Countless women's magazines have claimed it's a good way to keep fit - but scientists have put the myth that sex is a good way to burn calories to bed once and for all.
A paper in the New England Journal of Medicine explains that for a man weighing 154lbs having sex for an hour only burns around 210 calories - the same as going for a walk at a "moderate" pace. Also on the list of things that aren't as good for you as you think for weight loss are breast feeding, PE and making small changes in your calorie intake.
The scientists explained:
Given that the average bout of sexual activity lasts about six minutes, a man in his early-to-mid-30s might expend approximately 21 kcal during sexual intercourse.
Of course, he would have spent roughly one third that amount of energy just watching television, so the incremental benefit of one bout of sexual activity with respect to energy expended is plausibly on the order of 14 kcal.
Damn. If only there was some other reason to have sex.