Britain is to be forced to ban overblown health claims made on foods such as breakfast cereals, yoghurts and children's snacks under new European Union rules.

Draft regulations leaked to The Observer reveal plans to use the European Food Safety Authority to test all claims made by companies that certain foods can cut the risk of heart disease, are 'good' for you or contain 'high' amounts of healthy vitamins and minerals. New laws will also make it an offence not to declare the amount of calories, fat and salt in food.

The regulations, drawn up by David Byrne, the European Commissioner for health and consumer protection, also suggest that the word 'diet' could be banned from food.

Commission officials made it clear that the new laws, to be placed before member states of the European Union over the next few weeks, will not affect brand names such as Diet Coke but will be used against any foods that make unchecked claims.

'This is about making sure that consumers can be confident about the information they are getting,' said one EU official.

A letter to the Commission from the Food Standards Agency, the Government watchdog, says that it supports moves towards mandatory control of health and nutritional claims.

Recent rows over food and health have focused on tinned and packaged food companies claiming their products can be part of the Government's 'five portions a day' healthy eating campaign. The £40 million campaign encouraged people to eat five portions of fruit and vegetables a day to maintain a balanced diet.

Last week Knorr foods was criticised by the Advertising Standards Authority for claiming that its Vie soups range contained up to three of the vegetable portions.

The ASA said that the high salt content of the foods had to be taken into account when considering whether a food could be said to be part of the health campaign. One serving of Knorr Vie Country Vegetable Soup contains 4.5g of salt, close to the maximum recommended daily intake of salt for an adult woman.

Heinz has also faced questions over its claim that tins of spaghetti in tomato sauce are equivalent to one portion of vegetables.

'The five-a-day message was developed by health experts to help people eat a healthier diet to cut their risk of heart disease and diet-related cancers,' said Kath Dalmeny, head of campaigns for the Food Commission, an independent British organisation. 'It should not be used by companies to promote their salty foods.'

The Commission said that many children's foods were promoted as having health benefits. Dalmeny said some Kinder chocolate bars made claims that they were 'as good as milk', and Cheesestrings, another popular children's snack, claimed each product was the equivalent of a glass of milk.

Many other foods make health claims for their products which organisations such as the Consumers' Association say are untested.

Spreads such as Dairylea are called 'light' even though they are more than 10 per cent fat. Philadelphia Light has 16g of fat in every 100g of the cheese spread. PG Tips and Tetley say that tea can be part of a 'healthier diet'. Kellogg's uses a 'healthy bones' logo on its cereals. Although the claims may be true, consumers have little way of knowing for sure.

Campaigners say that there are not good or bad foods as such and that healthy-eating messages should instead promote a varied diet.

The Byrne document says: 'Consumers have become more interested in their diet, and its relationship to health. It is important that information about foods and their nutritional value appearing on the labelling should be clear, accurate and meaningful.'

He says that 'low fat', 'fat-free' and '90 per cent fat-free' should be banned.