Fueled by climbing demand of its meetings and online services, Weight Watchers (WTW) surged nearly 34% to an all-time high on Thursday upon reporting a much stronger-than-expected fourth-quarter profit, leading the company to reveal an outlook widely ahead of Wall Street estimates.

The New York-based company posted net income of $48.9 million, or 66 cents a share, up 161% from $18.7 million, or 24 cents, in the same quarter last year. Excluding certain one-time items, the company earned 64 cents a share, ahead of average analyst estimates polled by Thomson Reuters of 56 cents.

“We are seeing terrific enrollment volumes in our North American and U.K. meeting businesses and further strengthening in our WeightWatchers.com business,” said David Kirchhoff, the company’s chief executive.

Revenue for the provider of weight management services was $356.7 million, up 15.6% from $311 million a year ago, trumping the Street’s view of $321 million.

Stronger demand for meetings in North America helped lift sales, with meeting revenues in the region up 15.1% year-over-year, driven by a 6.8% increase in attendance. Internet revenues climbed 31.1%, helped by a 38.2% improvement in active online subscribers.

Looking ahead, the company sees 2011 earnings in the range of $3.50 to $3.85 a share, ahead of Wall Street’s view of $2.77 a share.

Follow Jennifer Booton on Twitter at @Jbooton