by Mark Wolff

With only a few weeks left to Comrades Marathon there is a lot of chatter going around on fuelling, hydration, cramp prevention and immune system boosting to ensure health and decent day out. Unfortunately most of the advice is personal opinion without a clear understanding of what the human body actually requires in an endurance event over a long period of time.
As far as immune system strength goes I will touch on that in a separate blog to dispel the crazy myths that so many think work. In this blog I will cut through the nonsense and explain exactly how to approach your hydration and fuelling strategy for the big day.

In any ultra distance event there are three main areas of focus that need to be adhered to.

  1. Pre-Race Meal
  2. Fuelling Strategy
  3. Hydration Strategy

If you can nail these three you are sure to have a pretty decent day out. Unfortunately many athletes tend to forget about the importance of this and often leave it too late to try it out in training. A proper nutrition strategy needs to be practised many times way in advance of the event and under similar conditions in order to ensure that it works well. If you do not test your strategy and plan it properly there is an excellent chance that your day will go pear shaped.

The Pre-Race Meal
Definitely the most important meal of your race day. A pre-race meal is so crucial in terms of setting the body up for those first few hours exercise. It is the only opportunity to ensure your fuel tanks stay topped up in the hours leading up to the race especially after a night of fasting. Stabilising your blood sugar and ensuring some fuel for the first bit of your race.

The morning meal of race day is vital. The food you consume prior to your race will form an important part of your actual race fuel.
It’s best to consume a meal which will provide you with stability and give you the energy requirements you need during the event. This meal should be a sustainable meal including carbs, make sure it does not spike your blood glucose levels but provides balance. If you are caffeine intolerant you will be able to benefit from taking in caffeine at this point.
Your meal should be consumed at least 2 hours before the event and have a volume of around +-300 – 400 Calories. A meal should consist of easily digestible carbohydrates and some protein. Fibre should be limited as much as possible as it can lead bowel irritation and digestive discomfort. If you are even slightly lactose intolerant then avoid any dairy at all costs.
Some examples of a pre-race meal are listed below.

  • Rolled oats, peanut or almond butter, half banana
  • Toast (low fibre) oats or seed load, peanut or almond
    butter, honey, banana
  • Cereal or porridge (low fibre) with some fruit and nut butter.
  • Potato or white rice pudding
  • Pancakes
  • Eggs on toast

If you are a fan of racing or training on caffeine then now is the time to dose on it. Generally its recommended to consume around 1-2mg of caffeine per a kilogram of bodyweight. Caffeine has been shown to help free up free fatty acids which is an excellent source of fuel in a long distance event. It has also demonstrated the effects of delaying the onset of fatigue as well as improving oxygen uptake which of course is a major benefit to the energy system in any long distance event. Caffeine also plays a role in performance improvement during a long distance event. If you have no experimented with caffeine in training then do not try it on race day.

Some nutritionists advocate that you should consume heavy or blood glucose spiking products prior to your event to maximize liver glycogen levels. I am personally against this. The event is not a high intensity event its a pace controlled ultra and you will by no means be doing yourself any favours by elevating your blood sugar significantly. The opposite it will most likely cause some major issues early on. Lastly do not over hydrate prior to the event. This can cause an overloaded bladder and major discomfort. Moderate fluid consumption prior to the event is absolutely fine.


The best way to spare glycogen in a long endurance event is proper pacing, and moderate carb consumption. In an ultra marathon proper clock feeding or distance marker feeding (assuming you know your exact pace) is the ultimate way to fuel. We call this a drip feeding mechanism. The idea is to fuel smaller amounts more frequently.
Why is this a benefit?
It simply reduces the risk of GI (gastrointestinal distress) and prevents major peaks and troughs providing better blood sugar stabilization during exercise. Secondly it allows better fluid absorption as not a large amount of fluid is required with the intake meaning more manageable feeds to provide energy as well as fluid to keep you hydrated.
Consuming a high large amount of glucose concentrate (such as a standard gel) requires a fair amount of fluid to ensure a proper dilution ratio (isotonic) to ensure efficient fluid and energy pull through. Failure to do so will likely lead to gastrointestinal distress as well as dehydration.
Do not delay your fuelling in you race. Start early on and keep it consistent.
Mix it up nicely even combining some food solids along route such as bites of a banana or potato can make for a nice break in between the monotony of other feeds.

Its crucial to get protein in the system during a long distant event as well. I highly advocate consumption either hourly or at certain points in the event. It has been shown to help in delaying the onset of muscle fatigue as well keep you satiated topped up and the hunger at bay.

Below are examples of fuelling charts of elite  and amateur athletes to give you an idea of the planning that goes into place not just for training but from a nutrition perspective as well.

* The below charts are tried and tested method for an athlete of specific weight, pacing, fuelling and hydration requirements. Each person is unique in what they require and what works for one person will not necessarily work for the next.

The following products are utilized in the fuelling charts below

Elite Athlete Fuelling Structure

Amateur Athlete  1 Fuelling Structure

Amateur Athlete 2 Fuelling Structure

Elite Athlete 2 Fuelling Structure


Hydration is where most of the chaos occurs in an ultra distance event. This is very often when the wheels come falling off and the body just goes through a world of hurt and pain. I would even go so far as to say that proper hydration is even more crucial than energy intake.
You need to firstly understand that consuming water in large amounts on route does not mean you will remain hydrated. Hydration depends largely on the absorption rate of the fluid you are consuming. Water on its own has a low absorption rate as opposed to water consumed with a mineral solution (in particular sodium). When it comes to proper hydration the idea is to take in around 80% of fluid lost in the form of sweat. Small frequent sips of fluid intake will be easier to be absorbed however I would suggest consuming fluid with a mineral solution which is hypotonic or isotonic in nature to maximize the absorption of the fluid. I have written a previous blog on hydration which will help clarify this Simply Hydrate (Click Here)

Over consumption of water will only lead to what we call the washing machine effect. When the stomach gets overloaded with fluid as its not being absorbed and this can lead to a large amount of discomfort as well as in severe cases the dreaded hyponatremia. If you do feel fluid sloshing in your stomach and its not being absorbed you need to stop drinking immediately and consume something in the form of salt to help pull that fluid out. Once it empties you can carry on hydrating again. Under over hydrated circumstances very often thirst actually kicks in quite strongly so do not mistake this for dehydration it can be over hydration as well and your stomach will signal on which side of the fence you are sitting. One of the main reasons I developed the 32Gi Cramp Assalt gel (Click for more Info) was to address this exact issue. It’s a hydration gel which is designed to maximize fluid absorption during exercise as well as containing an anti-cramp trigger. Prevention however is better than cure and its an easily carried product which is sure to aid proper hydration.

In conclusion I just want to stress when it comes to fuelling and hydrating the least amount taken in to achieve the best result is what you should aim for. Under consuming can always be addressed but over consumption will swing the pendulum way to hard and leave you in a really tough space that will be pretty hard to get out of.

Over the next few weeks we will be giving a lot of tips and tricks as we head towards Comrades Marathon and hopefully we can guide you to your best day out.

all the best


Mark Wolff is a certified exercise & sports nutritionist, endurance nutrition and physiology expert with over 20 years experience. An endurance multi-sport athlete with a running, triathlon, mountain biking and weight lifting background, he works extensively with professional and amateur athletes in a variety of sports disciplines as well as those just wanting to change their lifestyles. He firmly believes that a person can only reach their full potential when their health and nutrition is given the proper focus. Mark’s focus on nutrition and physiology is not just on training and racing, but he places major emphasis on recovery, immune system health, emotional stability, stress management and performance. Mark is co-founder of 32Gi, a sports nutrition company, focused mainly on health and endurance nutrition. He is also co-founder of Rapid Recover focussed on pneumatic compression equipment to improve circulation for recovery and health. 

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