Using energy gels for training is an absolute mugs' game. After much experimentation with running food, including various gels, I've found that the best thing for me is bars of jelly. One 130g bar of Hartley's packs in nigh on 400 calories, and costs about 40p. Not sure whether or not they've got fancy branched techno-acids or any of that stuff, but I do know that half a bar every hour or so sees me right in long fell races.
Joss Naylor's quoted in that article saying that he just ate normal food on his runs, so if it's good enough for him...
Edited: 31/08/2012 at 15:14