In the first step of a renewed initiative against obesity, the U.S. government announced it would require food companies to reveal the amount of a potentially unhealthy trans fatty acids -- or trans fats -- in their products.

The new guidelines, which take effect Jan. 1, 2006, represent the first significant change in a decade o the "Nutrition Facts" label required on all processed food and beverages sold in the United States.

Trans fats, a byproduct of a process that makes oils more solid and lengthens their shelf life, are found in such foods as salad dressing, cookies, chips, margarine, vegetable shortening and crackers.

Linked to heart disease and obesity, trans fats are so harmful that the the U.S. Food and Drug Administration says it cannot establish a safe consumption "limit".

"By putting this data on food labels," said Health and Human Services Secretary Tommy G. Thompson, "we are arming American consumers with even more information to make healthy choices about the foods they eat."

"This is the beginning of a lot more rules and regulations," Thompson added.

While listing trans fat will not be officially required until 2006, the Grocery Manufactuers Association, a trade group, said it expected most of its members to start naming the ingredient immediately.

Other sources: FDA