How to use nutrition to have your best marathon performance

Nutrition is a key piece of your success in the marathon. Often just fixing some of the mistakes that a lot of marathon runners make can improve your times, increase performance, and reduce your potential for injury.

Here are some of the biggest mistakes that marathon runners frequently make:

Not eating enough calories – This is surprisingly common (A recent study about Boston Marathon finishers estimates that almost 40% of women and 20% of men were likely in Low Energy Availibility1). Marathon training takes a lot of energy for your body and it’s easy to underfuel. Insufficient calorie intake during marathon training also substantially increases the risk of injury. As your mileage increases, make sure that you also increasing your calorie intake, even on rest days. This may require a little extra planning and making sure you have snacks available throughout the day.

Being scared of carbs- During marathon training, carbs are your friend. You should be increasing the proportion of carbs in your diet to account for the greater intensity of training. Carbohydrates are the main source of fuel for the majority of your runs. During a marathon training block, you are constantly using and replenishing your body’s stores. This is particularly crucial around long runs.

Not fueling before a workout – Especially critical for morning runners, taking in some type of carbs before your run is important not just for performance and hitting your targets, but also for recovery. Remember, you’re not just planning for this run, you need to be ready to run again throughout the weeks to come.

Not fueling during your run – Fueling during a longer run improves performance, also increases recovery, and allows you to train your body for race day as well. You may also want to fuel for shorter runs than you would during other training blocks, mainly those more intense sessions. Fueling during a run gives you the opportunity to practice for race day and acclimate your body to using more carbohydrates per hour (60-90g) which has been shown to improve performance2.

Neglecting your nutrition can undermine even the best training cycle. Incorporating proper fueling is a foundational piece of success in your racing.

Bottom line: If you’re looking to hit PRs, enjoy your racing, and stay injury free, fuel enough and fuel often.

1doi: 10.1136/bjsports-2024-108181

2doi: 10.1136/bjsports-2024-108181