Seven of the biggest chains are making their menus healthier by reducing fat and salt in snacks and drinks

Britain's biggest coffee shops have promised to take salt and fat out of sandwiches and cakes eaten by tens of millions of customers as part of a new campaign against junk food launched today.

The Independent has learned that seven chains – Starbucks, Costa Coffee, Pret A Manger, Caffè Nero, Eat, Greggs and BB's - have made public commitments to change hundreds of products that contribute to heart disease and obesity.

The moves, to be officially announced by the Food Standards Agency today, could improve the health of tens of millions of customers who are unwittingly consuming high-calorie foods. At present nutritional information is not displayed in coffee shops' "freshly made products", meaning that many customers are unaware of the threat posed by sandwiches, snacks and pastries loaded with salt and saturated fat.

A large coffee and a muffin at Costa Coffee or Starbucks, for instance, can contain more than 1,000 calories – around half of an adult's recommended daily intake – while other chains such as Pret A Manger have been criticised for selling mayonnaise-heavy sandwiches.

Among the commitments are that:

*Pret a Manger will for the first time display calorie counts

*Starbucks review its range and change at least 10 best-selling products

*Eat will reduce salt in soups and make sandwiches and salads healthier

n Costa Coffee will sell only food rated healthy by the FSA

n Greggs will remove hydrogenated fat, artificial colourings and flavourings from its pies

Each commitment given by the chains will be reviewed by the FSA every six months as part of a rolling programme to transform the health of coffee shops. The agency is targeting the £1bn-a-year coffee-shop business in an attempt to reform takeaway and restaurant meals, which now account for one quarter of the food we eat.

Officials are concerned that improvements made by shops and supermarkets to reduce salt, sugar and fat will be undermined if customers get a taste for more unhealthy food at cafés. Nutritionists from the FSA have been working with the chains to show them how they can cut harmful nutrients by employing simple techniques like switching from full-fat to semi-skimmed milk and cooking chicken without skin.

Changes are likely to be introduced gradually to ensure that customers do not notice a change in the taste of their favourite snacks and sandwiches.

In an interview with The Independent, the FSA's chief executive, Tim Smith said: "Behind the scenes there's quite a bit of reformulation work going on. Whether the sandwich shop chooses then to brag about that or make it a marketing advantage, I don't think we're so interested in. But some of the changes will be invisible, so your BLT (bacon, lettuce and tomato sandwich) might be a BLT, but it might have lower-salt bread, low-fat mayonnaise and less fatty bacon."

Among the biggest changes customers will notice is the trial beginning in some Pret A Manger outlets next month, which will see calorie counts displayed on the price tag below sandwiches.

Many of the chains say they have been quietly removing fat and sugar from their products for the past two years. Starbucks said it had doubled the number of healthier-choice foods in its stores in the past two years. In January this year, the US coffee giant cut the amount of salt in its sandwiches by 14 per cent. Costa Coffee, the country's biggest coffee shop chain, has reduced fat by using tuna canned in water rather than oil.

Pret A Manger is talking to its suppliers about cutting the salt in its Irish cheddar cheese, while the chain has already dropped its pecan pie and replaced it with a Bird Bar full of seeds, while replacing farmed with wild salmon has halved fat.

The sandwich chain's food and communications director, Simon Hargrave, said: "Instead of a stick approach where you are exposed for too much salt in one sandwich they're [the FSA] saying we can change things in small amounts over time. It's a much more practical approach. A few years ago we would have signed off a sandwich without even thinking of the salt." The campaign – backed by the Government – comes amid predictions that 60 per cent of men, 50 per cent of women and 25 per cent of children will be obese by 2050, unless action is taken.

The Public Health minister Dawn Primarolo said: "These commitments will help people make healthier choices and will go some way towards our aim to make healthy food the norm."

Many products, though, will remain treats, such as Pret's All Day Breakfast, with almost 600 calories. "You should only be eating one once or twice a week," said Mr Hargrave.

How the chains will change

Caffe Nero: 360 stores

Before A mocha with whipped cream has 326 calories; a mozzarella and pepper panini has 476 calories.

After Review product range and reformulate where possible; start to cut salt to meet FSA 2010 targets; offer a healthier choice in every category; cut fat in sandwiches; introduce new lower-fat recipes.

Greggs: 1,100 stores

Before Bread and pies with high fat content and artificial colours and flavours. An analysis by Channel 4 last year – disputed by Greggs – found 69 per cent of Greggs sandwiches earned an FSA "red light".

After Make nutritional information available to all customers; remove all hydrogenated fats from own-made products; remove all artificial colours from own-made products; by June 2010, remove all artificial flavours from own-made products.

Costa Coffee: 760 stores

Before A coffee and a cake can amount to a third of an adult's daily calorie allowance: cherry and almond muffin has 491 calories; a full fat coffee vanilla latte hits 290 calories.

After During 2009 and 2010, gradually reduce sugar in all muffins; "monitor" caffeine levels to ensure someone having four drinks would receive below 200mg a day; replace tuna in oil with tuna in water; ensure that all foods (except croissants and butter products) are rated either yellow or green under FSA's traffic light scheme.

Pret A Manger: 180 stores

Before A Channel 4 documentary last year found 68 per cent of Pret's sandwiches earned a red light under FSA traffic light scheme; All Day Breakfast was the most unhealthy sandwich with 560 calories.

After Display calorie counts on sandwich price-tags; make gradual cuts in salt and fat; source less salty cheddar cheese; reduce salt in soups; introduce healthier breakfast baguette; increase number of half-size sandwiches.

Eat: 90 stores

Before Smoky bacon and lentil soup contains almost one-third of the FSA's 6g-a-day salt guideline. Turkey and stuffing pie has almost half a woman's 2,000 recommended daily calories.

After During 2009, will use lower-salt stock in soups; source lower-salt bread, ham and bacon; ask suppliers to cut fat; list calories per 100g online

Starbucks: 713 stores

Before Drinks with whipped cream or syrups are extremely calorific; a grande semi-skimmed hot chocolate contains 537 calories; sandwiches can be very fatty; a tuna melt panini has 482 calories. Some products are salty, such as a skinny peach and raspberry muffin with 1.3g of salt.

After Trial display of calories counts in stores; review all sandwiches and cakes against Food Standards Agency (FSA) guidelines; introduce new low-salt, low fat-products; make 10 best-selling foods healthier by September 2009.

BB's: 155 stores

Before Very high calorie count on treats. A double choc chunk muffin has 749 calories, a cheese and onion mayo wholemeal baguette 734.

After Increase number of "healthier options"; work to reduce salt, fat and sugar; review all sandwiches and launch lower salt and fat products; investigate reducing salt in bread.