How to nutritionally train for a marathon: Written by Rebecca Evans

Step 1:  Decide you are actually running a marathon (this step may occur 3 months out or even 6 weeks out after you’ve done the initial part of the training and had the moment of it hasn’t killed me yet…let’s do this!)

Step 2:  Start training….this isn’t referring to the part where you put your shoes on, go outside and run, this is more about your nutrition training.  One very big piece of advice I give to my athletes and I also use myself is: NEVER try ANYTING new on the day of a race/competition/event!  If you haven’t trained with it (meaning type, amount and timing) then don’t use it.  I have seen/heard many horror stories of people trying new gels, new electrolyte drinks and getting stitches/diarrhoea and stomach pains that have forced them to slow down and some not even finish.

A marathon is a 42km race and having gastrointestinal (GI) issues is something that you really want to try to avoid!  This is where the importance of nutrition training comes in.  Some keys things to note when training with nutrition:

  1. What is your pace/total time running (both for training and event runs)
  2. What is your preferred method of nutrition (i.e. gels, drinks, bars, lollies etc)
  3. How are you going to carry your nutrition
  4. On your route do you have access of water/fluid
  5. Pre-training nutrition and hydration strategies


Pace/Total Time

Why is this important to your nutrition needs?  Your body only holds enough glycogen (stored glucose) to keep the body running for ~90minutes  (this doesn’t take into consideration utilisation of your fat stores which come into play a lot when running at a lower intensity), therefore if your aiming to run the distance in 1.5hrs+ then you absolutely NEED some quick release carbohydrates coming into the body to keep you fuelled.  Generally speaking 30-60g per hour of fast digesting carbohydrates is optimal and nutrition should be started within the first 30mins of the race to ensure you don’t tap into the glycogen held in your liver until absolutely necessary.   Working out how much nutrition you need for your total run time is very important, which is where a Sports Dietitian can help plan your race nutrition plan.

Preferred method of nutrition

This varies from individual to individual and just because one method works for someone doesn’t  mean it will work for you.  Since running has quite the impact on the body it is common that GI distress occurs when eating/drinking too much at one time and therefore makes refuelling quite difficult.  One method that I use and have been using for my marathon training are gels.  Now it’s important to note that not all gels are created equal (taste/carbohydrate load/ease of use/fluid requirements when taking them/added ingredients such as caffeine).  Generally gels have roughly ~25-30g of carbs; Gatorade/Staminde/Extend/Endura drinks have ~30g carbs in 500ml.  For convenience and to decrease possible GI distress I do recommend gels more than liquids BUT liquids serve a very important role in your hydration status so working between the two can help meet your carbohydrate needs.  NOTE:  try different gels in training to get the best one for you…it took me a few runs to find nice ones and now I LOVE the gels I use and look forward to having them!

Carrying nutrition

This is a new concept to me in my training regime and I have finally bought a running belt (as seen above) and it works great!  My nutrition strategy for the race is one gel every 30 mins, therefore to meet my target of under 4hours I need 7 gels on the run and I would normally have 1 caffeine gel 10-20mins before the run.  There are many types of belts to choose from just make sure you train wearing it on your long runs, especially if you have a bottle holder (2 or 4) belt to know the weight you will be initially running with, where it sits best to minimise movement and also if you get any chaffing from it.


Water/Fluid access

This is a really important issue that does get overlooked when trialling nutrition, most gels NEED to be consumed with water for them to work effectively.  Too much carbohydrate in one hit without the appropriate amount of fluid can slow down gastric emptying and reduce the availability of the carbohydrates and could also lead to GI distress.  Many gels have instructions either on the package or on their website so make sure you research what your particular gels require.   As a guide I recommend a minimum of 150-200ml water every gel, check your course for water/fluid stations so you can time your nutrition to have access to fluids.


Pre-training nutrition and hydration strategies

If you start a race glycogen depleted or dehydrated you are going to struggle.  So how do you do you make sure you have enough glycogen on the day (training and race day)?  I start my race nutrition the day before by consuming a minimum of 7g/kg/carbohydrate which equates to ~440g carbohydrates for me (see below to see what this looks like).  To fit all of this into my daily life I aim to eat every 2-3 hours, making sure I have carbohydrates at every meal.  I recommend minimising high fibre, high fat and spicy foods before a big run and keeping foods simple.  My general rule of thumb is to keep things fairly similar the day before, especially when it’s the day before the race/event.  The morning of the run ,choose a breakfast that has a little bit of protein (helps to fill you up) but primarily focus on getting some carbohydrates in to your body to replenish your fasted state.  Again, keep this meal low in fibre and fat and make sure you have trained on this type of breakfast before.

Hydration is a very big concern when running a marathon, a 2-4% decrease in body weight can cause fatigue, decreased endurance, headaches, nausea, overheating and heat cramps….any of which will make an already physically challenging marathon that much harder!  A tip I use with athletes is to check that you’re hydrated prior to starting.  A quick and easy way to do this is to check your urine.  If your urine is fairly clear you are hydrated; if however, you’re dehydrated your urine will be quite a dark yellow.  Aim to go to bed in a hydrated state and first thing when you wake up drink a minimum ~200-300ml water.  During the race keep fluid intake at a steady pace; aim ~150-200ml every 20mins.


For those of you heading into the Gold Coast marathon you only have 3 weeks until the big event…. So book in with your Sports Dietitian to finalise your race plan, if you haven’t already started trialling or training with nutrition it’s not too late!  Start trailing even on smaller runs if you have started your taper already and remember never try anything new on race day!!  Happy running 🙂

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