Olestra

1996-1999

»100% Satisfaction, 0% Guilt.« These fat-free chips contain the controversial additive Olestra. During the low-calorie craze of the 1990s, several kinds of low-calorie chips were launched. What could be better than chips without any calories? Olestra was approved as an additive in 1996, but it quickly lost its popularity due to unpleasant side effects. The body could not absorb the substance, which in larger amounts caused gastric cramps and diarrhea. Olestra and the chips became known for causing »anal leakage.« 

Additional info:

Wikipedia - a decent article about this infamous substance

Fastcompany - The Chips That Sent Us Running To The Loo

Pringles Fat Free Chips Commercial from 1998: