How to fuel a Marathon: Dietitian style

Dietitian Katherine Kimber talks marathon prep. See a dietitian’s meal plan for the lead up to a race!

If I were given money every time I heard “I bet you have the perfect diet” I would certainly be a rich lady. Fuelling for a marathon is certainly not easy (even for a Dietitian) and varies for each individual. I love running and any sort of endurance sport that pushes your body to its limits. I have run a couple of marathons (3hrs 37minutes being my best), a whole load of half marathons and some long distance trial running in the peak district. I would like to share with you my knowledge and personal experiences to help better fuel your marathon day the most natural way…

3-5 days lead up:

  • I drink plenty – Being well hydrated is key. The average daily requirement for active individuals is around 2.7-3.7Litres (any drink counts towards this except alcohol).
  • I eat a balanced diet with regular meals – getting my five a day, adequate protein, low fat dairy and high fibre, low glycaemic index starchy foods.

24-hour pre race:

Breakfast – porridge & banana plus 2 slices of wholegrain bread with jam.
Lunch – wholegrain pasta with a plain tomato based sauce & simple side salad.
Dinner – the same as lunch but smaller portion. I try to have my larger meal in the afternoon and eat just to fill the hunger gap in the evening. I feel I sleep better and do not have that fullness feeling the morning of race day.
Drink, drink & drink – I sometimes use fresh juice diluted with water and a pinch of salt to ensure I am as hydrated a possible.
Snacks: Fruit, yoghurt, crackers with hummus.

The big day:

I have breakfast as early as possible, ideally 3-4 hours before the start so I don’t run on a full stomach. Having1.8g carbohydrate/lb of body weight for this meal is ideal. That’s around 220g carbohydrates for me, which I achieve through 50g porridge, 300ml milk, 1 tbsp honey, 30g raisins, 1 banana, 2 slices of bread with jam. I would also ensure I drink approximately ½ Litre of water 90-120 minutes prior to exercise (including of course a coffee for that extra caffeine boost!).

Just before the start…

I top up on 1 small banana 30-40 minutes before I set off. I would also take on around ¼ litre of water half an hour before the event, but I would try and avoid drinking after this as often just means needing to find a toilet while in the starting pen!

During the run:

We can generally store enough energy in muscles for about 20 miles. After this often people ‘hit the wall’. This is why fuelling on carbohydrates early on in the run is important. I would aim to take on board 30-60g/hour of carbohydrates in the form of something easy to chew or digest. I would often choose foods such as dried dates, figs and cherries. One dried date (around 24g) contains 17g of carbohydrate. Three in an hour for example would provide you with the right amount of carbohydrate, but I would certainly try these out before the big day! I would also aim to drink 100 – 200mls of fluid every 15 minutes.

After the event:

I often don’t feel like eating after a marathon. I actually feel a little sick. It’s really important however to continue to drink and replace those glycogen stores. I would have a sandwich, or a small bowl of pasta, and generally try to take on some carbohydrate-based food over the next 4 hours.

A few common questions

Should I increase my carbohydrate intake?

Tapering training and increasing your carbohydrate intake for 3-5 days prior to the event is now suggested. This doesn’t necessarily mean going crazy on the pasta, but altering your ratios of carbohydrate, fat and protein. For example fill ½ of your plate with starch based carbohydrate foods rather than ¼ usually suggested for a balanced diet.

Do we really need pasta before the event?
The ‘ideal’ pre-marathon meal should be:
* CHO based
* Low in fat
* Contain some but not excessive protein
* Avoid excess fibre

Now to translate that into actual food, a good main would include 100g chicken/other lean meat or beans, with wholemeal pasta or brown rice and a tomato based sauce with salad. For pudding, choosing fruit or a fruit crumble and custard for a higher energy option would be ideal.

I’ve heard that eating straight before exercise can inhibit performance?

It is sometimes thought best not to take on board carbohydrate in the 30-60 minutes before exercise as this causes insulin release resulting in a lack of sugar in the blood during the first 15-30 minutes of exercise. Personally I feel the effect of this depends on the intensity of exercise and for a steady tempo marathon, having a snack such as a banana goes does well for me. The research into this is mixed, but generally concludes having a carbohydrate snack before exercise will not negatively affect performance.

Overall, the key to fuelling naturally during a long run is to experiment and find what works for your body. I recommend you try new fuel types during shorter runs, which is anything less than an hour. That way, you can consume the new fuel about halfway through and see how your body reacts without having to suffer through a long run.