Time to Read

6 Minutes

Post Talking Points

  • Carb Loading Advice
  • When to Eat Throughout your Training Program
  • What to Eat
  • Recovery Plan

Food is Fuel

Physical training for a marathon or any endurance race is normally thoroughly planned out, with training regimes starting months prior to the race.

How much thought do we give to our diets though?

Often, only the 24 hours before the race are planned even though studies show that our longer term diets impact our performance.

Many studies show that a high carbohydrate diet and subsequent high muscle glycogen (stored carbs) results in enhanced short- and long-term exercise performance.

So, diet is key and especially carbohydrates!

Follow our tips below for a stronger body with plenty of fuel for racing.

The How, When And What Of Eating

Use this as guidance. Try things out for yourself and see what works best for your body.  

I would carb load for a few days before a marathon, but some don't carb load at all.

Using evidence-based research and real-life experience, here is some diet plan guidance from 4 weeks pre race to 24 hours post race.


Maybe two of the most spoken words when marathon runners discuss their training and pre-race plans, ‘carb loading’.

Get it right and you can increase time to exhaustion by at least 20%. Get it wrong and you could spend more time in the porta loos than on the road.

The average body has enough muscle glycogen to keep the body running for approximately 90 minutes. Whereas, the average time taken to complete a marathon ranges from 3.5 to 4.5 hours.

Carb loading helps extend the 90 minutes.

Topped up with carbs during the run, you can last much longer.

The recommended carbohydrate intake for carb loading is 10-12g per kg of body weight per 24 hours, 3 to 4 days prior to your event.

Try to include wholegrains and fruits in this amount to ensure you don't become clogged up, tired and uncomfortable.




Week 1 of the plan should be your normal diet - balanced fat, protein and carbs. You should be maintaining weight here and ensuring you account for calories lost from your long training runs.

Recommended carbohydrate intake for regular exercisers is 5-7g per kg of body weight per day.

This is also the perfect time to start practising your pre, during and post race fuelling.

Depending on your training plan, you’re likely to be doing some of your longest runs in the early part of this block, before tapering exercise altogether closer to the big day. So, start to test out carb loading the night before a long run, see what sorts of breakfast/pre run snacks you and your stomach can handle, and whether you perform best using gels, bars or just sweets during a run.

Practice your breakfast routine and try out eating and drinking when running.

Some people's stomachs do not agree with certain gels so make sure you try out a couple of brands, and if possible, find out what kind of gels they will be handing out during the event to see if they work for you.

What may be optimal for your performance may be less or more than the recommended guidance. So make sure you get to know your body and digestive system in this time.


You'll be tapering your runs now and giving your body time to rest, recover and prepare (muscles allowed to store glycogen).

Begin carb loading consistently for 3-4 days before the event using the tried strategy you have developed over the past 3 + weeks.


Your evening meal and your breakfast are very important!

Ensure your evening meal is tried and tested. A lot of people avoid eating too much fatty or spicy foods 24h before a race, but if you find you are fine with a big cheese and chilli pizza, then indulge!

See the ‘What’ below for meal suggestions and guidance.  

Try to maintain your usual breakfast routine (even if it is 3 or 4 hours earlier than normal!).

You should know by now how soon before exercise your body can handle food, but typically, a meal should be 2-4 hours pre exercise, snacks can be up to 1 hour before.

There is mixed evidence on whether high or low GI (glycaemic index) should be consumed prior to exercise. Evidence exists in support of low GI foods and shows positive effects on performance.

Benefits may be due to increased fat oxidation and a sustained carbohydrate source throughout endurance exercise. However, other research shows little or no benefit when compared to high GI foods.

What remains true though, is that there is less risk with low GI foods than with high, as if you get the timing wrong when consuming a high GI meal, you could end up starting the race on a sugar low. The safest strategy is to consume a low GI breakfast and top up with high GI snacks during the race.


Full refuelling after an endurance race can take up to 7 days. In this time, muscles will need to repair themselves using protein and carbohydrates.

During the 6 hours post race, glycogen replenishment is higher than normal. So consuming carbohydrates in this time will help speed up recovery. Research has shown that consuming carbohydrate (0.8g/kg BW/hour) with protein (0.2-0.4g/kg BW/hour) can improve recovery. This is because it creates a greater output of insulin and so blunts the rise in cortisol and promotes glycogen and protein synthesis (replenishes muscle glycogen and repairs damaged muscles).


Evening Before (10 to 12h to go) providing 150 - 200g carbohydrate

  • 170g Pasta, tuna, pesto, tomatoes and green beans plus half garlic bread baguette
  • 350g potatoes (sweet/white, chipped/baked etc), vegetarian sausages, 150g sweet corn, 100g broccoli. Supper/dessert, 2 flapjacks and an orange or banana
  • 170g pasta, chickpeas & butternut squash, tomatoes and carrots. Dessert, 150g mango. Supper/pre-bed snack, toast and peanut butter

Morning (2 to 4h to go)

  • Whole grain cereal with fruit, milk or yogurt
  • Porridge with milk
  • Sandwich/bagel with chicken/fish/egg/peanut butter plus salad

Snacks (1 to 2h to go)

  • Fresh fruit
  • Energy bar
  • Bread with honey or jam

After exercise, providing 60-90g carbohydrate and 15-25g protein

  • Two bananas and 500ml of semi skimmed milk
  • 200g baked beans with 2 wholemeal slices of toast
  • 60g raisins plus 50g nuts


You can’t run a marathon on a low carb diet or an empty stomach.

With the right diet plus enough carbohydrates and protein you can recover well and perform at your best.

The calculations above are guidelines, remember it is not one size fits all! These are general recommendations. You must consider your gender, age, fitness level and dietary requirements amongst other factors that could increase or decrease your requirements.


So how much carbohydrates do you need and are you depriving or over indulging yourself without knowing?

Work out your guideline amounts and see how much your performance and recovery change (if at all, you may have it nailed already!).

Further Reading

Don’t forget about hydration too, as this is equally important.

Check out our training advice on how to reduce your risk of injury throughout your marathon or other endurance training and on the big day.

Make sure you have a recovery plan. We have some advice to help you recover more efficiently.

Performance and Recovery Enhancing Sportswear

Don't forget KYMIRA Sport has a range of sports performance and recovery wear to improve your training and recovery such as leggings, tops and socks.

All KYMIRA Sport products have infrared capabilities which have numerous biological benefits!

KYMIRA Sport endeavours to help you train harder for longer and recover quicker.

September 24, 2018 — Lisha Armstrong

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