The 1960s saw the beginning of the massive commercialization of dieting in the U.S. That’s when a New York housewife named Jean Nidetch began hosting friends at her home to talk about their issues with weight and dieting. Nidetch was a self-proclaimed cookie lover who had struggled for years to slim down. Her weekly meetings helped her so much–she lost 72 lb. in about a year–that she ultimately turned those living-room gatherings into a company called Weight Watchers. When it went public in 1968, she and her co-founders became millionaires overnight. Nearly half a century later, Weight Watchers remains one of the most commercially successful diet companies in the world, with 3.6 million active users and $1.2 billion in revenue in 2016.