How To Get Your Marathon Nutrition Right

An expert guide to marathon nutrition

Author: Laura Hilton

Read Time:   |  April 21, 2022

Getting your marathon nutrition right is important – we get an expert opinion from nutritionist Laura Hilton

Marathon training places huge demands on your body and it is therefore hugely important to tailor your diet to ensure your body has all of the nourishment it needs to keep you feeling healthy, energised and strong – particularly as you up the mileage.

First marathon? Make sure you’ve got your marathon training plan down.

Need more training? Here’s our marathon base training guide.

Do I need to eat more if I’m training for a marathon?

If you have your sights set on running a marathon, then congratulations for even considering a challenge that most people wouldn’t entertain. Preparing to comfortably run each step of the 26.2 miles not only requires planning and sticking to a training schedule, but also some thought about the nutritional demands of your running. Many runners wonder if they need to eat more when they start training for a marathon, but the truth is that it depends. It depends on your activity level and how much you eat before you start training, and any bodyweight goals you might have.

Energy balance explained

The term “energy balance” relates to the amount of calories you consume versus the amount that you burn. If you burn the same amount as you consume your bodyweight will stay the same. If you burn more than you consume you will lose bodyweight. If you burn less than you consume then you will gain bodyweight. In order to know if you need to increase your nutritional intake when you embark on marathon training you need to know if you are currently in an energy deficit, balance or surplus. To know if you are in an energy deficit, balance or surplus you will need to monitor your bodyweight. If it is stable you are in energy balance, if it is decreasing you will be in an energy deficit, whereas if it is increasing you in an energy surplus.

Are you trying to change your weight?

The next thing to consider is if you have any bodyweight goals. It’s also important to think about your current level of activity, and if training for a marathon is going to see a massive change in it or not. If your activity levels won’t change that much then you would most likely only need to eat more if you wish to gain weight. If you are not currently doing any training at all and want to either maintain energy balance or gain weight then you most definitely will need to eat more to support your increased activity levels. If you wish to lose weight then you may not need to increase your nutritional intake at all, but be careful to refuel sensibly throughout your training.

Be aware of REDs

If athletes are in an energy deficiency a lot of the time, then they are in danger of developing a condition known as Relative Energy Deficiency in Sport (RED-S). This can lead to numerous problems including fatigue, weakened bones, hair loss and fertility issues, amongst other things. It is therefore really important that you do not spend long periods of time in an energy deficit, which you can monitor by keeping an eye on your bodyweight. If it is continually decreasing this is a sign that you are not eating enough and therefore in danger of developing RED-S.

Whether or not you need to increase your nutritional intake when training for a marathon depends on your current energy balance and any bodyweight goals you may have. Think about both of these things and you will then know if you do indeed need to increase your nutritional intake while you are training for a marathon.

4 marathon nutrition essentials:

  1. Carbohydrates: The amount of carbohydrate you should be eating will depend upon the duration and intensity of the exercise you are doing, but it’s essential that you get enough carbs.
  2. Healthy fats: Monounsaturated or polyunsaturated fats are a great fuel source. Try and have two or three portions a day: we’re talking avocados, olive oil and nuts.
  3. Protein: Protein is important when you are training for a marathon as it will help your muscles to make training adaptations – recovering and repairing after runs and ultimately becoming stronger. Here’s how much protein you should be eating as a female runner.
  4. Hydration: Ensure you drink enough to replace lost fluids and use your urine colour as a way of checking your hydration status at the end of a run. Your urine should be a light straw colour; too dark and you’re dehydrated, but too light and you’re drinking too much!

Written by

Laura Hilton

Laura Hilton

Nutritionist, personal trainer and mum of three Laura loves running in the countryside with her dog and has taken on numerous marathons

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