What: Shares of Weight Watchers (NASDAQ:WW) jumped on Thursday after the company reported its second-quarter results. While the company's performance was mixed, better-than-expected guidance for the full year was enough to send the stock soaring, up as much as 26% at market open. By 3 p.m., the stock had settled and was up about 12% from the previous close.

So what: Weight Watchers reported quarterly revenue of $309.8 million, down 22.1% year-over-year, but slightly better than analysts were expecting. The number of subscribers continued to slump, with active subscribers declining by nearly 17% year-over-year, but the trends improved during the second quarter, according to CEO Jim Chambers. In North America, online sign-ups were positive, and the company plans to launch new initiatives later this year in an attempt to return to growth in all major markets.

The company reported non-GAAP EPS of $0.42, down more than half year-over-year, but a penny better than analysts were expecting. For the full year, Weight Watchers expects EPS between $0.57 and $0.72, an improvement over previous guidance of $0.40-$0.70, and favorable to an analyst consensus of $0.56.

Now what: While Weight Watchers soared today on the first hints of a turnaround, the stock is down about 94% since early 2012, when the company loaded up on debt in order to fund a massive share buyback at $82 per share. The stock now trades at about $5 per share.

That debt is still haunting the company. Weight Watchers paid $30.5 million in interest during the second quarter, nearly half of the company's operating profit, and any turnaround will be severely hampered by the company's balance sheet. While investors are cheering Weight Watchers' raised guidance, sending the stock soaring, the company still faces a very difficult road ahead.