Marathon week nutrition do’s and don’ts

by | Apr 5, 2021

4 min. read

Before you go on to read race week do’s and don’ts, the most important lesson here is that the gut is highly trainable. Therefore, in the weeks and months leading up to race day when we are training our body and muscles to handle to 42.195km distance, we also want to train our gut to tolerate digesting fuel under the stress of running.

By far the number factor with athletes that experience gut issues on race day is that they haven’t trained their gut enough in training with fuel. Or even worse they go from no fuel in training to then trying to have too much fuel under the stress of racing.

PRACTICE really does make perfect as the gut is a working muscle too.

The week of race day

  • Don’t change your diet dramatically in the week leading up to race day.
  • Even in winter, Stay well hydrated, keep the colour of your wee clear to monitor hydration status.
  • Try to get more sleep throughout the week rather than relying on the night before (and then stressing about it)

Carbo loading

  • Race week is not a time to diet and deplete glycogen stores.
  • Carbo-loading isn’t fat loading.
    • 1-2 days before the marathon, the majority of your meals should be derived from carbohydrates. Think bread/rice/pasta/cereal/starchy veg etc with a small amount of protein/veg.
    • Don’t overdo the fibre, you have permission to have white bread, cereals, pasta etc. this will decrease the residual load in your gut and the chance of stomach upset on race day.
    • Sugary drinks/foods are ok in the carboload as they don’t have a residual load on the gut.
    • Have a dinner plan the night before, stick to your normal pre-race ritual/routine, stick up for yourself and don’t go out for dinner or eat a meal that you haven’t tried pre-race/run beforehand.

Race morning

  • Eat a light breakfast 2-3 hours before the guns goes off.
    • KEEP IT SIMPLE, rich in low fibre carbohydrates eg toast, crumpets, rice etc.
    • Limit protein/fat as this is harder to digest.
    • But only what you have trialled in training
  • OPEN YOUR BOWELS as often as you can pre-race.
  • If coffee/tea is part of your routine, GREAT, caffeine liberates your fat stores for fuel, decreases the perception of pain and improves performance.

Your race plan

  • Have a race nutrition plan that you have trialed in training eg gels, solids, electrolytes and water.
  • Know where the aid stations are and possibly use these as times to consume your nutrition eg a gel just before hitting a water station so that you can wash it down.
  • VERY BROADLY SPEAKING, aim to consume 50-90g of carbohydrate/hour eg a gel every 30mins or so.
  • Relax and bring the heart rate down as much as possible pre-ingestion as this will aid digestion.


Post Race

  • Post-race, have something ASAP.
  • Chocolate milk, milk of choice with milo/sustagen or a CHO/Protein based supplement is easy to digest and also rehydrates.
  • Respect the distance, keep grazing on fuel throughout the rest of the day to refuel glycogen stores and repair muscle fibres.
David Bryant

David Bryant

Dietitian and Team Brooks Athlete

  • Advanced Sports Dietitian
  • 2:48 Marathoner
  • 9:19 Ironman
  • On track for Tokyo 2021 in Paratriathlon (club footed)

Bottom line, the ideal time of day to exercise is when it is best for you. Although more research is needed in this area to draw a conclusion on exactly what time of day is the best to exercise, what we do know is that long-term exercise does in fact improve aerobic capacity, cardiac function, management of BMI, and strength. So, the evidence points to moving your body for overall wellness regardless of what time you do it.

Keep that spring in your step this season and embrace your Run Happy journey with Brooks Running!

Our writer’s advice is intended for informational or general educational purposes only. We always encourage you to speak with your physician or healthcare provider before making any adjustments to your running, nutrition or fitness routines.

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