On the table in Dame Deirdre Hutton's smart London office are two plates; one covered in raw vegetables and one laid high with fruit. The woman who has taken over the reins at the Food Standards Agency (FSA) likes to practise what she preaches.

And she has a lot to preach about. Britain, she claims, is awash with 'dietary ghettos' where people are not getting the nutrition they need. Hutton insists it is the FSA's job to change the trend. 'At the end of five years I want to see the trend in childhood obesity reversed,' she said in her first interview since taking over the new job. '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.'

At the FSA London headquarters, Hutton is surrounded by a 600-strong team who are gearing up for the next major task. Tomorrow they will launch a multi-million-pound campaign aiming to persuade people to cut out excess salt in their diet. It will be step one, said Hutton, and once in place the agency will turn to fat and sugar.

The task will be momentous. New figures today reveal that the British are eating more ready meals than ever before. In the last year we spent more than £900 million on quick-fix dinners, many of which are known to be deceptively high in saturated fat, salt and sugar. That is an extra 60,000 packs sold every month compared to two years ago. Hutton said that smarter looking packets sometimes 'looked healthy, but may not be so'.

Not that the FSA plans to cut down on ready meals - Hutton admits that she does not have the power to persuade people to revert to hours slaving over the stove.

'Processed food is here to stay,' she said. 'We need to make it as healthy as it can be. We have to recognise as a regulator 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 people's diets, Hutton is going to persuade the producers to take the salt, fat and sugar out of the ready meals. 'About 75 per cent of salts we eat come from processed food, so even small changes in that will bring about significant reduction for people.'

She will also be persuading consumers to look at the labels when they buy food and applauded Heinz's plan to display a 'flash' around the top of tins telling buyers to look at the salt levels. 'If people choose the [product] with low salt, the producer with high salt will soon get the message.'

Hutton takes her task seriously: 'It is tremendously important. If you think of one disease - the growth of type 2 diabetes - that was historically a disease of elderly people; now it's appearing in children under 10.'

She added that poor diet contributed to 100,000 deaths a year and admitted that the problem was not evenly distributed across the country. Teenage girls, lower-income groups, men in their late twenties and early 30s, and the over-50s tended to have poorer diets. Many did not even realise that their diets were lacking in nutrition. Teenagers suffered from two extremes in eating, she said: 'One is not eating enough and the other is being obese.' Very poor communities were another dietary ghetto, she added, with no access to fresh fruit and vegetables.

Young affluent men fell into a ghetto category because of their reliance on convenience food. Nearly 40 per cent of this group ate takeaways at least once a week, new research by the FSA reveals today, and one in eight don't eat fruit and vegetables every week. Others like Sheeraz Ahmed (see panel) felt their diets were healthy, but failed to account for the high levels of salt, fat and sugar in the sauces and ready meals they bought.

Hutton said she would be focusing on reaching these 'ghettos' and that the long-term answer was in schools. She described a scheme she had visited in a Newham primary school in East London where children had a Jamie Oliver-esque scheme teaching them about food. 'If I could wave a wand and do what I wanted tomorrow, it would be replicating exciting projects like that, because then you stop a generation of children from becoming overweight and unhealthy.'

The shorter-term answer is to get the industry to improve the healthiness of the food on offer. The FSA has already been successful with Project Neptune, which has seen salt in sauces and soups reduced by 30 per cent in three years. 'I think the industry are moving hugely,' said Hutton. 'We have 50 written commitments in industry on salt reduction.'

But Hutton admitted that salt was the easy one: 'Salt is an additive, you can take it out, you don't have to have it. Fat and sugar are tougher to crack, as they are often an integral part of food. '

The answer, she said, was not necessarily organic food: 'I think the important thing is to get fresh fruit and vegetable rather than to worry about whether it is organic.' Hutton agreed with her predecessor, Sir John Krebs, saying that at the moment the 'evidence does not exist' to show that organic food is nutritionally superior.

She said the FSA was keeping an eye on a big study in Newcastle into whether it was better for people and would 'keep an open mind'. In addition she said that scientific studies 'had not shown' that genetically modified foods were unsafe, but the agency would continually review its position when it came to new evidence.

The FSA is charged with the job of reducing food-borne illness and it has barely been out of the news on this subject since it was set up five years ago in the wake of a BSE scare. Earlier this year Krebs had to deal with the contamination of more than 350 food products with the carcinogenic dye Sudan I.

The pressure has remained high since Hutton stepped into his shoes - never more so than last week when an E. coli outbreak took the life of five-year-old Mason Jones in South Wales. Hutton's outbreak control team have been working hard to locate the source.

She said the FSA had 'bite' and would pursue prosecutions if any breaches of food safety rules were apparent. 'It is the prime responsibility of firms to check what they are doing, [especially] as the food chain becomes more globalised and they are getting more ingredients from less stable parts of the world,' she said.

Hutton admitted that she had set out some difficult challenges: 'It is a tall order, but we can certainly make a change.'

It's so easy to have too much

Despite his heavy work schedule and hectic social life, 34-year-old banker Sheeraz Ahmed thought his diet was fairly healthy. He was surprised when an analysis of his weekend food intake showed he was eating too much salt, sugar and fat.

Ahmed kept a food diary on Friday, Saturday and Sunday and the nutritional content of his meals was studied. He also noted down his moods.

The type of food he ate ranged from Marks & Spencer ready meals to a plate of pasta in his work canteen, curry in an Indian restaurant, burger and chips from a van at the golf course and a home-made pizza. When he described his mood as rundown or busy, his food choices were quick fixes - when he said he was relaxed he was more likely to have cooked a meal.

Over the three days, Ahmed's average fat content was 108g per day, his sugar intake was 79g per day and he has 10.2g of salt per day. They were all above the recommended daily amounts of 95g of fat, 70g of sugar and 6g of salt. On Sunday his salt intake was 17.6g - almost three times the daily allowance. A three-egg omelette with cheese and chilli sauce contained the most salt.

The results were unexpected for Ahmed because he thought his diet was 'pretty healthy', especially because it contains fresh fruit and vegetables. 'I thought I was quite good that weekend,' he said. 'If I got out, then I might eat something like a kebab. I think I eat better than most of my friends - I cook more than most of them - but I admit I never think of my salt content and rarely read labels. I do wish I had more time to cook, but I have a busy job and go out a lot.'

Ahmed, from London, said that he had seen some products with clear labels on the front of the packet. 'If they did that more often I would be more likely to look at what I was eating and be more likely to cut down.'