Experts are great. They can tell you all manner of things about their area of specialism. They are especially good at telling you about stuff you’ve never even heard of. For example, did you know that “the magnetic moment of a free atom has three principal sources: the spin with which electrons are endowed; their orbital angular momentum about the nucleus; and the change in the orbital moment induced by an applied magnetic field”?
I certainly didn’t. Fortunately, it was an expert in the field (no pun intended) who wrote this to enlighten all who come across it.
All well and good, but what happens when so-called experts start telling us things about which we know a great deal? What happens when people with many more qualifications and years of research experience start telling us things that we know don’t work like they say?
Let me explain.
I am a runner. I’ve been running for over 20 years now. For most of that time I’ve had a thing about running a long way. A 40 mile race in 1998 (a few weeks before my first attempt at a marathon) convinced me that longer is better and I’m now a veteran of more ultramarathons than I can actually put a figure on. I can therefore state, with a reasonably high degree of confidence, that I am an expert in the field of how my body reacts when I run a long way. I’ve run tens of thousands of miles over the last twenty something years, at all kinds of different intensities, over all types of different terrains, in all sorts of weather, at every time of year, wearing running clothing for every season and a range of different running shoes that would make Imelda Marcos blush at the sheer number.
I’ve also tried different nutritional strategies.
Which leads me on to my point about the experts. According to the experts, endurance athletes are optimally fuelled taking on board between 30-90g of carbohydrate per hour. This allows the “fuel tank” of muscle glycogen to remain topped up and gives the muscles the maximum supply of easy to get to energy. There are all manner of race foods and supplements out there that enable this steady supply of carbohydrates, ranging from sports gels, through powders to mix with water, to the good, ol’ fashioned jelly babies and flapjacks.
Using my own personal triumvirate of experience, common sense and rudimentary knowledge of physiology, I have some issues with this expert advice.
My last race (214km) took me 37.5 hours. That would mean trying to consume 1.2 – 3.7kgs of carbohydrate. And that doesn’t include protein intake, which would increase the amount of sustenance I’d need to consume to levels that frankly would require me to push a shopping trolley round with me. Given that the race was off road, you can imagine the problems that would throw up.
Speaking of throwing up, by applying some very basic physiological principles, it is very easy to spot another flaw in this expert plan. When someone runs they are, by and large, relying on their sympathetic nervous system to direct an increased amount of blood to the muscles, which are working pretty hard for the bulk of the race. As a result of this the parasympathetic nervous system takes a bit of a back seat and pretty much comes along for the ride. The parasympathetic nervous system however, is very important for digestion; diverting blood away from the muscles and towards the gastrointestinal tract (in normal circumstances mammals tend to rest up a bit after eating to allow this to happen – not really an option when racing). This simple inability to balance the two branches of the autonomic nervous system is the major contributor to endurance athletes suffering from all manner of stomach troubles, be it undigested food going straight through without passing go or collecting £200, bouncing back up from whence it came or, my over-eating nemesis: bloating problems causing violent hiccups. I have no statistics to back this up but I am convinced that more people drop out of endurance events because of stomach troubles than any other reason.
So, what is the alternative to the so-called “expert advice”?
In 2014 I entered a race called T184. This was a run that went from the Thames Flood Barrier, all the way along the 184 mile Thames Path to the source of the great river, near Cirencester. The T184 is not only a very long way to run, it is self-supported. This means that runners are not allowed support crews, cannot buy sustenance at shops along the way and are only allowed to take on water from one of the 7 checkpoints or taps and stand-pipes along the way. All food had to be carried or foraged from the hedgerow (as it was held on August Bank Holiday weekend the blackberries were in plentiful supply). My nutrition preparation for this race had to be a bit different to normal and I started to look in to foods that were high in calories, low in weight. Below, is a table that anyone who has even a passing interest in nutrition will be very familiar with:
It probably doesn’t need me to tell you which macronutrient featured heavily in my backpack for the T184. Fat. Possibly the most vilified foodstuff known to man. If I could just get to Cirencester before collapsing from cardiac arrest due to arteries that would be clogging up at a rate similar to my overnight shuffle through Oxford…
Along with nuts and my specially concocted ‘Fatjacks’ (recipe available on written request) were pork scratchings. And it was these beautiful little porcine nuggets of crunch and energy that really got me thinking. Physiologically pigs are very similar to humans. Pork fat is how a pig stores energy that it doesn’t need to use immediately but is nice to have as a readily available source should the need arise.
If a pig creates this substance as a perfectly natural and super-efficient energy store and can break it down easily to use the energy on demand, why can’t I use the same substance in the same way? And as an added bonus, pork scratchings are lathered in electrolytes (salt) and taste amazing. Talk about a win-win situation.
I ran the race, finishing just under 59 hours and had the grand total of no energy crashes. I was tired, blistered, grubby, sore and generally unkempt when I crossed the line but I never once felt a lack of energy. It fuelled a desire to look into this further.
A 2014 paper by Jeff Volek1 provides a table that states someone of my lean frame (I’m 6’0” and about 11 ½st) has somewhere in the region of 2,000kcal available in the form of stored carbohydrate (muscle glycogen) and 30-60,000kcal available in stored fat. The human body will use the easy to get to muscle glycogen first and 2,000kcal will last around 2-2.5hrs (hence hitting the wall at this stage in the marathon).
The “fat-adapted” athlete is a concept that has been around for a while. There is a lot of discussion about whether it is the optimum way to fuel elite athletes – some of it civilised – but it is generally recognised as being possible. It basically means that the athlete will draw on the larger reserves of energy, stored as fat, to fuel the performance, thus avoiding the dreaded energy crash and dip in performance that is associated with it.
I have spent the last 3 years training when fasted and eating a lower carbohydrate diet to become fat-adapted. I can categorically state, with no ifs, buts or maybes, that this is by far the best way for me to fuel myself. And let me make this perfectly clear: I have tried fuelling using the high carbohydrate model, many times. I’m going to stick to the LCHF option and keep doing it regardless of what the latest research says. Because here’s the thing. Research is fundamentally flawed insofar as it is always done on other people. In the case of sports nutrition research is almost always conducted on elite athletes, which I am not and sadly never will be.
As far as I am aware there has only ever been one study on an ultra-runner who competed in a 184 mile race at the age of 42, who had been running for 20 years, who recently completed a 214km trail race (and won it, I may add!), who lives and trains on the Isle of Man, who runs with a Border Collie, etc., etc. That study is still in progress. It has had some interesting and surprising results. It is unlikely to ever be published in a peer-reviewed journal as the experts are generally not too interested in n=1 studies.
As for me, I’ll continue to monitor the results of the study very closely and will continue to adjust my ways accordingly. I rather like this n=1 study.
Rethinking fat as a fuel for endurance exercise. Jeff S. Volek, Timothy Noakes, & Stephen D. Phinney. Eur J Sports Sci, 2015; 15(1):13-20