The pinnacle of the all-fat-is-bad movement may have been the widely hyped introduction of the fake fat known as olestra. From a scientiﬁc standpoint, olestra is a marvel of food engineering. From a public health standpoint, olestra— sold under the misleading trade name Olean—could have been a disaster had it ever caught on.
The basic idea behind fat substitutes—that fats are intrinsically unhealthy—is fundamentally wrong. Some fats, the saturated and trans fats, are indeed unhealthy. But unsaturated fats, which make up the majority of fats we eat, actually reduce cholesterol levels and protect against heart disease and stroke. America’s fat phobia has been further fueled by the misguided notion that only dietary fat makes us fat. What really counts is total calories, regardless of food type.
An ordinary fat molecule consists of a three-carbon core (glycerol) attached to three fatty acid arms. Olestra is completely diﬀerent. Its starts out as an ordinary 12-carbon molecule of table sugar (sucrose). The sucrose is then chemically processed so it is attached to six to eight fatty acids. These fatty acids surround and protect the sucrose center.
In your mouth, olestra acts much like the fats made by plants and animals—its fatty acid arms trigger the same sensations on your taste buds. In your digestive system, though, olestra is a completely diﬀerent beast. The enzymes that break down fats are designed for the natural models. They snip oﬀ the fatty acid arms where they join the glycerol core. These small fats then pass through the intestinal wall and into the bloodstream. Olestra, though, is a foreign invader that your digestive system can’t recognize. Like a football team’s defensive line, the fatty acids in olestra crowd together and prevent the enzymes from zipping in and clipping the connection between the sucrose core and the fatty acid arms. And because the intact olestra molecule is much too large to pass through the intestinal wall, it slides unchanged through the digestive system.
This certainly sounds innocent enough. A bag of potato chips fried in olestra delivers to your bloodstream none of the fat found in a similar-size bag of chips fried in corn oil. (Keep in mind that olestra doesn’t interfere a bit with your ability to digest and store away the carbohydrates.) According to studies done by olestra’s maker, Procter & Gamble, the use of fake-fat snacks could lower the proportion of fat calories in the diet by 1 percent to 3 percent. That certainly won’t translate into long-term weight loss for several reasons. People eating chips or other snacks made with olestra might be inclined to eat more than usual—because they are fat-free! That’s often what happens to people who eat fat-free cookies. They forget that the carbohydrates in these snacks are easily turned into fat. Also, people unconsciously tend to keep their caloric intake at the same level, olestra or no olestra.
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The real problem with olestra is its eﬀect on fat-soluble vitamins and other phytochemicals. Vitamins A, D, E, and K, as well as beta-carotene, lycopene, and a host of other plant pigments and phytochemicals, can’t get into the bloodstream unless they are ferried through the intestinal wall aboard fat molecules. Olestra soaks up these fat-loving substances in the digestive system and whisks them out into the stool. This robs the body of a host of substances that play roles in preventing heart disease, cancer, dementia, and other chronic diseases. Procter & Gamble is adding vitamins A, E, and K to make up for these losses, but this won’t do anything for the other carotenoids and as-yet-unnamed substances that are important for long-term health.
Olestra’s nutrient-robbing eﬀect isn’t just theory. Eating a small one-ounce bag of chips made with olestra every day dramatically lowers carotenoid levels in the bloodstream. If this fake fat is ever used in fast-food restaurants, something for which Procter & Gamble once petitioned the FDA, or as a replacement for Crisco or other vegetable shortenings at home, it could have a major negative eﬀect on public health. Although olestra managed to slide through our FDA (with the help of intensive lobbying), it is oﬃcially banned in Canada.
Several other fake fats are also on the market. Simplesse, made by Monsanto, is protein from milk whey that’s been heated and whipped until the particles are microscopic. These tiny particles roll over the taste buds just like fat and trick them into thinking they are tasting fat. Because this airy mixture deﬂates and loses its creamy qualities when heated, it is used mostly in ice cream, sour cream, and other cool foods. It is usually listed on the food label as whey protein. A gram of Simplesse yields just over a calorie, compared with nine calories per gram of fat. Simplesse could be a nutritional plus if used in place of animal or trans fats, but its limited applications mean it probably won’t have a major impact on health.
Oatrim, a fat substitute devised by George Inglett, a chemist with the USDA’s Agriculture Research Service, is made by cooking oats, separating the soluble ﬁber, then drying the sticky slurry and grinding it into a powder. When mixed with water and whipped, it turns into a heavy, creamlike liquid that can be used in baked goods, salad dressings, sauces, and ice cream. Oatrim is rich in beta- glucans, a group of soluble ﬁbers that contribute to the cholesterol-lowering properties of oats and barley.
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Fat substitutes like olestra oﬀer health hazards rather than improvements. Those such as Oatrim, however, could be beneﬁcial if they are used in place of saturated or trans fats. Oatrim’s soluble ﬁber could further reduce cholesterol levels. An equally healthy solution is to use liquid vegetable oils in place of saturated or trans fats. The bottom line is that we don’t need new gimmicks or fake foods in order to have healthy diets. We can do this today in a way that makes eating a pleasure.