WW International, formerly known as WeightWatchers, has filed for Chapter 11 bankruptcy protection on Tuesday in a bid to cut its debt after hugely popular obesity drugs upended its business model.

Shares of the company, which once boasted media mogul Oprah Winfrey as one of its top shareholders, slumped 40 per cent in extended trading on Tuesday after announcing plans to file for bankruptcy as part of a reorganization plan with a group of its lenders.

WeightWatchers began as weekly weight-loss support group meeting with 400 attendees and quickly turned into a worldwide phenomena with millions of members across the globe.

But the rising popularity of GLP-1 drugs such as Novo Nordisk's Ozempic and Wegovy and Eli Lilly's Zepbound hit demand for its traditional weight-loss programs.

Winfrey left the WW board of directors in Feb. 2024 to eliminate "any perceived conflict of interest" after she admitted to taking weight-loss drugs, the company said at the time.

About a year earlier, WW had acquired a telehealth provider to provide weight-loss drugs. But it reported a loss of $345.7 US million last year, while its subscription revenues fell 5.6 per cent year-over-year.

WW said the reorganization plan will eliminate $1.15 billion US in debt from the company's balance sheet. The company has accumulated substantial debt of around $1.6 billion US.

The company has estimated assets and liabilities in the range of $1 billion to $10 billion US, according to the Chapter 11 petition filed in Delaware bankruptcy court.

After its rebranding to WW International in 2018, the company aimed to focus on overall wellness rather than just weight loss.

The company's shares have slumped 60 per cent since the Wall Street Journal first reported in April that the company was preparing to file for bankruptcy in the coming months.