Fat replacers are nonfat substances that act like fat in a food. An ideal fat replacer would be a substance that has no health risks and tastes and looks like natural fat but has fewer calories. There is no one substance that is an ideal fat replacer, so several kinds are often used in one food.

Fat replacers are categorized into three basic types:

• Carbohydrate-based, which are made from starchy foods, such as corn, cereals, and grains; or sugar alcohols, such as sorbitol, maltitol, and mannitol. Most fat replacers today are made from carbohydrate.
• Protein-based, which are made by modifying protein, using egg white or whey from milk
• Fat-based, which are made by replacing triglycerides in vegetable oils

Fat replacers may not be listed by their brand names on the ingredient label, which makes it hard for people to identify them in the foods they buy.

If you are interested in using fat replacers, consider the following:

• Current research indicates that carbohydrate- and protein-based fat replacers don't hurt health.
• A noncaloric fat replacer, olestra, interferes with the absorption of fat-soluble substances, including the fat-soluble vitamins (A, E, D, and K) and carotenoids. Carotenoids are substances that give plants their color, and they are antioxidants in your body. Examples include carotenes and lycopene (found in tomatoes). Side effects of olestra include cramping, bloating, and loose stools.
• Although foods containing fat replacers may contain fewer calories compared to fat-containing foods, some people may have a tendency to eat more of the food containing the replacer, which makes up for the reduction in calories.

More research is needed on fat replacers. Talk with a registered dietitian if you want to incorporate fat replacers in your diet.