Fat-Free Fat Carries Heavy Promises - And a Warning Label

In an age obsessed with thinness, the diet-food industry offers Americans an enduring fantasy: that no sacrifice is required in the quest for a slimmer body. As advertisers promote foods labeled low-cal, low-fat, diet, and lite, they imply that it's possible to eat like Miss Piggy and still look like Twiggy.

Yet despite all the lite products and heavy promises, there is nothing lite about the numbers registering on many bathroom scales. By one estimate, 60 million Americans are overweight, making them perfect targets for even more ''miracle'' cures.

Enter Proctor & Gamble's new zero-calorie artificial fat. Twenty-five years and a reported $200 million in the making, the product, called olestra, received approval last week from the Food and Drug Administration for use in potato chips, crackers, and tortilla chips. Instead of the 10 grams of fat and 150 calories in an ounce of regular potato chips, olestra chips will contain no fat and only 60 calories.

But fake-fat chips also carry warning labels every bit as serious as those for cigarettes and liquor. Olestra, it turns out, can cause gastrointestinal problems. It also carries away certain vitamins and nutrients - a problem Proctor & Gamble says it will address by adding vitamins.

Although an advisory committee of the Food and Drug Administration declared that olestra offers ''reasonable certainty of no harm,'' government scientists in Canada and Britain have so far refused to approve the additive. As one measure of its controversial status, the agency has been flooded with more than 700 comments from concerned scientists and physicians. And the Wellness Letter, published by the School of Public Health at the University of California at Berkeley, urges its readers not to buy snacks containing fake fat. ''Olestra is a terrible idea,'' it warns.

Even terrible ideas can be wildly profitable, of course, which is why fake fat is not the only questionable product in the dietary spotlight these days. The FDA is reportedly close to approving a controversial prescription drug for obesity called Redux. One financial analyst has predicted it could become a billion-dollar drug. But some neuroscientists say high doses could cause problems - a charge the drug's makers refute.

Eat a chip, pop a pill, and watch the scales go down. Is this what the desperate fight against flab has come to - a willingness to eat foods with adverse health effects or take potentially harmful drugs in the hope of losing weight?

The search for a magic-bullet approach to weight loss takes many forms. Women's magazines rank among the biggest offenders in sending mixed messages about food and diets. Editors often adopt a Marie Antoinette approach to food coverage - let them eat cake, preferably chocolate, and lots of it. Then, for guilt-ridden readers, they offer quick-fix diets and exercise regimens.

This month's cover stories serve as typical examples. Redbook features ''Get the Body You Want - 23 'Magic' Diet Foods.'' McCall's pairs ''No Time to Diet? Fat Blaster for Busy Lives'' with ''Decadent Chocolate Party Desserts.'' Ladies Home Journal offers ''World's Best Chocolate Cakes'' and ''Be Fit, Be Lean.''

If financial planners cavalierly assured clients that they could spend as much as they like and still get rich, the folly of their advice would be obvious. But when advertisers, diet ''experts,'' and drugmakers tell Americans they can eat what they want and still lose weight - no change in sedentary habits required - hungry listeners stand ready to believe. Please pass the fake fat and the diet capsules.

If the trend continues, will the supermarket of the future be more pharmacy than food store? Will Americans need prescriptions to buy groceries? Probably not. Still, the warning signs of a dark future on the diet horizon are unmistakable.

For now, perhaps Bert Lahr's classic TV commercial challenge to potato-chip lovers - ''Betcha can't eat just one'' - could be rephrased as a question for potential consumers of olestra chips: ''Do you really want to eat even one?''