Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of health and wellness products retailer GNC Holdings (NYSE: GNC) climbed 11% in early Wednesday trading after its quarterly results and guidance easily topped Wall Street expectations.

So what: GNC's first-quarter beat was so wide -- adjusted EPS of $0.60 versus the consensus of just $0.49 -- that investors have no choice but to raise their growth expectations yet again. In fact, same-store sales and online sales combined rose a solid 15.8%, reinforcing optimism over the strong health and wellness trends working in GNC's favor.

Now what: Don't expect the sales momentum to let up anytime soon. GNC now sees 2012 adjusted EPS of $2.05 per share on revenue of $2.37 billion, which is also well ahead of Wall Street's view of $1.92 and $2.31 billion. Unfortunately, with the stock busting through its 52-week high -- now up a whopping 115% over the past year -- and trading at a 30-ish P/E, it's only going to be harder for GNC to keep impressing Wall Street.

Interested in more info on GNC? Add it to your watchlist.

Fool contributor Brian Pacampara owns no position in any of the companies mentioned. Try any of our Foolish newsletter services free for 30 days.

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