Wall Street has been all about Weight Watchers International Inc. (WTW) - Get Report over the last year.

Weight Watchers shares has rallied 69% year-to-date and 318% in the last 12 months. Weight Watchers stock jumped 4.39% to $72.89 Wednesday morning.

It comes as little surprise, then, that the New York-based weight loss and healthy living company reported earnings that handily beat estimates. 

After the closing bell on Tuesday, the company reported adjusted fourth-quarter earnings of 37 cents, topping Wall Street's expectation of 31 cents for the quarter. Weight Watchers' earnings per fully diluted share reached 91 cents, though, due mostly to an 82-cent-per-share upside thanks to tax reform. 

For the full year, Weight Watchers earned $2.40 per share, also topping analysts' forecast of $1.65 per share. Full-year earnings gained 133% from the year before. 

Sales in the fourth quarter totaled $312.5 million, beating the analyst forecast of $309 million and growing 14% from a year earlier. For the full year, Weight Watchers snagged $1.307 billion in sales, also topping analysts' predicted $1.305 billion and up 12% from the same time last year.

Looking ahead, the company said it expects full-year 2018 revenue to approach $1.55 billion and earnings between $2.40 and $2.70 per fully diluted share.

Weight Watchers President and CEO Mindy Grossman told TheStreet that the company's impressive momentum at the end of the year was largely thanks to its new Weight Watchers Freestyle Program, launched in December.

Weight Watchers President and CEO Mindy Grossman

"That allowed us to have a very strong end to the year," Grossman said. The program, which features prominent spokeswoman and Weight Watchers partner Oprah Winfrey, allows customers a great deal of freedom in the eating and lifestyle plan.

And it appears customers took well to it. Weight Watchers subscribers grew 22.6% at the end of 2017, adding roughly 600,000 new members from the same time a year earlier.

A large part of the success of the Freestyle program has come from the digital technology Weight Watchers has pivoted to focus on. 

"We want to be a digital technology company with a human approach," Grossman said. She noted that all Weight Watchers users have an app with digital access and belong to an online community. They can supplement that digital access with meetings at physical Weight Watchers locations, tapping what Grossman called the "power and potential" of interpersonal communication face-to-face.

The company's focus on the digital experience could lead to smaller tuck-in acquisitions down the road in order to improve technology, Grossman said, but don't expect the dramatic kind of blockbuster digital/physical deal Action Alerts Plus holding Amazon.com Inc. (AMZN) - Get Report carried out in its purchase of Whole Foods Market.

A major part of Weight Watchers' digital pivot has involved smart use of social media. The company has more than 200 social media partners, including celebrities such as Oprah and musician DJ Khaled. 

"We do believe in the power of authentic social influence," Grossman said.

As for the company's most well-known partner, Oprah, Grossman wasn't interested in entertaining the idea of an "#Oprah2020" White House bid. Following a heartening speech at the Golden Globes earlier this year, Oprah became the subject of a social media movement calling on her to run for president in 2020.

"The last thing I'm going to do is opine on what Oprah will and won't do," Grossman said. But she noted that Oprah is a fantastic partner with business savvy whose opinions are taken graciously and seriously at Weight Watchers. Oprah joined the company's board in 2015 and owns a 10% stake.

Regardless of Oprah's influence, Weight Watchers has one big advantage under its belt: "The reality is and what everyone says about our business," Grossman said, "is that it works."