What: Shares of weight management services specialist Weight Watchers International (NASDAQ:WW) surged as high as 20% on Tuesday after positive comments from a Wall Street analyst.

So what: Weight Watchers shares have fizzled during the past couple of weeks after their 20% Oprah-fueled pop last month, but a bullish report from ITG Investment Research today suggests that the company's partnership with the media queen is paying off where it counts most: subscriber growth. Of course, the shares have quickly slimmed down from its Tuesday highs, and are now only up about 3% at the time of this writing, giving investors plenty of frustration over yet another short-lived Oprah-centered surge. 

Now what: ITG now expects Weight Watchers to post about $260 million in sales in Q4, above the average analyst estimate of $257 million, on new membership growth of roughly 35%. "The improved trends can perhaps be partially attributed to the ownership deal with Oprah that was finalized in October," said Tomlinson. Given the company's still-heavy debt load and volatile shares, however, I'd wait for more concrete proof of Oprah's influence before jumping in. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.