New figures show a year-on-year increase in morbidly obese patients being prescribed last resort treatment, with the number leaping from 49 in 2003 to 185 in 2007.

The statistics were released by Nicola Sturgeon, the health secretary, in a response to a question lodged in Holyrood by Tory health spokeswoman Mary Scanlon MSP.

Ms Scanlon said: “This rise in weight-loss surgery is a consequence of not having health visitors doing checks on children, it’s a consequence of poor and confusing food labelling and it’s a consequence of this problem not being picked up in children at school and of parents not being given the help and support they need.”

A Scottish Government spokeswoman said: “Surgery for obesity is rare and only completed when everything else has been tried but failed to achieve weight loss for a severely obese patient.”