On Feb. 10, 2014, GNC Holdings (NYSE:GNC) is due to report earnings for the fourth quarter of its 2013 fiscal year. With shares currently trading 19% off their 52-week high, it's safe to assume that shareholders are slightly pessimistic about the company's prospects. Heading into earnings, is it possible that the nutritional supplement retailer could surprise investors and send shares soaring? Or is shareholder sentiment an accurate indicator of the company's future course?

Mr. Market sees good times ahead for GNC
Despite a downturn in GNC's share price, analysts remain optimistic about the upcoming quarter. For the quarter, Mr. Market believes the company will report revenue of $633 million. If this forecast comes to fruition, it will represent a 12% rise in sales from the $565.02 million that management reported in the fourth quarter of 2012.

In terms of profitability, Mr. Market's expectations are even higher. For the quarter, GNC is expected to report earnings per share of $0.65. In the event that the company is capable of matching analyst estimates, it will outperform the $0.50 it reported in the same quarter a year earlier by 30%. On a full-year basis, matching analyst estimates would bring the company's earnings for 2013 to $2.87, up 25% from 2012's $2.29.

How has GNC performed in the past?
Over the past three years, GNC has experienced tremendous growth. Between 2010 and 2012, the company's revenue rose 33% from $1.8 billion to $2.4 billion. According to the company's most recent annual report, the primary driver behind revenue growth was a significant increase in its comparable store sales. Throughout 2012 alone, the business saw its comparable store sales rise 11.5% in its Retail segment and 15% in its Franchise segment.

Over this timeframe, GNC's jump in sales helped contribute to its bottom line. Between 2010 and 2012, the retailer's earnings per share rose a jaw-dropping 169% from $0.85 to $2.29. In addition to benefiting from higher revenue, the company significantly reduced its costs relative to sales, especially its cost of goods sold and selling, general and administrative expenses. While GNC spent a hefty 61.7% of revenue on its cost of goods sold in 2012, this is down from the 64.8% it reported in 2012. Similarly, its selling, general, and administrative expenses declined from 23.6% of sales to 20.7%.

How does this stack up against other companies that compete with GNC, like Vitamin Shoppe (NYSE:VSI)? With a market cap of $1.3 billion, Vitamin Shoppe is much lower than GNC's $4.7 billion market cap. Given this piece of data alone, it might be reasonable to suspect that the company's growth prospects would be greater. This doesn't appear to be the case, however. Over the past three years, Vitamin Shoppe's revenue has risen 27% from $751.5 million to $950.9 million.

In addition to benefiting from an increase in its number of locations in operation and higher online sales, the business saw a rise in its comparable store sales. In 2012 alone, Vitamin Shoppe's Retail segment booked a rise in comparable store sales of 8.2%.

Just as with GNC, Vitamin Shoppe's jump in revenue helped its bottom line. Between 2010 and 2012, the company's earnings per share rose 96% from $1.03 to $2.02. The disparity between its revenue growth and net income growth was attributable to a reduction in the company's cost of goods sold and selling, general and administrative expenses. Over this timeframe, Vitamin Shoppe's cost of goods sold fell from 66.8% of sales to 65%, while its selling, general and administrative expenses declined from 25.3% of sales to 24.6%.

Foolish takeaway
Despite an apparent lack of enthusiasm from GNC's shareholders, analysts believe the company's results will be strong for the quarter and the year. Because of the significant discount the company is now trading at, combined with optimistic analyst estimates and strong historical performance, now might be a good time to consider an investment in GNC. This is especially true when you consider that the company, which is trading at 17 times 2013's estimated earnings, can be purchased at a discount to Vitamin Shoppe's 19 times earnings. As always Foolish investors should do their own research before making any investment decisions. 

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.