Arguing the fake fat, Olestra, made thousands of consumers sick, a consumer group renewed calls Wednesday for the product to either be pulled from the market or severely curbed. Warning labels for potato chips that have Olestra say the zero-calorie fake fat can cause unpleasant gastrointestinal effects, including cramps and diarrhea, and can block absorption of certain nutrients. But the Center for Science in the Public Interest said warnings aren't enough. Citing a handful of consumers who sought emergency-room treatment for those effects, CSPI said Olestra is a "gamble with health." It also filed petitions with the Federal Trade Commission charging Olestra advertising misleads because it doesn't disclose side effects.

Olestra, sold as the brand Olean, is a synthetic chemical made of sugar and vegetable oil that passes through the body undigested. Regina McGrath of Hannastown, Penn., said she received morphine in the emergency room for severe stomach pain that lasted hours after eating 12 chips. "This was a terrible experience," she said. Harvard University's Walter Willett, a physician, said Olestra inhibits absorption of carotenoids, nutrients considered one component in preventing cancer and heart disease. Willett argued if people consume Olestra long enough, there might be thousands of illnesses from carotenoid depletion.

The FDA continues to say olestra is safe but that concerns will be publicly debated next week when its independent food advisory committee spends three days re-examining olestra, a regular procedure now that it is widely sold. The panel will look at 6,700 side-effect reports filed with the FDA, as well as Olestra's nutrient impact. The FTC had no comment. Manufacturer Procter & Gamble and Frito-Lay, which makes Olestra-laden WOW! chips, vigorously defended Olestra. Since 1996, tens of millions of people have eaten over 500 million servings of Olestra-made chips, the companies said. Only about one in 50,000 people report any complaint, and the vast majority are reporting a mild stomach upset, they said.