Its that time of the year in the southern hemisphere where peak racing season has kicked off and in full swing. Last week in particular I spent my time at the expo of the 2nd largest timed cycle race in the world the Telkom 947 Cycle Challenge. It’s quite an experience engaging with athletes from all walks of life from the couch potato turned health nut, the weekend warriors to the real competitive race snakes.

I spent most of my time deep diving into the human body and how each athlete needs to fuel uniquely to their specific needs. Its amazing how many athletes had not given much thought to the nutrition surrounding the event and are just about to try to fortuitously perform. In endurance sport this rarely works and actually the opposite it makes for a miserable day out.  Proper sports nutrition is the foundation on which the athlete has the ability to maximize his or her energy system and perform at their greatest potential in the most comfortable manner. Get this right and you will want to be back quickly. Get this wrong and you will never want to return.

With this in mind I want to change that mindset that sports nutrition should be an after thought and that training is more important. Absolutely Not!
One cannot out train a bad diet as much as they think they can it doesn’t work and in the same token its not possible to gamble on your training and racing fuelling strategy. Just like anything in life practice makes perfect and understanding how the human body functions under stress well as understanding how your unique make up will fair over the distance needs to be taken into account.

In this particular blog I am going to focus on the fuelling side of sport and give you a general way to approach it logically. The way I generally engage with any athlete is to first understand the following:

  • What kind of an athlete are you?
  • What time will you be training or racing?
  • How long will you be training or racing for?
  • What intensity will you be training or racing at?
  • When will you be training or racing again?
  • Weather conditions you will be training or racing in?
  • Whats your preference liquid feed or food solids or both?

These questions are important to understanding exactly what the person is about and what he is going to be putting his body through as well as the conditions. If these points are not all taken into account you could be setting yourself up for failure.

Lets delve into the list above and break it down to be a little more clear.

What kind of athlete are you?
A high intensity performing athlete placing their body under extreme stress will certainly require a different feed from that athlete who is casually doing a social run or ride. You see its quite simple the athlete that goes at a very high intensity will be limited more as digestive system is more sensitive under this type of stress. Another thing to take into consideration is that the athlete will highly likely deplete his or her glycogen stores at a higher rate than the lower intensity athlete meaning a higher carbohydrate feed will need to be looked at in order to spare as much glycogen as possible during his or her effort. A more social athlete doing an event for fun or at a far more controlled pace will get more oxygen into the system over time due to more controlled breathing and in this case a different type of a feed can be considered as oxygen into the body over time ultimately determines which fuel tanks are predominantly used during exercise. (See my video explanation of the human fuel tank usage based on effort). In other words if you are an athlete doing a fun session or a lower or more controlled intensity event do not try to fuel like a pro or a race snake you are just going to cause havoc with your energy system. Fuel your effort.

What time will you be training or racing?
This is such an important factor. Ever noticed how so many athletes wake up at 4am to train or others at 17:00. The problem here is that a race doesn’t usually start this time. An athlete should always try to train at similar times to race times at least two times a week if possible. One needs to acclimatize to the race conditions and experience those temperatures that you will be racing in. The energy system also changes during the day and training your body at certain times which are nowhere near race times will ultimately cause discomfort when doing the actual race. A simple example is a friend of mine a runner, who trains every single morning but then he did an afternoon marathon but had never ever run at that time. It was an absolute disaster for him. Over and above the acclimatization, early mornings are cooler requiring less hydration but as the temperatures rise one needs to ensure that hydration is understood and done correctly. Last year I did a 204km trail running stage race in a team of four people. The race started at 13:30 in the heat of the day and continued until 19:30 the next morning. In order to understand my hydration and fuelling requirements and how my body would respond I occasionally trained  3 times a day morning, lunch time and evening. I needed to experience the various conditions and to allow my body to adapt to what it was going to face on the big show down. As a wise man once said, if you fail to prepare, prepare to fail.

How long will you be training or racing for and what intensity will you be training or racing at?
Proper fuelling requires a view of time versus intensity. I did mentioned intensity earlier on however the human body is limited as to how long it can perform at a high intensity. We basically have two major fuel tanks being glycogen and fat. Glycogen is our rocket fuel tank short lived and fat more our diesel engine fuel longer lasting. The table below shows approximate time that each fuel tank will last over a range of intensities.

Max Effort Glycogen 60-90 minutes
High Intensity Glycogen / Fat 90-120 minutes
Medium Intensity Fat / Glycogen 2-5 hrs
Low Intensity Fat 5 hrs Plus

*Well trained athletes can extend their ranges quite significantly

Based on the above you will need to understand that you cannot race extremely hard for an unlimited period of time as once the glycogen stores are depleted your body will slow down in order to accommodate more oxygen and of course allow for higher fat fuel usage. Meaning that the duration of exercise will ultimately determine the pace and you need to fuel that pace in order to ensure you have matches in your box for the final leg. I have seen too many athletes burning their matches early on only to succumb much later to complete fatigue. The longer the event the far more you need to pace yourself and the fuelling strategy you utilize needs to match that level of effort.

When will you be training or racing again?
Crucial question as not all races are one day events. When it comes to stage racing you have to consider how you will fuel yourself during the event to ensure that as you finish the stage you already start the recovery process. Once you complete the stage, recovery must begin immediately to make sure you are strong for the next stage. Many athletes fail to prepare themselves properly for this aspect of the race and as each stage goes on they become weaker and more fatigued eventually succumb to the pain the body is feeling from the lack of recovery.

Weather conditions you will be training or racing in?
Earlier we mentioned climate but you need to take into account the actual weather on the day. It might be a hot time of the year but the day of the race could come with strong winds or rain, or much hotter temperatures. In either of these three factors the fuelling strategy can vary slightly. I will give you an example. Rain means less sweat, means less hydration which means if you are relying on your liquid carbohydrate feed from the bottle and you land up drinking less due to less fluid required you will be calorie deficient and your energy system will crash. You need to keep hydration and energy completely separate and make sure no matter what the weather you have a fuelling strategy that is simple enough to cater for both. Strong winds can mean a longer day out, it can also mean more energy exerted to move over distance. Think about how it would affect your time and intensity and ensure your fuelling strategy caters for both.

Whats your preference liquid feed or food solids or both?
Food textures are so crucial when it comes to fuelling. An athlete that has never used liquid fuelling and then suddenly attempts it on the day is just asking for trouble. You need to train your gut during training to adapt to a certain type of fuelling and attempting it on race day is not very wise. My take on liquid versus solid is quite simple in that if you are performing at a very high intensity its not possible to be chewing much on a food solid as you need to keep your airways open in order to breathe. However if you do have the ability to take on food solids its not a bad idea as the human body is certainly used to consuming food solids daily. Just ensure its not going to impact you negatively and that the digestive system will handle it under stress.


I have given you a lot to think about but I have not really explained how to approach it in a very simple manner. My rule of thumb is take in the least amount of fuel to achieve the greatest desired result. Do not over do fuelling get it right. My general recommendation is to fuel short high intensity efforts with a quicker releasing carb feed and the lower or more controlled paced longer efforts with a stability carb feed. The next rule is never to leave wide time gaps in your fuelling strategy. Smaller frequent feeds are way easier on the digestive system but far better for the energy system in that the stability drip feeding provides will stabilize you far better by reducing the peaks and troughs of your energy pendulum. Clock feeding is definitely advantageous in endurance events. Knowing when and how much to consume will see you being able to perform at your best. Keep it simple, don’t over complicate the fuelling and finally don’t take chances. Prepare your fuelling strategy way in advance and test it over and over again until satisfied. Once confident its the way to go then bank it and stick to it on the big day.

All the best




Mark Wolff is an endurance, nutrition and physiology expert with over 20 years experience. An endurance multisport athlete with a 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 down packed. 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 a certified sports nutrition expert as well as a marathon, track, triathlon and cycling coach. He spends most of his time guiding athletes with a very holistic approach to blending training and nutrition for performance and health

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