On March 9, 1977, the U.S. Food and Drug Administration (FDA) announced its intention to ban saccharin, an artificial sweetener in use since the turn of the century, because of studies that showed it caused bladder cancer in rats. Dieters, diabetics, and producers of low-calorie foods and beverages reacted with outrage, and understandably so. Ever since 1969, when cyclamates were banned, also for causing cancer, saccharin had been the only artificial sweetener on the market.

Opponents of the ban pointed out that the rats that had developed cancer had been fed a diet of 5 percent saccharin, or the equivalent of 800 cans of diet soda per day, a level at which many common substances would no doubt cause problems. Canada, where the incriminating studies were performed, announced its intention to ban saccharin the same day. But cyclamates were still legal in that country, combining with Cuban cigars and over-the-counter codeine to make Canada a sybarite’s paradise.

FDA officials pointed out that they had no choice. Under the law, any food additive linked with cancer had to be banned. In April, the agency backed off a bit, allowing saccharin to be sold in tablets or powder form but not in prepared foods or beverages. This was not enough to satisfy Congress, which passed an 18-month moratorium on the ban. The FDA finally settled for requiring warning labels in stores and on products containing the sweetener (this requirement was repealed by laws passed in 1996 and 2000). The congressional moratorium was repeatedly renewed, and during the 19805, as aspartame came onto the market and the Reagan administration adopted a laissez-faire approach, the saccharin ban ceased to be an issue. In July 2000, the National Institutes of Health removed saccharin from its list of suspected carcinogens.

The saccharin controversy turned out to be the high-water mark of the regulatory movement of the 1960s and 1970s. During the Eisenhower administration, the PDA’s responsibilities had been greatly expanded in an attempt to protect Americans from unwittingly consuming dangerous substances. Each success gave the regulators new momentum, and the culmination of this process, the saccharin ban, attempted to prevent willing purchasers from voluntarily consuming a product with at worst a marginal effect on health. Today, sensible regulators remember the saccharin controversy and make an effort to balance the costs and benefits of any proposed rule.