
Addicted to diet soda? Here’s the history of its low-calorie secret weapon

Erin Blakemore/National Geographic:
Chemist Jim Schlatter had been putting in long hours at the lab. It was 1965, and the young scientist was attempting to synthesize a drug to treat ulcers. He’d been isolating various compounds along the way, and one of them had built up on the rim of a flask, getting on his bare fingertips as he worked.
At some point during his work—against lab regulations and common safety sense—Schlatter absentmindedly licked his finger to pick up a piece of paper more easily. It tasted sweet—much sweeter than sugar.
Schlatter had just discovered aspartame, an artificial sweetener that would be heralded as a breakthrough in food chemistry and weight loss. But the story of the compound isn’t all Diet Cokes and low-calorie coffees. Although the sweetener is the most popular on the market today—found in everything from ice cream to toothpaste—its future is being questioned after a recent report linking aspartame to cancer.
It wasn’t the first time that health concerns dogged aspartame.
Saccharin and the search for low-calorie sweeteners
Before aspartame, the most ubiquitous artificial sweetener was saccharin—also accidentally discovered in 1879 while German Russian chemist Constantin Fahlberg was working with coal tar. Saccharin rose to popularity worldwide during sugar shortages caused by the First World War, but by the 1960s the sweetener was being marketed to a new audience: women.
An obesity crisis was looming as the population had become more sedentary and mass marketing of food changed the way Americans ate. A parallel epidemic of fatphobia meant consumers were on the hunt for various weight loss aids—and increasingly turned to food made with artificial sweetener.
(How much of a role does genetics play in obesity?)
But not everyone loved calorie-free saccharin, which came with a bitter aftertaste, and the hunt was on for better substitutes. One contender, cyclamate, gained popularity in the diet soda industry. But the substance was banned in 1970 after claims it caused cancer in lab animals.
After Schlatter’s lab accident, he and his colleagues at pharmaceutical company G.D. Searle—then best known for developing the first commercially available birth control pill—began seeking U.S. Food and Drug Administration approval for the use of aspartame as a food additive. Aspartame held promise for as a good alternative to the popular, but now-banned cyclamate—a “super sweetener.”
“Will this restore to the nation’s figure-conscious sweet-tooths the low-calorie foods and drinks that were lost when cyclamate was banished from the supermarket?” asked one columnist in 1974. Aspartame’s supporters hoped the answer was yes.
Early questions about aspartame’s safety
After an extensive review process, the FDA in 1974 approved aspartame for use as a tabletop sweetener and for use in gum, breakfast cereals, and as an additive in certain foods like instant coffee and dairy products.
As Searle prepared to put aspartame on the market, the launch promised to be even sweeter when regulators threatened to pull saccharin based on similar concerns to those that had caused cyclamate’s downfall. As Searle stock skyrocketed, the buzz over aspartame grew.
