Sam the fat burner


Sam Wallace before (November 2015 and after (Feb 2016) his low carb healthy fat change


Sam does the weather and then talks fat burning after his VO2 and metabolic flexibility testing at our AUT Millennium Human Potential Clinic

Last Friday Sam Wallace, Television NZ’s roving weather man visited our lab to do his weather cross.

We tested Sam lat least year and advised him on some serious dietary changes – cut out the carbs and eat more fat.  Train your body to become a fat burning machine. Or in science speak – “stress your brain and body with low carbs and learn to supply energy from ketones.  Get yourself metabolically flexible.

We felt he would have a better energy supply (he was bonking 90 mins into his rides), he would feel better (maintaining his high energy over the day with super early starts for breakfast TV was an issue), and he would lose some unwanted extra body fat (it pays to be lean for cycling long distances, and you look better – see above – he does look better!).

Well, here are the results.

  1. 4.5 kg weight loss
  2. Feeling full of energy, and any anxiety around harder TV segments disappeared
  3. Improvement in VO2 max of nearly 20% from 40 to 48.5 mlO2/kg/min. OK he actually trained more so that’s only partially diet related. He did around 1600 km cycling  over three months which isn’t loads but still adds up.
  4. His maximum power improved from 300 Watts to 370 Watts on the VO2 ramp test (again training helps).
  5. Sam went from being a carb burner to a fat burner. At 100 Watts and 140 HR in the first test he was burning exclusively carbs and no fat. In the second test he was burning exclusively fat right up until he hit around 220 W and then was able to maintain a 50/50 fat/carb burning mix until just under 300 Watts.

In other words….Sam became metabolically flexible. He trained his body, through diet and some exercise, to use more stored body fat as fuel and reply less on carbs. This means he creates less inflammation and reactive oxygen species when he exercises – meaning he spares his immune resources and recovers faster, feeling better. It means he spares precious muscle and liver glycogen (sugar) and can access his fat stores – this means he’ll burn fat and lose fat, as well as not run out of glycogen while cycling (he is more or less bonk proof). And last, because he burns exclusively fat when he is resting and walking around he won’t fall off the glucose cliff every few hours and be driven to find high carb food.

He’ll have sustained energy and be able to stay lean!

Good stuff Sam.

I’ve included a short excerpt from our latest book –  What the Fat? Sport performance below about the whole concept of metabolic flexibility if you are interested.

Metabolic flexibility – The ONE big idea to understand

Metabolic flexibility really is the holy grail of nutrition for sports performance. Understand this and you will give yourself a powerful new weapon in your competitive toolbox. After all, knowledge is power! You will see how it’s actually done in the chapters that follow, but in the meantime, it’s important to know the science. We know science can be heavy going for the non-science-wired mind, but we really want you to understand the fundamentals, so we’ll guide you through it slowly and keep the really technical stuff for the ‘Extras for experts’ section at the end of each chapter.

Humans are designed to be metabolically flexible. That is to say, if you want to get the best out of your brain and body then you should be able to rely on fuel from both carbohydrates and fat as and when you need them. Someone who is metabolically flexible can use fat as the primary (and almost exclusive) fuel when they are resting, sleeping and moving around at a fairly slow pace. As they start to move around at a quicker pace – like fast running – they will be able to take advantage of extra fuel supplied by carbohydrate, and when they are going nearly flat out they will rely almost exclusively on carbs for fuel.

We measure metabolic flexibility in our lab using online gas analysis. We measure proportions of inhaled and exhaled oxygen and carbon dioxide to understand just how much fat and how much carbohydrate someone is using from rest to flat out exercise. What you want to see is represented in Figure 1.1; that is, this athlete mostly uses fat for fuel at low running speeds and mostly carbs at faster speeds. This athlete is a male triathlete who has been eating Low-Carb, Healthy-fat for over two years. He is highly metabolically flexible.



Figure 1.1: Calories per hour derived from carbs (red) and fat (yellow) [vertical axis] for a metabolic efficiency test; treadmill-running speed (min/km) [horizontal axis] using respiratory exchange. The athlete is a 39-year-old male elite triathlete who has been LCHF for at least two years.

Other athletes we test aren’t as good at using fat as this athlete. Here’s another test where the athlete is metabolically inefficient (Figure 1.2). This woman is a pretty good age-group triathlete, but she is really not able to access her body fat stores as a fuel source at any exercise intensity.


Figure 1.2: A metabolically inflexible athlete. This is a high-carb eating, high-level age-group female triathlete.

These two athletes are chalk and cheese. One can easily access his body fat stores as primary fuel at low exercise intensity. He can provide energy from fat right up to very high exercise intensity. He is a fat-burning machine who can access the tens of thousands of calories of fat he has stored around his body. He can maintain a healthy lean body weight easily and doesn’t have to eat sugar and carbs every time he goes training.

The other has to rely on the very limited carbohydrate (around 2000–2500 kcal) she has stored in her muscles and liver. She has to eat extra sugar every time she trains and fuel up again afterwards. She’s tired and has trouble getting her weight down to race.

Being a fat burner has obvious advantages in some sports, like endurance where having enough fuel to make the distance is an issue. Endurance includes long distance running, triathlons, cycling and anything else where you are training, racing or competing for a few hours or more. The fat burner has access to a big fuel tank (fat) and can spare the small tank that provides extra power when you need it (carbs). You can go faster for longer.

But it doesn’t stop there. The fat burner has the potential for significant health and performance advantages in any sport where weight, cognitive performance, fuel, and high training and competition loads are a factor. This includes weight class sports, all day sports like sailing, and team sports.

What the Fat? Sport Performance.  Leaner, fitter, faster on low carb healthy fat

21 Comments on “Sam the fat burner

    • Most likely hair loss is temporary due to changes in testosterone levels and also in thyroid function. However, it can take a year or more to be fully back to the “before” state.

    • Dunno what you Aussies do thats your own business…ha ha. But I mean completely expending your muscle and liver glycogen – were you thinking of something different?

  1. HI Grant, I have a question, I have been following a LCHF diet for the past 6 mths, I have lost 3kg not intentionally but just as a result of the lack of carbs. I actually would like to put on some weight but don’t know how to do it on this way of eating as I just don’t get hungry, any suggestions? I am 5’6 and weigh 58kg and I am 58.

    • Half your luck as thats not the trouble most people have! Have you tried a carb day a week and how will that feel? Sometimes that can help. Also, up the carbs t another 20-30 g a day?

      • Yes I have upped the carbs by eating more fruit and added in potatoes, I am trying to stay off gluten, not because I react to it, just I don’t think it is a healthy food. Should I take more coconut oil? I sometimes put it in my coffee or the more fat I eat will I burn it more, I don’t exercise excessively just walking and a few press ups.

    • You could try Mauro DiPasquale’s “metabolic diet”. It requires transitioning to a fat burning metabolism by keeping carbs very low and then once adapted, choosing a day or maybe two to eat a “normal” high carb diet. It was originally formulated for bodybuilders and works on the theory of using food to manipulate the big 3 growth hormones, Testosterone, Growth hormone,and Insulin, all whilst keeping fat levels down.

  2. Hi Grant,

    Your research is geared more towards endurance type sports, but have you had success in applying high protein – high fat to predomantly anaerobic strength-power sports (olympic weightlifting, powerlifting, throwing, etc) where energy requirements do not rely on fat burning per se?

  3. Hi, I’m a 37 year old woman, I have coeliac disease hence I’m GF, I’ve also been sugar free and grain free for the past two years due to a disaccharide deficiency (Maltase and sucrose) diagnosed via scope. Initially I lost 12kg and felt great, eagerly was up etc but for the past 6-9 months the weight has been going on and I’ve nearly regained it all plus I’m feeling tired and grumpy all the time, basically a complete reversal and yet I haven’t changed my diet, why is this.

  4. Hi Grant! I have just finished reading your book “What the Fat? Sport Performance. Leaner, fitter, faster on low carb healthy fat” and I have some question:

    # What do you mean that you can get fet adapted both via ketosis and gradually carb deprivation (under 100g) ? Do you mean that only when you are in ketosis you are fet adapted? If not, how do you explain the state when you do not take enough carbs but you do not produce any ketones?

    I mean, is it possible to be fet burner without being in ketosis? If that is a case, do your brain steel work on 60-70% ketones or just glucose?

    I’m hoping that you understand mine question. I have been on LCHF more than a year, and in ketosis around sex months and my experience is that those are almost two completely different states of metabolism.

    • Good question – I think you need to have sufficient metabolic stress for your body to up the fat burning – that means les than 120 g carbs a day. I prefer to go straight into serious carb retraction (ketosis) to drive the best adaptations. It is possible to get similar results over a longer time with more gradual and less serious car restoration. You will reply less on ketones and more on carbs for brain fuel during this approach.

      But in this book I am primarily interested in fat burning during exercise – I think you can see good effects even if not in full ketosis (which most athletes won’t be beyond the first adaptation phase).

      So it’s first a matter for teaching your body to burn extra fat and you need carb restoration to do that. I prefer the more aggressive ketosis approach simply because it will happen faster and most athletes are in a hurry.

      But you don’t have to b win fun ketosis to maintain that adaptation.

      • Thank you for answering me.

        So, you are saying that even if you are not in ketosis (>0.5 mmol/l) but in “low carb mode” that your brain will use some ketones as fuel.

        I simply don´t understand difference between fat adapted state without being in ketosis and low intake of carbs without being fat adapted (the state when you brain is carb depleted but there isn´t ketones to fuel it).

        Do you mean that that first adaptation phase is necessary to kick of ketone produktion and that you can go upp in carbs later and still has the similar effects? But if you just go low carb (the same amount) without the adaptation phase you do not start any ketone produktion and your brain will suffer?

        I’m not big on praise but I wont you to know that your book is very update and maybe the best there is on subjekt exercising and being low carb. The only thing I need is just this distinction between those different metabolic states.

        Have a nice day,


      • My view is that there are a few different ways to improve your access to burning fat over a range of exercise intensities -either hard out ketosis for a period, then a more liberal use by still carb restricted diet OR a carb restricted diet which doesn’t get ketones > 0.5 m mol. I prefer the first strategy as I think it gets better results. I wouldn’t advise a serious endurance athlete to stay in ketosis the whole time as THERE ARE BENEFITS TO THE ANABOLIC EFFECTS OF CARBS OCCASIONALLY

  5. Hello ProfGrant,

    In Point 5 you mentioned:

    Sam went from being a carb burner to a fat burner. At 100 Watts and 140 HR in the first test
    he was burning exclusively carbs and no fat. In the second test he was burning exclusively fat
    right up until he hit around 220 W and then was able to maintain a 50/50 fat/carb burning mix
    until just under 300 Watts.

    Do you happen to know what was his PULSE at 100 watts on exclusively carbs (before) and exclusively fat (after his metabolic adaptation) ?

    thank you

      • two identical twins*: one went LCHF one went HCLF – the nutrition coach for team sky took them on a ride up a hill in surrey UK. Each was given the same amount of calories – the HCLF rider received a gel of carbohydrate and the LCHF received a pat of butter.

        They started at the same measured pace, a short while into the ride they compared their heart rates 154 for HCLF and 177 for LCHF — the LCHF brother said that he felt like he was stuck in one gear and just watched his brother disappear ahead of him. When the LCHF brother reached summit his heart rate was a whopping 200 !!

        It certainly seems that the LCHF diet is disadvantageous from the point of view of cardiac efficiency.


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