What in the world are you eating?

It seems that many of us don't really know what's in our food, or how it affects us. Anxious to drop a few pounds or lower our cholesterol after those holiday binges, we turn to reduced-fat snacks. But, as Debra Miller points out, just because a food is labeled "low-fat," it's not necessarily going to help you lose weight. "Fat-free cookies can have as many calories as regular cookies," she says.

Nearly everyone is concerned about fat these days: food companies are eager to cash in on the lucrative snack market, nutritionists want to reduce Americans' dietary fat intake, and consumers hunger for tasty treats that won't lead to larger waist sizes. So, as the corporations and chemists cook up new ways to fake fats, and the consumers, well, consume, the FDA and nutrition researchers like Miller are trying to understand how effective fat-reduced products are in lowering overall caloric intake.

Miller, a graduate student at Penn State, studies a common, fatty, savory culprit, the potato chip. She fed 48 males and 48 females potato chips at a snacking session every weekday for two weeks, followed by a week off and then two more five-day weeks of "chipping." She recorded their caloric intakes and checked how their eating habits differed when they were given nutrition information and when they weren't. And, most importantly, she used a completely new, fat-free chip fried in olestra, a fat substitute, for half of the study. "These chips taste exactly like the full-fat chips," says Miller. "No subjects (who were not given nutrition information) could tell them from the real McCoy."

You may remember the big stir over Simple Pleasures brand ice cream a few years back, which used a fat substitute called Simplesse. Simplesse, made from egg proteins pulverized into particles smaller than the tongue can detect, makes food seem creamy. Since creaminess (texture) is one of fat's major contributions to food, creating texture is the basis of most fat-substitution strategies. Margarine spreads, for example, use proteins and carbohydrates to trap water in a gel, providing a creamy feel. But olestra, a sucrose polyester that Procter & Gamble has been developing and modifying for the last 15 years, does not just mimic the qualities of a fat, it really is a fat, and behaves like one.

A sucrose polyester (SPE) is not used to make sugar leisure suits or edible underwear. The SPE, made from sucrose and long-chain fatty acids that have been esterified (combined with alcohol to produce the ester and water), is a bulky molecule, not digestible by the human body (the pancreas can't break it down), that passes through the digestive tract unchanged, much like a fiber would. But, in all other matters, it behaves like regular fats olestra is heat-stable (unlike other substitutes) and can be used to fry foods (unlike other substitutes). "Meat fats are the only things we can't replace with olestra, except maybe in processed meats. I don't know much about processed meats," says Miller. "But then again," she adds, laughing, "I don't think I want to."

Toxicology research has already confirmed that SPE is safe for human consumption, but since the impact of olestra on the consumer market could be great, the FDA is also requiring extensive testing on the possible health benefits of eating olestra-cooked foods. Hence the necessity of Miller's study, to see whether or not olestra reduces caloric intake.

Miller divided the participants in her study into categories based on sex, weight status (lean or obese), and restraint ("Restraint refers to how concerned people are with body weight and food intake whether they watch their weight, or are less concerned about eating.").

The men, she found, were relatively stable snackers, showing little difference in their eating habits regardless of chip type or weight class. And, they generally ate twice as much as the female subjects something of a surprise, based on the women's interviews and questionnaires. "Most of the women listed snacks, and especially potato chips, as a problem," Miller says, shrugging, "but. . ." Though the females didn't match up in terms of sheer chip volume, their statements prove valid when examining the difference between quantity of olestra chips consumed versus quantity of fatty chips consumed. Obese or restrained women who were told their chips were fat-free ate significantly more olestra chips than regular ones, no doubt believing the reduced fat gave them more license.

Among subjects who weren't given the fat information, restrained women ate less than the unrestrained women (regardless of chip type), as expected. But a curious thing happened with the obese women. With no conscious idea as to which type of chip they were eating, these subjects actually ate more of the fatty chips than the olestra chips. Miller has no ready explanation, but speculates that the obese women's bodies may have some ability to rapidly judge fat intake, so that, when it's available, they eat more fat. It's not the taste, she's sure she's eaten hundreds of the chips herself. "After a long time, if you really concentrate," she confides, "you start to notice a slight waxiness, but that's about it."

Miller still has to examine the eating habits of the subjects outside the laboratory (as recorded by each of them during one 24-hour period every week of the study), as well as check for any correlations between chip consumption and the menstrual cycle, but the word on olestra now is, "Basically, we think it's good," says Miller. Even allowing for the overeating of the olestra chips by the informed eaters, the subjects still reduced both their fat and calorie intake when eating the olestra chips than when eating their fatty counterparts.

But for weight control, Miller reminds, we savory-snack-seeking

Americans still need to keep a cap on overall energy intake. "Olestra's a substitute for fat," she says, "but not for common sense."

Debra Miller is a graduate student in the College of Health and Human Development pursuing a Ph.D. in biobehavioral health and a minor in nutrition, 105 Benedict House, University Park, PA 16802; 814-863-8573. Her adviser, Barbara J. Rolls, is professor of nutrition in the College of Health and Human Development, 104 Benedict House, University Park, PA 16802; 814-863-8572 This project was funded by the National Institute of Diabetes, Digestive and Kidney Disorders.