Following on from blogs one and two, I’ll now bring this mini series of blogs to a close with four final nuggets of wisdom that have helped to inform and improve my running performance. Given my role as a dietitian, I’ve decided to finish up with some ideas on nutrition. I’m not claiming to be an expert on sports nutrition (yet!), but I’m starting to move in that direction at least, so I hope you enjoy my thoughts below.
7. Running on ‘empty’ can be a good thing
When we train for a marathon, one of the key things we are hoping to ‘train’ our bodies to do is to use fat as a fuel source at higher exercise intensities, thereby preserving that crucial muscle glycogen until we really need it. Hitting the wall is all about running out of glycogen, so if you can burn more fat instead of carbohydrates, the wall will come later…or maybe even not at all.
Most resources suggest that we can store (if appropriately carb-loaded) around 2 hours’ worth of muscle glycogen for marathon intensity exercise. Clearly that is not going to be quite enough even for very quick marathon runners, which is why we need to a) refuel during the run and b) preserve glycogen through fat burning.
One of the theories, therefore, is that some of our training runs should be completed on an empty stomach, in order to mimic the glycogen-depleted conditions late on in a marathon, and to force the body to start using fat. This remains a contentious area though, and it is certainly not recommended to start doing this as standard (especially for very long runs), as there’s a good chance you won’t be getting the best out of your training. However, sometimes circumstances dictate that there isn’t enough time to eat before running anyway (forgot to set that weekend alarm, perhaps?), and on these occasions it could be a useful opportunity to vary things up with a fasted run, in a bid to improve your fat burning efficiency.
8. Embrace gels
In my early running days, I used to think of gels as unnecessary and a waste of money. As a dietitian, I am trained to support a ‘food first’ approach where possible (i.e. as opposed to synthetic alternatives), and I extended the same logic to running. Surely if you’ve carb-loaded well, that will see you through to the end? And if not, that’s where bananas, or at worst, jelly babies come in?
To answer the first question (carb loading) – yes, sort of, but as per my discussion on running on empty, you simply cannot store enough muscle glycogen for a whole marathon, so you will definitely run out of your primary fuel, hit the wall and slow down…significantly.
To answer the second question (bananas / jelly babies) – each to their own, really. Perhaps when I started running I was working at a slightly lower intensity than I am now, but I cannot imagine having to eat a piece of fruit during training, let alone a race. Jelly babies are probably still just about do-able, but really I’m now all about getting as much sugar in, with the minimum of fuss, as fast as my stomach can take it!
And for me, this means gels- isotonic, carb rich gels that are generally sickly sweet but seem to do the trick. On my longest training runs I sometimes take up to four (including some caffeine-containing ones for their potential performance enhancing impact later in endurance exercise), and might even be close to doubling this on the marathon itself. The only problem is how I actually carry these on race day…haven’t worked this out yet!
Having said all of this, I’m well aware that some people have real issues digesting gels (or anything, for that matter) during running, due to the blood having long since departed the gut in favour of the pumping muscles. I’m very grateful that this isn’t the case for me, but I would strongly urge any serious marathon runners to persevere and experiment with different gels in training, because if you find one that works for you, it genuinely can be a huge boost to performance.
9. Low FODMAP diet in running
Although my gut is generally quite resilient, I’m not completely immune to the disruptive impact of endurance exercise on my digestive system. I’m sure anyone who has ever run even medium distances needs no further explanation here.
In people with IBS, there is a huge wealth of evidence for what’s called the ‘low FODMAP’ diet. I won’t go into detail here, but FODMAPs are varieties of fermentable carbohydrate that are poorly digested in individuals with IBS. I have personally seen patients in my dietetic gastro clinics brought to tears (of joy) by the positive impact that this diet has had on their symptoms.
Why am I mentioning this? Well, there is recent evidence to suggest that, even in people without IBS, a low FODMAP approach can be beneficial in reducing the (let’s face it) IBS-esque symptoms that can be experienced in endurance running.
It’s early days for this research, but this could potentially be of great benefit to those runners that suffer most with their bowels on the big day, and given that we (myself especially) place such emphasis on carbohydrates as fuel, perhaps a more selective and educated approach to carbohydrate type is required.
10. Plant based diets need not be an issue
When I completed my last London marathon two years ago, I ate meat – by no means loads, and probably less than the UK average, but still it played a reasonable role in my diet.
Shortly afterwards though, I gave it up, and since then I’ve massively reduced my dairy intake too in a steady shift towards a fully plant based diet (see earlier blogs on this). Even though I’d read plenty of articles about successful plant based athletes, I was still a little apprehensive about how it might affect my running.
And the truth is, it hasn’t had any negative impact, but I would be lying if I said it didn’t need a little extra thought and planning. Meeting the high total energy and carbohydrate intakes required for endurance exercise has never been difficult, but the protein targets (typical recommendations are ~1.2-1.7g/kg body weight in endurance athletes) just require a bit more work with a plant-based diet. Plant foods are generally lower in protein than animal products, so it means that one or more decent plant based protein sources needs to be included at every meal (e.g. nuts, seeds, tofu, beans, pulses, quinoa etc). The next step is then to make clever combinations of these foods to create ‘complete’ proteins (i.e. providing all essential amino acids).
Then we need to think about micronutrients. Plant-based (and particularly vegan) diets are naturally at higher risk of deficiency in certain vitamins and minerals, and some of these (e.g. iron and zinc) might be of particular relevance to running performance. So, the first step is to be aware of the micronutrients that require closer attention (including, but not limited to calcium, iron, zinc, vitamin B12 and iodine), and the second step is to pay them closer attention! This means incorporating additional dietary sources of these nutrients (including foods that have been fortified), and resources such as the vegan society can be really helpful here to anyone starting out.
However, I also take a daily multi-micronutrient supplement to help ‘fill in the gaps’ and essentially give me peace of mind that my training won’t be impacted my any nutritional deficiencies. So far, so good.
