To supplement or not supplement during the course of a marathon is all I have been getting asked since Mark Armstrong's column last week.

With just a couple a weeks to go before the Manchester Marathon he is rightly so concerned that he gets everything right going into his big race and that includes his nutritional requirements during his last couple of long training runs and of course the marathon itself.

However, I have also had to tell him that first and foremost, getting it right means getting the training right and most importantly getting the pace right on the day above anything else.

Whilst nutrition is indeed so very important in terms of ensuring that all our needs in respect of energy and recovery requirements are met by way of eating the right foods, supplementation whilst running is something else.

Some of the comments on Run Anglia's Facebook page last week after Mark's column certainly showed that a lot of thought goes into this and by runners of all standards too.

To really do this subject justice, I would need a lot more space than I am entitled to, so trying to keep to the basics, do supplements make a difference when it comes to performance and should we also become reliant upon them if we want to achieve our very best?

At the very sharp end, I really don't think so.

For those running closer to three hours and of course those who are out there for four hours or more, then yes I am sure they help along with supplements of a little more substance particularly for those in the latter bracket.

My main concern when talking to Mark though was more down to what he possibly saw as his reliance upon consuming gels on route.

The interaction and tips on Run Anglia were excellent, but it did also cause me to wonder how it would affect some of these people if for whatever reason they had to run without having these supplementary aids.

How would it affect their mindset when standing on the start line if for whatever reason they had left their gels behind and none would be available during the course of the race?

Would it immediately cause their thoughts to turn to creating some negativity in respect of their goals and targets and then perhaps when going through a tough period, their mind immediately switches to foreseeing a struggle ahead due to the non-availability of supplementation?

I understand this because I always religiously drank two cups of black coffee an hour or so before racing.

I would always mix and take a bottle of cold coffee with me just in case none was available. I would even drink it in warm weather when I knew it could also be detrimental to performance due to its diuretic effects such was my reliance upon it.

When we run our body uses two sources of fuel – fat and carbohydrates.

However, fat becomes less efficient by way of oxidation when working at a higher intensity.

This is not just applicable to the 5k and 10k racing speeds either, but also in a marathon particularly when pushing and looking to maintaining a pace for what might be a best performance.

Therefore it is carbohydrates (stored in the muscles and liver as glycogen) which goes to making up the body's preferred fuel of choice.

I always look at it as having two fuel tanks, one large which can last for a long time, but is slow to use and one which is more high octane, but a much smaller tank and therefore the harder we work the quicker it runs out.

In a nutshell approximately 90 minutes at half marathon pace and two hours in a marathon. For the very elite, the likelihood is due to their natural genetics and highly trained bodies, they will cross the finish line in just over two hours for which I doubt most of them use anything other than water or electrolyte drinks on route and mainly for hydration purposes. For those amongst the masses though, this is a different kettle of fish.

So what do these gels do?

Firstly they raise blood sugar levels for which you really should only take them during exercise or immediately before.

If you take them outside of exercise or let's say an hour before, then as per normal the body will look to regulate itself and in this instance there will be a release of insulin to reduce the excess sugar in the blood stream for which you are likely to then find yourself feeling flatter than you were before the short sugar rush.

With regards to providing energy the idea is that the gel will provide energy during the run to spare some of the stored glycogen, but you could also further debate that it is still very little due to absorption rates.

There is also some evidence to suggest that the sugar in the gel gives the brain a quick nudge and wake up call which can be of great importance as the mind starts to get tired during the latter stages of a long run.

You will also need to be aware of taking too many of them and bear in mind that body size is a factor too.

It is usually suggested one gram per kg of body weight per hour i.e. if you weigh 65kg, then 65 grams per hour. At the same time look to consume them with water particularly in warmer and humid conditions or go for the gels which are designed to be isotonic. There are also gels which contain caffeine too which can help to give an added boost in the later miles, but once again be aware that if the temperature is warm, then caffeine can lend itself to causing further dehydration.

Needless to say, there are so many other supplements other than gels which are advocated by many who have taken part in endurance events such as sugary sweets, cereal bars and savoury salty snacks, but your stomach will also have to work extra hard to digest all these products which could in turn lead to a number of issues.

My personal advice is to be totally confident and focus on all the work which you have put into your training, carbo load for two to three days prior to the race and only use supplements which you know works for you having used them during training or previous races with no ill effects. Definitely do not experiment on the day though.

Emma Risbey, who is a top local athlete and expert in nutrition and is currently working with many top international athletes and triathletes, very much echoed what I have already said when speaking to her.

'I think gels serve a good purpose, especially with electrolytes and caffeine during the last few miles, but they should not be used for the first time on race day.

'Stick to a well-timed plan such as every 45 minutes and don't take in all at once to reduce the risk of a stitch. Also sip water at timed intervals too as dehydration is far worse than glycogen depletion,' she said.

Incidentally I never ever used a gel in any of the many marathons I ran in. The first time I came across them was in 1987 and whilst I did experiment with them in training, I preferred to just rely on water and the electrolyte drinks which more than likely contained far less calories by way of energy during racing.

However, this also made me wonder if I would have been able to run faster times if I had given more thought to gels and race supplementation and even more interestingly it did also make me wonder how much difference it would have made to the real greats and heroes of mine back in the day.

I asked a top UK and world class marathon runner from the 1970s what his opinion is and hence why I am leaving the last words on this subject to him.

'That's a really good question, particularly as the number of sub 2:20 marathon runners in this country have been on a decline during the last 30 years for which I would have to say that either gels don't work or perhaps people have become more accustomed and reliant upon looking for something which comes far more easier than banging out a few more hard training miles. I will leave you to make up your own mind on that one. At the same time, if there were gels around in my day and someone said if you eat this gel at half way it will give you an energy boost in the second half of the race and it is totally legal, then I would have to say I would be stupid not to have tried it out in training and then all being well used it on race day. I doubt I would have admitted to it making me run any quicker though.'