A quarter of Kiwis are now obese and the trend towards supersizing shows no sign of slowing.

The Ministry of Health's 2010 social report shows that 25% of the population aged 15 and over is obese, defined as a body mass index of 30 or more. The rate in 1997 was 19%.

A poll out last week revealed every second respondent wanted to lose weight this year, but the statistics on dieting show most will fail. Businesses are betting on the trend by producing larger sizes in clothing and even hospital beds and coffins.

Waikato Hospital dietitian Helen Wallwork says 95 out of 100 dieters will not only fail to keep the weight off, but will end up putting it on.

"As a profession we're not very keen on dieting. We'd prefer to see people adopt more healthy eating patterns."

She said that meant eating more fruit and vegetables in a good colour range, and remembering "chips are not a vegetable".

The problem is so great that the hospital's latest addition is the country's first purpose-built emergency room for large patients.

Waikato's new emergency department opens next month and includes a room with a strengthened ceiling to cope with a hoist capable of moving 200kg-plus patients.

"It's based on need," says Wallwork. "It is very difficult to mobilise and transfer patients when they're very heavy, not to mention dangerous for staff."

The hospital has also recently invested in several new larger beds for people who weigh up to 280kg, compared to ordinary beds designed for people weighing up to about 170kg.

And if the trend is for ever-increasing girth, there are consumer moves to match it in Britain, where Oxford University researchers found the average man is about 7.7kg heavier today than 10 years ago.

More than 25% of British women are now size 18 and over, and clothing businesses are adapting by offering a wider range of clothing. And when the end comes, funeral directors and cemeteries can supply bigger coffins and larger plots.

One size may no longer fit all, but one supersize comes close.