Trans fats may disappear from more restaurant kitchens soon. Los Angeles county officials are exploring the possibility of banning the cholesterol-raising ingredient. The Los Angeles City Council and California state legislators also are considering trans fat restrictions.

The city of Los Angeles already is studying the possibility of restricting the use of trans fats in restaurants, and legislation has been introduced in the California assembly to ban their use statewide.

The US Food and Drug Administration (FDA) requirement to list trans fat content on packaged food labels took effect in January of 2006.

Since then, pressure has been building to address the use of trans fats in restaurants, and several fast food chains, including Wendy's, Starbucks and Kentucky Fried Chicken, have voluntarily discontinued their use. A growing number of independent restaurants are also trumpeting "no trans fats" on their menus.

Trans fats result when manufacturers hydrogenate vegetable oil, a process that increases the shelf life and flavor stability of foods. Trans fat can be found in vegetable shortenings, some margarines, crackers, cookies, snack foods, and other foods made with or fried in partially hydrogenated oils.

The majority of trans fat is formed when food manufacturers turn liquid oils into solid fats like shortening and hard margarine. A small amount of trans fat is found naturally, primarily in some animal-based foods.

Trans fat raises the low-density lipoprotein (LDL), or "bad cholesterol," levels, which increases the risk of coronary heart disease, according to the FDA.

Restaurant industry officials have voiced opposition to a trans fat ban, arguing that products such as butter, cheese and any food containing saturated fats also are unhealthy but are unregulated.