Britons are eating more ready meals than ever, with 31,000 extra packs being bought each month compared with a year ago. The trend is having a grave effect on the nation's health, according to the Food Standards Agency.

The worst offenders are young, urban professional men who choose the quick-fix products for convenience. The majority do not look at the labelling on the package in spite of the fact that the meals are often high in saturated fat, salt and sugar. Teenage girls, those living in poor communities and the over-fifties are the other main groups who eat too much processed food.

In the last year more than £900 million was spent on ready meals, new figures released by the FSA reveal. The most popular are Italian pasta dishes, followed by traditional British and then Indian food.

In her first interview as chair of the FSA, Dame Deirdre Hutton told The Observer the country was split into 'dietary ghettos' and taking on the ready-meal culture was her primary aim.

'Processed food is here to stay,' said Hutton. 'In that sense we need to make it as healthy as possible. It is up to us to work with what people are doing - it is no good trying to take people back to some largely mythical golden age.'

So instead of taking the ready meals out of the shopping basket, Hutton hopes to take the salt, fats and sugar out of the ready meals.

'At the end of five years I want to see the trend in childhood obesity reversed. I want the "healthy option" to be the mainstream option, and I want to get to the stage where people enjoy food more and worry about it less.'

Tomorrow the FSA will launch a campaign to try to get consumers and food manufacturers to cut down salt. Hutton said the manufacturers had already made huge steps. 'We have got 50 written commitments. Even small changes will bring about a significant reduction.'

Martin Paterson, deputy director-general of the Food and Drink Federation, said Hutton was 'pushing at an open door'. He said the federation had carried out a survey of the 20 biggest brands including Heinz, Nestlé and Kellogg's, and 97 per cent of products (worth £33 billion in UK sales) would have full nutritional information by the end of 2006.

'There have been changes to the composition of food - taking out salt, fat and sugar,' he said. 'But you can't get away from the fact that, if you take sugar and fat out of a doughnut, it stops being a doughnut. It is dangerous to focus just on composition.'

Food campaigners believe there is much to be done. Jeanette Longfield, of Sustain, an alliance for better food and farming, said: 'Why is it that the healthy option is a niche market? If it tastes as good with less fat and salt, why is that not the norm? Ready meals are nutritionally low in value.'