Fats are an important source of energy for the body. They supply essential fatty acids that are needed for growth and regulation of many of the body processes (such as controlling inflammation and clotting of blood). These fatty acids can't be made by the body and must be comsumed in our diet. Fats are also needed to help the body absorb the fat-soluble vitamins, A, D, E and K.

Fats are divided into two main categories: saturated and unsaturated. Saturated fats tend to come from animal products and some plant products. Examples of sources include: whole milk, butter, lard and fat from beef, lamb, pork and poultry. Plant sources of saturated fat include coconut oil, palm oil, palm kernel oil and cocoa butter. These fats are commonly called the "bad" fats because they raise levels of total cholesterol and LDL cholesterol, factors associated with an increased risk for coronary artery disease.

Unsaturated fats can be broken down in to monounsaturated and polyunsaturated fats. Examples of monounsaturated fats are olive oil, canola oil, peanut oil, cashews, almonds and avocados. Some polyunsaturated fats are corn oil, soybean oil, sunflower oil, cottonseed oil, fish and shellfish. When used as a replacement for saturated fats, unsaturated fats are considered to be "good" fats because they help lower cholesterol levels and the risk for heart disease.

Trans Fats

There's another type of unsaturated fat, called trans-fat. A small amount of trans-fat is present in some animal-based foods. But most of the trans-fat in our diet is man-made. Trans-fats can be produced when hydrogen is added to heated vegetable oils (a process called hydrogenation). The processing produces a fat that maintains a longer flavor and shelf-life. Many packaged foods, like cookies, crackers, snack foods, baked goods and salad dressings contain varying amounts of trans-fats. Shortening and hard margarine are also common examples of foods produced through hydrogenation.

Trans-fats are another type of "bad" fat. Not only do they raise LDL cholesterol levels, they also lower the HDL, or good, cholesterol levels as well. Trans-fats also increase the levels of triglycerides.

The Fall of Trans-Fats

No one knows exactly how much trans-fat is safe to eat. But since this fat is associated with an increased risk for heart disease, the American Heart Association recommends limiting trans-fats to less than one percent of total energy consumption.

In January 2006, the FDA required food manufacturers to list the trans-fat content on package labels. But Megan Anderson, R.D., a Registered Dietitian with the Heart Hospital of Austin, says the Nutrition Facts panel can be deceiving. A product containing less than 0.5 grams of trans-fat per serving doesn't have to have the trans-fat listing on the panel. That means consumers must learn to read the ingredients label for clues. She recommends looking for words, like "hydrogenated" or "partially hydrogenated," in the ingredients list.

In December, 2006, New York City became the first city in the U.S. to ban the use of trans-fats in restaurants. Food establishments will be required to eliminate most frying oils with trans-fats by July of this year and from all other foods by July 2008. Some fast food restaurant chains have jumped on the trans-fat ban and other cities are considering their own ban.

Anderson says while the dust settles on trans-fats, consumers should still keep a heart-healthy attitude. Trans-fats can be replaced by more healthy fats and oils, but people still need to keep an eye on their total fat intake. So even if trans-fats fall by the wayside, consumers will still need to read product labels.

For information on trans-fats:

FDA, Center for Food Safety and Applied Nutrition

International Food Information Council