by Mark Wolff

Today was a typical Thursday morning session usually an early morning ride with some of my fellow athletes out in the countryside. It is that time of the year where getting outdoors is pure soul food especially when its out of the city and in the farmlands.
My wake up call at the moment is around 4:30am until we hit later summer when we can leave earlier.  I grab a serving of my favorite TrueStart Coffee or a green tea, get dressed and head out the door. Training will start around 5:30am and then usually last anywhere from 2.5-3hrs. Today was a little longer due to some strong head winds over the last 30km’s and we only finished around 8:30am.

My fuel on the bike = NONE. Just a zero calorie 32Gi Hydrate electrolyte tablet in a single bottle of water. Post ride its a shower, get changed and then off to eat a recovery meal. Today’s was at around 9am and that was my first meal of the day. Scrambled eggs, salmon and avocado.
It was 14hrs since I last ate, with a 3hr training session in-between and a challenging bike course with lots of climbing and wind.

The reason for giving you insight into my morning routine is to throw some light on fasted training which I do constantly. In actual fact a week ago I went out on a 100km ride and about 5km’s into my ride I realized I had left my water bottle at home. I just kept riding, the temperature was cool enough where I realized my sweat rate would be lower and I could get through it no problem and I did. Just rehydrate when I finish.

Its quite a debatable subject and for many a mental challenge which is difficult to even comprehend.
I decided to take a look at my average HR (Heart Rate), Speed and Distance over the past few weeks of my fasted training sessions to give you some more insight into exactly what is going on, on  a physiological level.

On my longer training cycling sessions around 2.5-4hrs my ave HR is around 120-129BPM, Speed Ave:28-32km/h Climbing: 700-1000m Max HR around 174BPM of course in a hotter climate like I was in a few weeks ago average HR could go to around 136BPM.
On my shorter 40-80min sessions which are more quality sessions (Intervals, Pace etc) ave HR between 135-147BPM Max HR 181BPM

The purpose of the above data is to really demonstrate the reason why a fasted training session is completely doable. If you take a look at the average HR over a period of time especially on my longer sessions you will notice that I completely control my effort. I don’t go into a glycogen depletion state and I mainly access my fat fuel tank meaning I burn off a load of fat for fuel. This is especially true on the longer sessions where my average HR sits mainly in Z1-Z3 maximum and even then for short periods of time. While my shorter quality sessions do of course use a higher rate of glycogen as a fuel source but taking into account the time of intensity it will by no means deplete it.
Understanding the human fuel tanks to support your training effort is critical to understanding the fuel sources you will be using during your training session and if you understand what your body is capable of then you will have complete confidence in using natural energy stores to support you sessions. I recorded a video with animation recently explaining the human fuel tanks and how they operate during exercise, you can CLICK HERE if you want to watch to get an idea of how they work.

So how is it that someone like me can ride or run 3-4hrs without any fuel but then someone else comes along and just hits the wall and completely fades even if the person is plunging a load of carbohydrates into their body to prevent it. Its quite simple. There are 3 factors that need to be taken into account here and I will explain further.

  1. Fat adaption takes time – Your body needs to learn how to change and become fat adapted. Think about this your body is used to maybe a pre-training meal and fuel during a training session. Your mitochondria which are there to create ATP (to fire up those muscles) are like your little community that you feed and they move around in concentrations dependent on where they are needed the most. Its like someone moving cities for employment ;-). When a muscle is worked over and over it will over time build up a stronger community or force of mitochondria which are used to create energy for that muscle. Stop hiring ie: the muscle doesn’t work and the community will shrink and look for work elsewhere. Just as exercise especially intense exercise can increase concentrations of mitochondria. We need to look at the fuelling process as well. The mitochondria in the muscles become more efficient at burning fat stored within the muscles (intramuscular triglycerides). This makes the body about 25% more efficient at burning fat. Most fat is stored in the form of adipose tissue and should be mobilized  and transported into the muscle cells for energy conversion. When a person constantly uses carbohydrates which cause a rise rise in blood glucose the ability to allow the body to use more fat for fuel is lowered significantly. Eating carbs before and during exercise will not make you a fat burning machine by any means. In actual fact when I train with athletes who load themselves constantly with carbs but don’t run the engine to the extent they require them I mostly see roller coaster rides and complete energy fatigue.
  2. Pacing is key – Make sure you don’t over cook yourself. Train within yourself and by this I will use the following analogy. You have a box of matches with around 15 matches in lets say. Those are your glycogen rockets. Each time you push your pace very hard you burn a match or two. If you use up all 15 matches before the end of the your session you are going to hit the wall. Keep your ego in your pocket exercise within the correct zone and you will spare your fuel that much longer.
  3. Loading with Carbohydrates mitigates a higher rate of fat burn and over time glycogen depletion takes quicker than a more fat efficient athlete. Glycogen might be required for some efforts but if you can use more fat to spare glycogen as opposed to sugar well you are in a far better space you will spare it for longer and have more rocket fuel when needed.

It sounds quite simple in theory but in practice it will take time. I usually suggest getting used to fasted training by doing it on shorter sessions and only over a long period of time attempt longer sessions. Remember you are educating your body, training it and the usual energy pathways you were used to in the past are not going to be the same going forwards and this process does take some time transition.  In endurance sport being a fat adapted athlete means a far more efficient and powerful energy system over time. Burning more fat at higher intensities than the average Joe or sugar freaks is a major advantage especially in long endurance events. If you are a sugar burning athlete your stores will deplete far quicker than mine.

I will definitely touch more on this subject over time as I am sure many questions will come from it. However from a health perspective remember our bodies are made to burn fat in a normal metabolic state and this is why weight gain and disease is so prevalent in our world today. Sugar is over consumed and never justified. So my answer to the question to eat or not to eat is eat correctly and when its needed, but to ruin a great training session? No chance, absolutely burn that fat.

All the best


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nikitafensham September 28, 2017 - 7:39 pm

Practically how do we become more fat adapted while avoiding the risks associated with low carb, especially hormonal?

Mark Wolff September 28, 2017 - 7:49 pm

Actually lower or carbohydrate periodization is superior to any other form of eating for the endocrine system. So for hormonal issues or changes the higher carb diets will cause way more havoc. Who said that low carb diets will impact it negatively 🙂

Mark Wolff September 29, 2017 - 6:38 am

Something I forgot to mention is I’m not talking Banting 🙂 carbs will be consumed but the correct amount and timing perfect to ensure they used and fat burn state is maintained.

Stefano Migliore March 26, 2018 - 6:49 am

HI Mark I attended your talk at Bedfordview Athletics on Saturday but unfortunately had to leave at 19h30 so I missed the opportunity to get to the end and ask some questions. The question I am really in need of an answer is this – I have been quite diligent with intermittent fasting training and a low carb diet – I eat my last meal by 20h00 and by 5am I’m out running and cycling – anything up to 25km of running I do in a fasting state with water only – I finish by 7 am or so and then continue fasting until 12h00 – I am not sure if this is right in terms of recovery or whether I should feed (and break the fasting state) after the workout?

Mark Wolff March 26, 2018 - 7:26 am

Hi Stefan do you have an email address ? Will reply there

Stefano Migliore March 26, 2018 - 7:37 am

Stefano Migliore March 26, 2018 - 10:05 am

Sent from my iPhone


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