.” 

What to eat the day before a half marathon

The day before a half marathon, eat plenty of carbohydrates, prioritising foods like potatoes, rice, and pasta.

You don’t need to overeat, but ensure your glycogen stores are full to help you perform your best on race day.

Also, drink plenty of water and use electrolyte drinks to reduce the risk of dehydration. Your body also needs additional hydration during carb loading because the storage of glycogen in your muscles requires water.

If you’re not properly hydrated and drinking enough water, you’re not carb-loading properly.

What to eat the morning of a half marathon

“Pre-race breakfast should be consumed 2-4 hours before the start to allow time for digestion. Aim for at least 75 grams of carbohydrates at this meal. Sipping on water or an electrolyte drink can help with hydration status.

An example breakfast may include a bagel with peanut butter and jelly, a banana, and an SLT07 hydration tablet with 450 to 500 ml of water for added electrolytes and proper hydration," suggests Goblirsch.

For a pre-race snack, consider an energy like GEL30 for quick-to-digest carbs.

Also, drinking caffeine in the morning can help with bowel movements to avoid anything unexpected during your race. But if you're particularly caffeine sensitive, it's best to avoid this.

What to eat during a half marathon

While this blog post is about what to eat before a half marathon, if you want to run your best, you need carbohydrates during the race.

Consume 30 to 60 g of carbohydrates per hour.

That’s two GEL30 Dual-Carb Energy Gels per hour.

If your estimated finishing time is 4 hours, that’s a total of four energy gels.

Read our how many gels for a half marathon post for more advice.

What to eat after a half marathon

After you have finished your race, try and get plenty of carbs and protein (lean protein if possible) to refuel your glycogen stores and kickstart the recovery process.

A recovery bar, like BAR50, contains 45g of carbs and 15g of protein to help contribute to overall recovery.

It’s also essential to take on more fluids to stay hydrated.

Drink water often after your race and in the days following.

You may also find it useful to add electrolytes, especially if it was a hot or humid race, to help restore electrolyte balance and achieve proper hydration. It will also help support your recovery.

Should I take gels for a half marathon?

A lot of runners use energy gels because they are easy to use and provide a quick release of carbs. Unlike other foods, they easily fit into your shorts pockets or hydration vest.

If you haven’t used energy gels before, I suggest using them in your weekly long run to practise. 

It will give you a feel for how to fuel your body — and at what interval — and see how your body responds to foods like energy gels. On the off chance that they disagree with you, you don’t want to find this out for the first time 9 miles and 3 energy gels into a half marathon. 

What not to do before a half marathon?

There are a few things you should generally avoid before a half marathon when it comes to your nutrition, like:

  • Avoid eating too much fibre as this may cause gastrointestinal upset

  • Don’t eat new foods in the days leading up to a half marathon

  • Avoid eating processed or spicy foods

  • Trying energy gels, chews, or sweets for the first time during your race

  • Eating too soon to the race start and now allowing time for proper digestion 

Key takeaways

  • Increase your carbohydrate intake 1-3 days before your half marathon

  • Add more potatoes, bread, pasta, or rice to increase your carbohydrate intake

  • Prioritise a high-carb, moderate-protein and low-fat diet leading up to race day

  • Limit fibre intake to prevent gastrointestinal issues

  • Eat at least 75g of carbs 2 to 4 hours before the race start

  • Consume 30 to 60g of carbs during the race to ensure you have enough energy to perform your best and avoid bonking 

  • Drink plenty of water in the days leading up to race day (and consider electrolytes the morning before your race)

FAQs

Is a banana good before a half marathon?

A banana can be a good source of quick-acting carbs 20-45 minutes before a half marathon. But you would ideally eat breakfast with plenty of carbs 2 to 4 hours before running to ensure your glycogen stores are full.

Are energy gels needed for a half marathon?

Energy gels are useful for a half marathon because they give you a quick source of reliable and consistent energy. Most athletes prefer gels for their simplicity. But they are not essential. You can eat other foods if you prefer.

Is running on an empty stomach good?

Running on an empty stomach is okay, but avoid this if doing a long run or before a half marathon. You want full glycogen stores before both of these to perform at your best.