The breakthrough, which comes after five years of development and more than 40,000 hours of research and development, will not cause "any change in the taste or quality" or the products, Mars said.

Professor Judy Buttriss, director general of the British Nutrition Foundation, said, "Saturated fat is a health issue that needs addressing by consumers and food manufacturers alike.

"In order to reduce total intakes across the population to below 10% of total energy intake, the formulation of all sources of saturated fat -- even popular treats -- needs to be tackled.

"Any initiative to reduce the amount of saturated fat in the U.K. diet is a step in the right direction."

Fiona Dawson, managing director of Mars Chocolate U.K., said, "Our goal is to make our products better for you without compromising on taste.

"We are proud to have achieved this as a result of many years of research and investment. We remain committed to improving the nutritional quality of our products whilst delivering the same great taste to our consumers."

All five of the products will contain at least 15% less saturated fat per bar compared with their current recipes from the summer, Mars said.  

From the February 1, 2010, Prepared Foods E-dition