Tuesday, 10 August 2010

Race Nutrition - Is More Always Better?

Hi Again,

Thanks to those of you who have left a comment.  It is always nice to get some feedback on what I write.  Following the Lakeland 100 race I spoke to a number of runners about my race nutrition, in addition, two comments left on my previous post made reference to my race nutrition, so hence the title of tonight's blog; "Race Nutrition - Is More Always Better?"

Since the Lakeland 100 race I have spent a few days in the Lakes District with my family, and now I am again on holiday with my family down in the Channel Islands, on Herm Island, the smallest of the Channel islands.  There is a track around the entire island, and on Saturday was the Herm Run consisting of one undulating lap of the island, a grand total of 2.82 miles.  I ran with my youngest son Chris, and finished in 46th equal place in a time of 27:49.  Robert my other son and Frances my wife both finished ahead of us in times of 25:24 (30th) and 27:01 (42nd) respectively.  If you are looking for a great place to relax and take it easy after running 103 miles, or to do a low key friendly race, then Herm Island is a great place! 

In between my two holidays I was back at work at the University of Brighton and a number of colleagues were commenting about my UltraStu blog.  They were rather critical at the lack of evidence to support the statements I make.  The need to provide evidence is something that we really drive home with the students, and they were rather disappointed at the lack of references I provide.  I am well aware that some people will consider the lack of references within my posts as poor writing, however, my blog is not supposed to me an academic piece of writing.  So when it is easy for me to provide a reference to support my comments I will, e.g. in my posts on running economy.  However, on most occasions my posts are based on my own personal experiences, or material I have read in academic journals in the past, but I just can't remember the author and source!  So if you are like my colleagues and wish to see references, then tonight's post you are going to be overly disappointed.  Being on holiday I don't have any access to the academic journals, and actually I can't really be bothered.  So tonight is straight from my own 'gut feelings'!

In last week's post I made the comment that "Ultra trail running is so TOTALLY DIFFERENT to trail marathons".  The massive difference is due to the much lower intensity one races at in an Ultra, especially an Ultra lasting 24 hours, in comparison to marathon race intensity.  Looking at my heart rate data for leg 8 of the Lakeland 100, the middle leg.  The leg lasted 2 hours 6 minutes, and my average heart rate was only 124 bpm, with a maximum during the leg of only 138 bpm.  Massively different to say my heart rate for the South Downs Marathon back in June, 2 hours 55 minutes of  running, and an average heart rate of 171 bpm and a maximum of 182 bpm!  So this much lower race intensity not only affects the type of training that is most appropriate for ultras, but also affects the most appropriate race nutrition for ultras, as I will later explain, this is also different from marathon racing!

Before I expand upon this, with details of what I consume during the Lakeland 100, it is time for some more Millsy Memories!  Marathon Number 3 - Christchurch Marathon - June 1984.

Those of you who have read my post titled " Marathon Number 1 - April 1980 " will know that I achieved my goal of running a sub 3 hour marathon on my first attempt.  Well, come four years later I set myself a new goal, a sub 2 hour 30 minute marathon.  I decided upon the Christchurch Marathon, which used the same course as that used for the 1974 Commonwealth Games marathon, which was won by the English runner Ian Thompson in a very quick time of 2:09:12, the second fastest marathon time ever, in 1974 (see race history), so it was a quick course.

In preparation for my sub 2:30 marathon I ran a training marathon, the Mangaroa Marathon, just a few miles from where I lived in the Hutt Valley, eight weeks prior to Christchurch Marathon, finishing in 6th place in a time of 2:45:32.  At the time I thought that running a training marathon was the ideal thing to do.  At the age of 21, I didn't know any better.  Now with a wee bit more experience I would now state that you probably don't need to run a training marathon in preparation for a marathon, but that is another topic.  Lets get back to marathon number 3 and race nutrition!

Come race day, a rather cold morning on a June winters day, I am well prepared, totally focused to achieve my goal.  My plan is to run at a consistent even pace (yes a different strategy to ultra racing as the event is so different), 3:30 per km, which gives a 2:27:41 marathon time.  So I have a wee bit over 2 minutes 'up my sleeve' to slow down during the latter stages, in preparation for the so called "marathon wall", which I had read about in New Zealand running magazines.  I had also read in running magazines (at that time in 1984 my only source of running information) the need to carbo load, so I adopted this approach in the last few days as best I could, basically eating loads of carbohydrate food.  I didn't adopt the depletion stage at the start of the week which was the traditional approach proposed by Bergstrom (1967) and frequently used by the great runner Ron Hill in the early 70s.  Now if you want to read two good books, I recommend you read Ron Hills' autobiographies. I found them absolutely superb, although some people I know found them a bit excessive.  If you love running and racing, then you will love his books.  He had so much too write, he published them himself, around 450 pages each book, as every publisher said he had to massively shorten it.  Ron Hill's attitude of 'doing it his way', not following the norm, is what I liked so much about his approach to running described within his books.  Sorry, I just got distracted again, lets get back to Christchurch 1984!

So the marathon is going well, I'm 15 seconds up on schedule at 5km, and pretty well stay bang on target 3:30 per km, and at 35 km I am only 5 seconds down.  And then, 'the wheels fall off'!!!  As if instantly I go really 'woozey' in the head, I feel really tired, can barely keep my eyes open, and during the next 7.2 kilometres I lose all of the time I had gained on my 2:27:41 schedule and cross the finish line extremely, extremely disappointed in a time of 2 hours 30 minutes and 40 seconds.  I am so disappointed it is over eight years before I run my next marathon!

So what went wrong???  It was simple, I simply ran out of carbohydrate, I suffered from hypoglycemia, i.e. low blood sugar.  Back in 1984 in New Zealand there weren't such things as carbohydrate gels, and water was the only drink available at water stations.  The running magazines didn't mention the need to take on carbohydrate DURING the actual marathon race.  They only highlighted the need for carbohydrate in the days before the race! 

But it wasn't until three years later, when I was down at Otago University studying for my Sports Science degree that I got really really angry!  I still have anger now when I think back to it.  There I was in the University library reading some academic journal articles on carbohydrates and endurance performance where I read that way back in 1982, two years before my Christchurch Marathon, the South African Athletic Association made it compulsory for marathon organisers to provide carbohydrate drinks at drink stations during a marathon.  Why didn't the New Zealand Athletic Association have the same requirement?  Why weren't the running magazines providing this essential bit of information that you had to consume carbohydrate DURING a marathon?  I was more than capable of running sub 2:30, but without consuming carbohydrate DURING the marathon, it makes it rather difficult, as the body has only limited stores of carbohydrate, and running at marathon pace, at around ones lactate threshold a runner typically will deplete their carbohydrate stores before reaching the 26 mile mark!  I guess from that day in the library onwards, I took the approach that just because it's the norm, e.g. running a marathon on water only,  it doesn't mean it is the correct thing to do.  I took the approach that I will always question things and try to find the answer, and if need be, differ from the norm and do it my way! 

So how does race nutrition differ between marathons and ultras?  As mentioned above it is all down to the intensity you race at.  Although I lecture in Sports Science, I haven't taught any physiology or nutrition modules for a number of years, so I don't have the references at hand.  However, I have read alot in the past and hopefully my interpretation isn't too far 'off track'.  If any sports scientists or physiologists out there wish to confirm or contradict what I state with evidence/references, please feel welcome to do so by leaving a comment.

So time for some simple physiology.  The body needs fuel to run, typically either fat or carbohydrate (ignoring protein).  How much of fat or carbohydrate is determined by the intensity you run at.  I could expand on this with some biochemistry, Krebs cycle, ATP etc, however I wont.  If you are interested in more detail, have a look at an exercise physiology book such as McArdle, Katch and Katch.  So the higher the intensity the more carbohydrate is used.  The only problem with running at a high intesity and using more carbohydrate is as mentioned above there are limited carbohydrate stores within the body, whereas we have pretty well unlimited fat stores.  It is possible to estimate the ratio of fat and carbohydrate consumed while running, referred to as one's respiratory exchange ratio (RER), by simply measuring the amount of oxygen and carbohydrate contained within one's expired air, usually collect in a large bag called a Douglas bag during a lab test.  As there are limited carbohydrate stores, there are various strategies used during marathon running to help you to not run out of carbohydrate, such as carbo loading prior to the race, and consuming carbohydrate during the race.  One other strategy to help preserve the limited carbohydrate stores is to try to train your body to consume more fat.  Although I haven't found any research to confirm the best training to achieve this, it is speculated that by training at an easy pace, below lactate threshold/turnpoint, it enhances one's ability to burn fat.  Hence another reason why I stated in the What Training is Appropriate post that "To run faster in ultra trail races, train slower!"

I received an e-mail a month or two back asking me whether I consume carbohydrates during my training runs.  Apart from when I do excessively long runs (more than 22 miles), which isn't very often, usually only on a unique occasion, I never consume carbohydrate in training.  I hadn't got around to replying to the e-mail as I was hoping to find some research confirming my 'gut feeling' that consuming carbohydrate during training isn't wise.  About the year or two ago I was chatting on the phone to one of my ex-students who was completing a PhD at Birmingham University under the guidance of Asker Jeukendrup, who is a bit of a sports nutrition guru.  My ex-student Carl Hulston was investigating this very issue.  His hypothesis, which was in agreement with mine is that one of the aims of long endurance rides or runs is to improve the body's ability to utilise fat, and to feed on carbohydrate during training simply negates this 'learning process'.  Carl has been working overseas recently, but is coming back to the UK in September, so I'll give him a call upon his return and keep you updated on what his PhD research found.  Until then, I will continue to rely on what feels right and seems to work for me, i.e. no carbohydrate feeding during training.

But what about whilst racing?  As mentioned above, for marathon running, you definitely need to take on board during the race carbohydrate.  Extensive research has shown that what is really important is the concentration of this carbohydrate, which should be around 6 - 7%  Therefore it is ESSENTIAL that if you consume a carbohydrate gel typically around 25 grams, you MUST also consume around 400 millilitres of water, i.e. two full cups of water, not one or two mouthfuls splashed over your face!  The problem with not consuming water is that the high carbohydrate concentration within your stomach will cause water to be drawn out of your body into your stomach, to dilute this high concentration.  One major concern during racing is getting dehydrated, consuming high percentage concentrations of carbohydrate, such as jellie babies significantly increases the risk of dehydration, as the water is drawn into your stomach!  And with dehydration performance rapidly decreases!

One other problem that may arise when consuming high concentrations of carbohydrate (sugar) is that you may get a large release of insulin.  One of the functions of insulin is to lower one's blood sugar level, return it back to normal.  As long as your intensity is sufficiently high during racing, this insulin release is inhibited, so you will not get an insulin 'overshoot', resulting in excessively low blood sugar levels.  However, I have a real concern that during ultra running, because the intensity is so low, that this insulin overshoot may occur.  Where the blood sugar fluctuates from a massive high after consuming the high concentration of sugar, which is then followed by a large drop in blood sugar levels, due to this overshoot!  Hence my main focus during ultras when consuming carbohydrate is to ensure that the percentage concentration is never more that 6%, so I am always consuming water whenever I take on board carbohydrate.

Now getting back to how the ratio of carbohydrate:fat utilised is determined by one's race intensity.  At a heart rate for me of anything less than say 145bpm, I find that my body only uses minimal carbohydrate and burns loads of fat.  During my three day recce run of the Lakeland 100 course back in May, whilst actually running, disregarding breakfast and the evening meal, during the entire three days running I only consumed 5 Cliff bars in total, (two on days 1 and 2, and one on day 3) and towards the end of day two I also a handful of chocolate covered coffee beans as I started to get a bit tired, and that was it!  I didn't need any more carbohydrate, as the intensity was so low, so a good opportunity to burn some of my excess body fat!

Now come race day, yes I start at a really fast pace, average heart rate of 163 bpm during leg 1, so burning loads of carbohydrate, so I consume a carbohydrate gel, then on leg 2 I eat a Cliff bar as the average heart rate drops to 155 bpm.  As the race progresses, my intensity decreases, so I consume less carbohydrate as my body is not burning it. As it so happened during the Lakeland 100 during the second half of the race, I was running at an even lower intensity than during my recce run.  So while racing I simply thought, if I only need a few Cliff bars back in May, I don't need any more carbohydrate now.  However, what I do need during the Lakeland 100 race is caffeine.  I find that during long ultra races, I begin to get mentally tired, which corresponds with overall tiredness, as the body and mind are one.  Caffeine is excellent at masking this tiredness, so I frequently consume cocacola during ultra races.  Listed below is as far as I can remember what I consumed during the race. 

As mentioned above, one thing which I have found that works for me during ultra races is consuming coca cola.  Coke typically has a 12% carbohydrate percentage, so I ensure that I dilute the coke 50:50, reducing the concentration to the ideal 6%.  During the Lakeland 100 at those checkpoints that had coke I therefore consumed two cups of coke and two cups of water.  One can do calculations to work out how many calories (kilojoules) one burns while running at different running paces.  I haven't bothered to do the calculations, but all I know that to run 103 miles, it isn't actually as many calories as one would expect!  So is there really a need then to eat excessively during a 100 mile ultra?  I think not.  Why eat more than you need?  What benefit does it give you? 

The main benefit is the self belief that it will make you run better, give you the energy to go faster, to keep on going.  As I mention in other posts performance is largely determined by ones self belief, so continue consuming large amounts of carbohydrate/food during races if the self belief improves performance.  However, is it possible that consuming loads of carbohydrate/food may actually hinder your performance physiologically.  Does having this food in your stomach draw blood away from the muscles to start digesting the food?  Does the high concentration of carbohydrate in your stomach draw water away from your body into the stomach, making you dehydrated.  Yes positive self belief may be useful, but if there are actual physiological negative consequences, then the overall effect may be a decrease in performance.  What is the answer?  I don't know, but for me, I know what works from many races of trial and error.

Well, another ultra endurance post.  I didn't quite finish it last night.  But as it is currently raining outside at the moment, the beach has been delayed until the sun comes out!  I hope you find my details on my race nutrition interesting.

Time to sign off with some 'words of wisdom'.  "Always question what you have been told, what appears to be the norm.  Try to find the answer from whatever sources are available.  If you can't find THE answer, go with what feels and works best for you!" Stuart Mills (2010)

All the best with your fuelling,



  1. Really interesting stuff Stuart, thanks for posting.

    When I started ultras (all of three and a half years ago!) the wisdom seemed to be "you have to replace what you're using" so we really worried about "running out of fuel". More recently I found a common theme to be "you burn about 100 cals a mile, try to replace 100 cals an hour" which seemed more sensible. I'm not a nutritionist but I was (once!) an engineer, and by my calculations the 100cals a mile seems to be a reasonable rule of thumb. Your weight obviously influences this, but not many ultra runners are very heavy, speed and height gain too but not as much as you might think.

    So in a 100 mile event you're going to burn around 10,000 cals. From your post I reckon you consumed something under 2000 and it was certainly good enough for you - over a day you can clearly take that deficit OK. I stopped at just under 90 miles, by when I had consumed about 4200 cals - and because I was going so much slower than you (and also I guess because I'm 20 years or so older) I probably should have consumed LESS than you overall. My general takeout from all this now is that one shouldn't worry too much about forcing down food as "fuel", natural hunger should give you enough. I think modern thinking on hydration is "drink when you're thirsty", so maybe you could add to this "eat when you're hungry".

    Looking forward to trying this out in the next event!

  2. Very interesting Stuart. I am a believer in little and often for food and to a lesser degree liquid intake. To me it makes sense to try and replace required energy (difficult to ascertain without some luck) at the same rate as you use it up. I tend not to eat much at the start but start to eat more towards the middle, and less again near the end. Towards the middle of a long ultra your reserves of carbs (in theory) will be low. So a steady topping up seems logical. Near the end it is probably less necessary as, if you have got the intake right you should have enough in the tank anyway.
    I agree with your training strategy of not using carbs. I took it further and limited liquids. My theory being that when you race you will have plenty of both available and you will use the energy and fluids more efficiently.

  3. Hi Andy, Alan

    Thanks for the comments. With regards to the need to replace the fuel you have been using, I think that this isn't necessary during racing. If you are running at a reasonably low intensity you will be burning a lot of fat, which most runners have plenty of, including myself! So there isn't any need to replace this fat! The aim during racing is to try to keep the blood sugar topped up, so not using so much of the limited glycogen stores, but as I mention in my post no need to 'go over the top' in terms of the amount of carbohydrate one needs to consume.

    I also believe little and often is the best approach with regards to consuming fuel during racing, although I always keep on taking on carbohydrate right through to the end of the race, even with only say 20 - 30 minutes of a race to go. The reason for this is based on some intersting research a few years back, (sorry still on holiday so I don't have the references!) that investigated the effect of only swishing a carbohydrate drink within the mouth, not actually drinking any carbohydrate. The effect was that just having the carbohydrate being detected by the taste buds will improve performance, it doesn't even have to be swallowed. The rationale for this is that the taste buds send a message to the brain to say "its all okay you can run harder as there is some carbohydrate on its way", resulting in the ability to run faster. Hence why I consume carbohydrate right to the end.


  4. I see. So the fat stores are used, but the carbs need to be used to supplement the using of the harder to reach fat store. It makes sense but I don’t know if I could trust to eating as little as you in an ultra. Although I am thinking of eating less next time as your theories seem sound.
    I suppose the best training for an ultra, based on this, is to try and make yourself as efficient at burning fat as a fuel as possible. As you say long slow runs will do that. Would Fartlek and tempo runs?

  5. Hi Stu, Some very good comments here ref nutrition during ultras. I was a 'victim' of science for years, before I developed the confidence to trust my own instincts and take less of everything. One of my favourite quotes is this:
    "It's not how many calories you can consume during an event, it's how few you can consume without slowing yourself down.
    What you want is something small, something that puts just the right amount of calories back in and does not waste your body's energy trying to digest more than you can actually use.”
    Bill Nicolai, American triathlete