The number of people admitted to hospital in England for obesity-related reasons rose by more than 30% last year.
But NHS statistics also show the increase in obesity rates in adults seen in recent years may be flattening out.
Experts believe it is too early to say if rates of obesity are now decreasing.
The health watchdog NICE recently advised that more cases of serious obesity should be treated in hospital.
There has also been a change in the way hospital procedures are recorded, meaning more obesity-related operations make their way into the statistics.
The number of weight-loss hospital procedures (bariatric operations) carried out in England rose by 70%, from just over 4,200 in 2008/09 to just over 7,200 in 2009/10.
Eighty per cent of these operations were carried out on women, and more were carried out in the East Midlands and London than any other regions.