Fat people are being accused of deliberately over-eating so they qualify for free surgery.
Obese patients are increasingly exploiting Government guidelines restricting those eligible for NHS stomach-stapling, experts have said.
Anyone with a body mass index of 35 and a medical condition can get the surgery.
But now some primary care trusts are so overwhelmed by demand, they are increasing the limit to a BMI of 45.
The British Obesity Surgery Patients Association says some people with diabetes or high blood pressure are now deliberately fattening up to qualify.
Spokeswoman Chrissie Palmer said: ‘This is yet another process that has been turned into a postcode lottery.’
One of the PCTs to raise the bar is Somerset, where the number of stomach-stapling operations has tripled since 2004 and cost the trust £300,000 each year.
Diabetic Sig Lonegren, who weighs 20st but no longer qualifies due to a BMI of 37.3, said: ‘It’s grossly unfair.
‘There are hundreds of other people like me who can’t afford private surgery, so the message seems to be pay up or pig out.’
But the PCT insisted each case would be judged on merits, and other less drastic options offered.
Operations, including gastric by-passes or lap bands, can cost between £7,000 and £14,000 on average.
If successful, they can eliminate up to about 70 per cent of a person’s excess weight.