Our most discussed stock last week by far was Herbalife (NYSE:HLF), which gapped down sharply this week after its first-quarter earnings announcement.

Herbalife announced record operating results for the first quarter. Compared with the same quarter last year, earnings jumped 24% to $108.2 million, or 88 cents per share. This topped the 81 cents per share consensus earnings estimate by 9%.

Over the same period, net sales climbed 21% to $964.2 million. In North America, the company’s sales advanced 26%, in South and Central America they jumped 32% and in Asia Pacific they rose 30%.

Buoyed by strong sales growth across all six regions, management has raised its 2012 earnings guidance. For the rest of the year, the company sees earnings in the range of $3.58 to $3.74 per share; this tops the Street view of $3.65 per share.

In addition, the board approved a quarterly payment of 30 cents per share. Shareholders of record on May 15 will receive this payment on May 30. Currently, Herbalife’s annual dividend yield is 1.7%, which is the highest in the Drug-Related Products industry.

Nonetheless, shares of Herbalife dropped. Driving this sell-off was hedge-fund manager David Einhorn, who questioned the company about a minor detail in its financials during its conference call.

From what I see, Einhorn was just trying to manipulate the stock for a quick short sale, and while he got his wish in the short term, this does not impact my long-term outlook for HLF.

This company is profiting from the U.S.’s obsession with weight loss and healthy living, and it still has plenty of room to grow.  You simply can’t keep a good company like this down for long.

Although many investors got caught up in the panic sell, the fact remains that one short-seller’s comments don’t change this company’s prospects. I expect the stock to bounce back as other investors realize this, so I reiterate my buy recommendation.