Shares of GNC Holdings (NYSE: GNC) hit a 52-week high this morning after another strong earnings report. Let's look at how it got here and whether clear skies are ahead.

How it got here
GNC has been on a steady climb higher since coming public just over a year ago, largely by consistently beating earnings estimates. This owes in part to good execution, but market trends have also helped the company. In the quarter that just ended, the company reported earnings of $0.60 per share -- $0.08 above estimates -- and a 23.4% jump in revenues.

A health kick across the country has pushed shares of health-focused companies higher in the past year, and GNC is leading the pack. The Fresh Market (Nasdaq: TFM) touched a 52-week high two weeks ago, Whole Foods (Nasdaq: WFM) has continued its solid run, and direct competitor Vitamin Shoppe (NYSE: VSI) has given investors a nice profit, too.

GNC Chart

GNC data by YCharts.

What separates GNC from these other health-focused companies is stronger margins coupled with strong revenue growth.

Company

Operating Margin

Profit Margin

Quarterly Revenue Growth

Forward P/E Ratio

GNC 14.5% 6.4% 16.9% 15.9
Vitamin Shoppe 9.1% 5.2% 19.2% 21.0
The Fresh Market 7.5% 4.6% 16.9% 31.4
Whole Foods 5.7% 3.6% 12.9% 30.5

Source: Yahoo! Finance.

Will the trend continue?
The question now is whether the trend of good earnings reports, revenue growth, and strong margins will continue. I don't see why not.

There is a general trend in the U.S. toward a healthier way of life, and supplements and vitamins are a part of that market. This trend will continue to help the company, and the stock is giving investors much bang for their buck. GNC, despite its strong growth and superior margins, is trading at a lower forward P/E ratio than that of the companies I compared above.

What's next?
Right now analysts are expecting $0.49 per share in earnings next quarter, 26% higher than last year. I don't see why the outperformance shouldn't continue, or why earnings shouldn't grow even more than that.

The Motley Fool CAPS community hasn't taken a stance one way or the other, leaving GNC with a middle-of-the-road three-star rating. But 10 out of 11 All-Stars who have rated the stock give it a thumbs-up. I tend to agree with them and think this stock has plenty of room to run higher because of its reasonable valuation and strong growth rate.

GNC is up on strong earnings, but which other companies should you keep an eye on? We've identified five stocks to watch this earnings season, so check out our free report here that highlights what to expect. It's called "5 Stocks Investors Need to Watch This Earnings Season."

Fool contributor Travis Hoium drinks GNC protein shakes, but he does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings, or follow his CAPS picks at TMFFlushDraw.

The Motley Fool owns shares of Whole Foods Market. Motley Fool newsletter services have recommended buying shares of Whole Foods Market and The Fresh Market. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.