While sports drinks can meet your fuel and fluid needs, they’re not always convenient to take on a long run. So if you have access to water – for example at race drinks stations, or water fountains in the park – energy gels can be a more practical solution.
Energy gels are essentially concentrated drinks of about 100 calories each, and nearly all need to be taken with water so that they digest properly. How much gel you need depends on your size and how far you're running. As a general rule, you'll benefit from 30-60g (about two gels) per hour in a long run of two hours or more. How to choose an energy gel
There's a huge variety of tastes and textures, so it’s worth testing a range of gels on your long training runs to find a product that you like. Except Science in Sport's Go Gel, they all require at least a little water to wash them down. Don't try a new one on race day!