What happened

Weight Watchers International, Inc. (WW 2.25%) investors were celebrating again Friday after the weight-loss specialist posted another blowout earnings report.

As a result, the stock was up 24.9% as of 11:53 a.m. EDT.

A man making notes in a notebook with dishes of healthy foods around the table.

Image source: Getty Images.

So what

The company lifted its full-year guidance for the second quarter in a row after showing off strong subscriber growth. Total subscribers increased 20% to 3.5 million from a year ago, and paid weeks were up 17%.

That drove revenue up 10%, or 12% in constant currency, to $341.7 million, which topped estimates at $334 million. Operating income increased 31% to $96 million, and earnings per share jumped from $0.46 to $0.67, which blew past expectations at $0.51.

CEO Mindy Grossman, who took the helm last month, said Weight Watchers' "strong performance is due to the broad-based improvements the company has implemented, including updating the program, enhancing the digital offering, and refreshing the meetings experience."

Now what

The strong momentum prompted the company to raise its guidance again as it's now calling for earnings per share of $1.57 to $1.67, up from a previous range of a $1.40 to $1.50, and well above estimates at $1.29.

The stock is now up an incredible 262% this year. While it should eventually cool off, the near term looks bright as long as subscriber growth remains strong and analysts keep underestimating the company.