GELS – the good the bad and the ugly

GELS – the good the bad and the ugly

Gels what are they good for?

A detailed viewpoint by Coach Jonathan Worswick

Be careful using gels. I know this sounds a bit drastic considering their popularity but consuming a gel without understanding the consequences can ruin your race.

Don’t use the upcoming Western Sydney Marathon to experiment either, sound advice is to practice Gel use and give your body time to adapt to using them as a fuel. Say you are going for your first sub-3-hour marathon, you’re trained up and ready. You’re 35km into the race and doing ok but it is getting harder to hold your goal pace of 4:15s. You think I need a quick kick to keep me on track, now’s the time to take that gel I’ve been carrying. Quickly you chug it all down mid aid-station. Another km or two and you are feeling ok and holding pace, great. Then BANG! Your legs feel like lead, your pace drops to 4:40’s, you feel nauseous, the dreaded Gastrointestinal (GI) distress, your 3-hour time is gone.

What just happened? It may well have been that gel you just chugged down.

Why? Firstly, most gels are intended to be taken with water. There is a reason for this – gels have a high carb concentration (on average 360Kjs/gel with 70-75% being concentrated carbs) which means higher osmolality. Diluting the gel assists moving it out of your stomach and into your gut where it can be absorbed for energy.

I’ll bet you don’t usually take it with a decent mouthful of water, do you?

And there’s more! Most gels contain a glucose/fructose mix and maltodextrin. Fructose takes longer to absorb and can draw water into your gut to try and dilute it, which can cause GI issues. What about maltodextrin? More easily absorbed (lower osmolality) compared to simple sugars like glucose, fructose or sucrose, but it can still have an effect on the small intestine causing a delay in absorption into energy.

Should I stop taking gels? Not necessarily. Gels, when used correctly, can be very useful. Using gels diluted and/or with other race foods may work for you. A controlling sugar “hit” at the right time and place may be just what you need.

What gels should I use?  Check the ingredients and focus on what you like and need. Some gels contain caffeine so if you don’t regularly consume caffeine this can have a significant impact, good or bad.  Check the types of sugar included and all other ingredients.  Find a brand and flavour that works for you.


  • Take a small flask with 1-2 gels diluted with water. The flasks are small enough to fit in your shorts pocket or a small race band.
  • Look for a more natural gel. Usually, they contain dried fruit, evaporated cane sugar or agave nectar. Cane sugar is fine as it is sucrose, whereas agave-nectar can be harder to digest due to its high fructose content.
  • Why not try glucose tablets (~5cals/25kJ’s per tablet) as an alternative to give you that sugar high or even a handful of jelly beans or dates/sultanas (juicy ones from the health store)? **why glucose??
  • Never try a new gel (or any nutrition) on race day. Always train with the nutrition you are planning to use when you race.

The recommended amount of Gels for each Race to use for the Western Sydney Marathon

  • 5k – 1 30-40 mins prior to start gun
  • 10k – 1 30-40 mins prior to start gun
  • Half – 30-40 mins prior to start gun, 1 at 10km marker
  • Marathon – 30-40 mins prior to start gun, 1 every 45 Mins.


Finally; we are all different. Whether it is our build, fitness level or how our body absorbs the energy we put into it. Also, each event will have its own environmental differences, hot and humid, cold and wet.

Take these into consideration by practising with the stuff you put in your mouth in similar “stressful” situations e.g. a long marathon paced run, that mimics your race environment/pace.

and remember to stock up before race day as it is fast approaching, don’t leave it to the last few days to get the flavour or type you have been using as the Western Sydney Marathon is just around the corner. Happy running Coach Jonathan.

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