CEO Mindy Grossman blamed this problem on the keto diet, a popular diet that makes bread and other carbohydrates taboo. During a phone conversation with analysts on Tuesday, she said that the keto was "becoming a cultural medium" and that she even called it a "surge of keto".
Wall Street is clearly nervous too.
Falling shares also hurt Winfrey, the group's second largest shareholder. She bought 6.4 million shares of WW in October 2015 – a stake valued at $ 43 million at the time. At the height of its stock value last July, its investment would have been worth about half a billion dollars, which represents a sale that she made of an action last March.
Since this July summit, WW shares have lost more than 80% of their value.
Grossman pointed out that WW will not change strategy simply because a new scheme is popular.
"Everyone in the diet is looking for the quick fix – we have already experienced this before and we know that we are the program that works," Grossman said.