Minimalistic Fuelling

by Mark Wolff


As far back as I can remember its always been very rare to cycle or run with a group of athletes who don’t have some form of colored drink in their water bottles or some spare change for that awesome sugar stop at the petrol station at around the half way mark. It seems that dependency on some sort of fuelling has not become just a necessity, but also the norm and I battle to find an athlete that even has the confidence to exit home without his or her fuel stash for fear of hitting the dreaded wall.

Now before you think here comes another weirdo who advocates keeping it all natural and only train and race on water, which I admit I am ;-), I am also the director of an endurance supplement company which provides fuel :-).

So how is it that on one hand I market endurance supplements yet on the other I am giving you a hard time for using them? It’s quite simple, supplements have a time and a place when they are suitable but they are not something to be completely dependent on. In actual fact the less dependent you are on a supplement the better the effects when you do use it. 

So firstly lets talk simply about how your muscles get their fuel to function. Muscles need energy to contract and this is done utilizing a chemical called ATP (adenosine triphosphate) which is primarily produced by our mitochondria. Carbohydrates, Fats & Proteins all get converted to ATP under a variety of conditions. Carbohydrates are more easily converted when exercise is done at a high intensity while fat is converted at lower levels of intensity. Protein is not a nutrient that is generally used to power muscle activity. Simply its a poor form of fuel and primarily used more for tissue repair.
So lets keep the focus on carbohydrates and fat. 

Glycogen (natural carbohydrate stores) is the quickest accessible fuel in the body and a person who has topped up glycogen stores will be able to provide anything from 90-120 minutes of energy to their system while performing at a high rate of intensity. Fat is a longer access path, but a truly desirable one as a gram of fat has twice the power as a gram of carbohydrate. Have you ever seen fat fall off a grill into a fire, it bursts into flames, this is very similar to what happens in your body, it fires the muscles extremely well when harnessed, it’s an incredibly strong form of fuel and if you are efficient at using your fat stores it will see you a long way. 

Now the next question is how do you tap your fat stores? This is really dependent on the type of athlete you are, what you consume before and during exercise and the rate of intensity you are performing at.
Fat requires oxygen to be properly utilized (aerobic level of activity). If you can picture someone racing at a high intensity and he can barely breathe well then you are not tapping into your fat stores as you are not able to take in sufficient oxygen to be utilized for fat conversion. In this case glycogen will primarily be used. At this high rate of intensity an athlete will on average see 90 minutes of fuel, if he is really in a good condition up to 120 minutes of fuel. Lactic acid build up takes place at the same time that glycogen is primarily used and its really very difficult for the general athlete to sustain an incredibly high rate of intensity for such a long period of time. So what actually happens is a combination of glycogen and fat become your energy sources, as pace will land up varying.

This just demonstrates the importance of pacing yourself during an event in order to ensure you are able to spare as much glycogen as possible by using fat as the primary source of fuel if you are able to. The above is just a general idea of how the concept of fuelling works based on intensity.

Now lets throw fuel or supplements into the picture. If an athlete is performing at an extremely high intensity for longer than a 120 minute period you will want to try and spare the glycogen levels by consuming carbohydrates which are co-utilized for fuel as opposed to glycogen only. A percentage of glycogen is spared but not continual sparing, it will still deplete in time. The carbohydrate intake will just extend its rate of depletion, and the sugar to the brain will give that “feel good” feeling which assists performance perception. A carbohydrate dependent athlete actually has to have that brain feel otherwise he goes downhill :-). 

Fat on the other hand is an unlimited resource, you could easily do 50 marathons on your fat stores alone, even if you are lean its incredibly powerful. There are some issues with using fat though. The first is most people are carbohydrate lovers, and the brain will be magnetized towards sugar intake 🙂 and the second is that he rate at which fat is burned for fuel is too slow to support an extremely hard effort. 

The issue of wanting carbohydrates during exercise can obviously be resolved easily by consuming carbohydrates during exercise, however if you still want to harness your fat it would be in your best interests as an athlete to train your body to utilize fat as a fuel source at a higher rate of intensity which can be done. That way when your glycogen stores are depleted and fat becomes your sole fuel source you will not have to slow your rate of performance down too much in order to stay in a zone where you don’t bonk (hit the wall). 


What are the advantage to becoming a fat efficient athlete:

1. Definitely you will  notice a difference in body composition and lean muscle mass which will bode well for performance as you might be at a very optimum race weight which previously might have been too heavy.

2. Health – Preventing the excessive carbohydrate cravings and endurance athletes truly do fall into this trap of excessive sugar cravings post exercise. This causes pendulum swinging of blood glucose and insulin levels and you do put yourself at risk later on in life for weight issues, cholesterol or diabetes. Pendulum swinging leaves athletes especially endurance athletes eating inconsistently, I see it often. Lindt Chocolates become the order of the day. 

3. Performance – I can tell you this, you will start to perform far more consistently when you are fat efficient. The longer the event the far better you will manage. Your nutrition worries will be quite easily sorted and your focus will be mainly on effort. You will become an expert at managing your training and training nutrition where your energy levels will be far more balanced. When an athlete experiences sudden dips in energy levels its a terrible feeling and leaves you feeling fatigued and weak, however when you are fat efficient these peaks and troughs are so much closer together on the height scale that you don’t go through that personal hell most athletes tend to find themselves in at some point in a long endurance event.

4. The dreaded bonk – What bonk??? seriously if you are fat efficient chances of you hitting that wall are so slim. The transition from glycogen depletion to fat fueling is so transparent you wont feel it as much as an athlete who really has to have his glycogen because he is not fat efficient. 

5. Time – Yes you will have more time :-). Imagine waking up in the morning and having a cup of green tea then going out on a 3 hr run or a 5 hr ride and all u needed was water. No prepping your food intake or bottles etc and having to stress about things that much. 

6. Save Money – Yes, you will save a lot of money. OK, the fact that I own an endurance company means you will buy less of my product as you will use it more sparingly :-). However your health is far more important to me and I mean that sincerely. No need to live on a supplement, use it when you need it. You will also save money on food expense. If you are fat efficient you definitely wont eat as much as you do when you are pigging out on carbs and Lindt chocolates ;-). You eat less frequently so its a savings. I have run the numbers and even though carbs are cheaper, lets face it sugar is cheap you will save. You will also save on medical bills in the long run ;-).

So how do you become more efficient at utilizing fat for energy. Its actually quite simple, BUT I will say this you need to be consistent and disciplined. It also takes time, its not something that changes overnight but with time you will notice differences in your ability to fuel efficiently and you will start to find a zone of awesome balance, without the big roller coaster ups and downs experienced by most endurance athletes.

How do I become a fat fuel efficient athlete?:

1. Nutrition, Nutrition Nutrition 
I cannot stress nutrition enough. It does not help to have a very high carbohydrate diet, especially consuming carbohydrate foods which cause blood glucose spikes. You are doing yourself a complete disservice not just from a performance point of view but also from a health point of view. The way to naturally become fat efficient ie: burn off fat through proper nutrition is to reduce your carbohydrate intake, and when you do consume carbohydrates ensure the timing of consumption but especially the types of carbohydrates that you consume. Ensure they are stability carbs and not those that send you on roller coaster rides, so stick to low GI carbs its far better, only use higher GI carbs post hard workouts, unless you are racing.

I always tell people if you want to use and lose fat you need to learn how to eat fat. Its amazing how many people avoid fat, however fat is good for you don’t be persuaded into thinking the opposite. Paleo is a very big diet path these days and I don’t object to anyone going the low carb high fat route, I actually do myself however with slight modification.

An endurance athlete putting in around 20 hours or more of training a week will find that time for glycogen replenishment on a low carb high fat diet might be a little longer than usual and this is because of frequency of training which will ultimately lead to fatigue and decreased levels of performance. So I generally recommend two types of modifications and either one is actually OK.
My preference is to increase carbohydrate intake dependent on training days, time and intensity based. As an example on a single training session day my carbohydrate intake could be around 75-100 grams of carb intake, but on a double session day it could go as high as 175-200 grams. With experimentation over the past 12 years I have found this to work best for me, however some of my clients require as much as 300-400 grams and some can get away with less. Each person is unique and my advice would be to deplete carbohydrates slowly and then find that point where you feel performance and balance is achieved. The type of carbohydrates consumed and the timing of those types of carbohydrates are also significant.

The second method is what is called periodization so this could be following a low carb high fat diet for 6-8 days, followed by a carbo-loading period of around 3 days. This still allows the body to be fat adapted so that even during exercise your body will be trained to utilize fat very efficiently. The problem with periodization is of course timing, if you get it wrong especially before a race you might land up in trouble and flat. The second thing is that when you are consistent on a diet and you suddenly make a change expect some digestive issues and some discomfort. Some athletes still like it, I tend to avoid it. I rather focus on fat efficient eating based on the kind of training day and I find this to work best.


2. Training 
If you want to burn fat during exercise then you need to train accordingly and this means watch your fuel intake before and during training. The only reason to take on supplements during a training session is to for three things.

1. Very long hard session and you need to keep your glycogen stores topped up as you have another session shortly after.
2. The intensity and duration of the session is very high and without a supplement you will not achieve your session goal.
3. Training your gut (You cannot race on a supplement you have not tried, tested and gotten used to and I always recommend setting aside one or two sessions a week to mimic race nutrition to ensure you have it down packed). 
My advice is quite simple, and this is what I follow which works for me, but time periods will vary for many people depending on how efficient they are and how good their nutrition and fitness levels are. 

  • Up to 2 hrs of even a very hard session there is no need for fuel water is sufficient. However you HAVE to ensure a quick intake of carbohydrates and protein immediately afterwards in order to start the recovery process right away. Secondly you need to then consume a proper recovery meal which I suggest is balanced, complex carbs, protein and fat. A hard 2 hr session will deplete glycogen so you want to recover for the next. If your next session is only a few hours later than you might want to pre-fuel or fuel during this kind of session.
  • Long Slow Sessions -Whether cycle, run or swim, if this session is at a fat burning intensity then DONT fuel it with anything except water, if you are able to. Confidence will come with time, BUT the worst thing you can do on a session like this is take in gels or other spiking carbohydrate products because you are completely mitigating your ability to burn fat and you are most likely just gaining weight as opposed to losing.
    Make these session productive. I have done many rides of 5 hours or more on water alone, even 36-40 km runs BUT I have been doing this for years and my body has become very adapted over time to using fuel as fat at these intensities. People often ask me whats low intensity and that really needs to be perceived effort, or within a comfortable HR zone. As an example, my run pace over 36km’s on water can be 4:40 pace BUT for someone else it might be way to hard and they would need something slower. Some of the elite athletes I deal with can run on fat at 4 minute or just sub 4 minute pace which is incredible, BUT that is a very comfortable pace for them and they are in a fat burn zone.
    Last week I did a 5 hour water ride at 31 km’s/hr average, but just to demonstrate that I did not weaken as I often get told but you battle to finish without proper fuel its not actually true. On the way out on this out an back ride, I was averaging only 27-28 km/h on the way back I had to ride significantly harder to average out that pace but was fine. I was still within my limits. 15 years ago if I tried something like this even for a 2.5 hr ride I probably would have hit the wall so bad someone would have had to come and fetch me ;-).
    So I understand there is a start to this, it is a process but in time you will definitely become a fat efficient athlete.
  • Now lets say its just NOT possible for you to go on water, you are not adapted and not confident. It’s quite simple. Fuel yourself on your session BUT with a difference, fuel with non-glucose spiking products. Something that’s low to medium GI something that keeps your insulin levels low enough to ensure you are still burning fat yet making your brain happy and there are products that allow you to do this. 32Gi Endure I have to mention is exactly designed for that. It releases glucose at a slow enough rate making your brain happy and allowing you to still tap your fat stores. The other thing you can do is only take on water for 2 hrs and then introduce your nutrition so that your body has moved into a fat burning zone before you start consuming and this is done by many elite athletes, until they can increase the time on water.
  • Lastly I don’t suggest water training like this every single week and every single session. Start with a one or two and slowly build up, remember you need to recover you need to also understand what your next workout is and you need to fuel yourself accordingly.

In conclusion I just want to emphasize that at first glance maybe you think this is crazy or not for you, but I can tell you from personal experience and from the many people I deal with on a daily basis, this is certainly the direction to take, not just from a performance but from a health point of view. Remember baby steps get you there it does not happen overnight.
Get stuck into this journey and you will never look back.

Good luck

m 🙂


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Bronwyn September 9, 2013 - 11:36 am

You are a true inspiration Mark. Your insight and knowledge sharing means I trust your products more. Thanks for giving broader perspectives!

Brendon September 9, 2013 - 2:09 pm

Excellent advice and very well explained. I have been a LCHF runner for nearly a year and the benefits are exactly as you explained.

Daniel Rowland September 10, 2013 - 12:27 am

A great post. Thank you for all the detail and ideas behind becoming fat adapted. I will definitely be trying out your suggestions in my training and looking closely at my nutrition.

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orelando September 17, 2013 - 1:49 pm

Very interesting. Thanks for putting this all into perspective!

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