I’ll refrain from turning into a collective mum here and start nagging everyone about smoking - we all know by now that it’s one of the dumbest things you can do.

But I do want to draw everyone’s attention to this new study , which shows that not only do teen girls seem to smoke at a much higher rate than teen boys, smoking does not appear to have any effect on their weight. It does appear to have an effect on the weight of boys - but that seems to be because boys experience their growth spurts much later than girls do, so smoking in their teens can have a much greater impact on their growth and height.

A widely-held belief goes that smoking keeps the appetite down, and therefore women who smoke have an easier time keeping the pounds off. So many women apparently are reluctant to kick the habit, prefering to poison their lungs rather than thicken their thighs.

But this study says there’s no basis for that belief, and our misconceptions about smoking and weight could be doing us a lot of harm.