What is "olestra"

Olestra (also known by its brand name Olean) is a fat substitute that adds no fat, calories, or cholesterol to products. It has been used in the preparation of otherwise high-fat foods such as potato chips, thereby lowering or eliminating their fat content. The Food and Drug Administration (FDA) originally approved olestra for use as a replacement for fats and oils in prepackaged ready-to-eat snacks in 1996, concluding that such use "meets the safety standard for food additives, reasonable certainty of no harm". In the late 1990s, Olestra lost its popularity due to side effects, but products containing the ingredient can still be purchased at grocery stores in some countries.