06/11/2007 (The World Street Journal Online) - Trans fatty acids are created when hydrogen is added to vegetable oil – a process that makes the oil last longer. Food fried in oil containing trans fat or baked with shortening or other ingredients containing trans fat stay fresh longer. Trans fats are what gave the Oreo cookie filling its smooth, creamy texture and make French fries crisp. But trans fats have been found to raise bad cholesterol while lowering good cholesterol.

Here's a look at what's replacing trans fats:

Canola oil: This is the market name for "rapeseed oil," which comes from rapeseed plants. It is low in saturated fat (a bad fat) and high in monounsaturated fat (a good fat).

High oleic canola oil: A strain of canola oil high in oleic acid, a monounsaturated fatty acid that contributes to increased shelf life. Canola and other oils high in oleic acid resist rancidity.

Interesterified fat: Fats made through a process by which fatty acids are redistributed on a fat molecule. The goal is to produce liquid fats that behave more like solid fats, which stay fresh at room temperature longer and provide the kind of consistency found in products containing trans fat.

Products made with interesterified fat include shortening, margarine and cooking oils. Promise Buttery Spread and Enova cooking oil contain interesterified fat. Commercial oils that have undergone interesterification are also sold to food makers and used in baked goods.

Palm oil: A form of edible vegetable oil derived from the pulp of the fruit of the palm tree. It contains a high percentage of saturated fat

Palm kernel oil: This comes from the nut, or kernel, of the fruit of the palm tree. Like palm oil, it is high in saturated fat.

Saturated fat: Found mostly in beef, butter, milk, cheese and other dairy products made from whole and 2% milk. But also in such tropical oils as coconut, palm and palm kernel oils. Saturated fat, according to the American Heart Association, is considered the main dietary cause of high blood cholesterol.

Unsaturated fats: The two unsaturated fats -- polyunsaturated and monounsaturated – are considered the "good" fats. They're found in fish, nuts, seeds and some plant-derived oils. Unsaturated fats can help lower blood cholesterol level.