Synthesized substances created to replace fat in a variety of foods. To date, the Food and Drug Administration (FDA) has only approved two of these substitutes — Simplesse and Leanesse. Simplesse, manufactured by NutraSweet, is composed of milk protein and egg whites. This all-natural fat substitute is very low in calories and cholesterol free. It's used in a variety of foods including frozen dairy products, yogurt, cheese spreads and salad dressings. Leanesse, a ConAgra product, is made from oat flour (Oatrim) through a heating-and-cooling process that produces a flavorless gel that imitates the texture of fat. It's used in foods such as frozen dinners and energy bars. Yet to receive FDA approval is the much-touted Procter & Gamble product, Olestra. This no-calorie, sucrose-polyester fat substitute is a composition of sugar and fatty acids, embodied in a molecule so large that it moves right through the human system without a trace. Olestra contributes the same cooking benefits (such as crispy French fries) and flavor as fat, but without the associated risks. Although it was discovered in 1968 and has a decade-old petition filed with the FDA for use (in shortening, oils and snacks), Procter & Gamble still awaits approval for this landmark food additive that could change the way America eats (or certainly the way it gains weight). See also fats and oils.