Running on empty - how gels can give you that timely energy boost

Now that it's hitting the business end of the training programme and the mileage has increased (especially the longer runs) the importance of energy gels comes in to play. If you have never tasted these sweet delights before, now is the time to experiment and see which one suits you. Trying a new energy gel on marathon day can be a disaster and have devasting results.
Training for my first marathon, I wasn't aware of the postive effects of these gels and sought energy boosts from alternative sources like jelly sweets and energy drinks - this was not a wise decision for me to make as I often experienced what runners call "jelly belly" and a sugar overload which accompained with a sickly feeling in the stomach often made those last few miles pretty unbearable.
Hindsight however, is a wonderul thing and I have since graduated to taking on energy gels and just drinking water to hydrate which gives me that well needed boost without that upset stomach!
What gel you choose is entirely up to you but personally I tend to go for a diluted gel that may not contain as much caffeine as others, therefore being that bit gentler on the stomach yet still giving you the boost you need.
To this day, I'm not sure if these gels are a placebo or not but about a mile after taking one, I tend to get a well needed boost both physically and mentally and can kick on again on my merry way!
When to take these gels is another question that will be answered by the practice run, as well as when taking water on board is needed also.
I tend to take one every 6/7 miles on race day to give myself every chance - there's little point taking one on board when heavy fatigue has already set in.
Most importantly, these long practice runs are the correct time to discover the joys of these gels and there undoubtable benefits, not on the day when it just may be too late!