Leading article: Fitter, but fatter

If the only reason you go to the gym is to lose weight, then the good news is that you can stop going. Now. That's right, you don't have to go any more, because – according to a new scientific study – exercising will not take the pounds off.

It will make you fitter, if you really go regularly, rather than kidding yourself that you go, and it may make you feel happier. But the one effect you will have hoped for will elude you – because the bad news is that, where weight loss is concerned, there is no alternative to eating less. Or, as the scientists told the British Science Festival rather more brutally, only serious long-term dieting will address obesity.

Which is almost an invitation to take the logic further and argue that the gym, far from being weight-neutral, actually prompts a vicious cycle. The exercise makes you feel hungrier than you would otherwise have been, so you eat more afterwards; then you start stoking up on carbohydrates before to improve your stamina and enhance your various personal bests. So, in fact, it is not unreasonable to conclude that over the long term the gym risks doing you more harm than good. You could draw that conclusion – but that would be making excuses, wouldn't it?