According to government figures, the NHS in the UK spends around £85m a year on gastric bypass operations.
(Between April 2006 and March 2012, the NHS carried out 18,577 gastric bypass and 7,650 gastric band operations. These weight-loss operations, sometimes called 'bariatric surgery', work by restricting the amount of nutrients that can be digested and absorbed. Of course, people could always try simply eating less.)