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: Vitamin Shoppe (NYSE: VSI) dropped 15% in intraday trading today, despite reporting a seventh consecutive quarter of healthier-than-expected earnings.

So what: Second-quarter non-GAAP EPS of $0.41 increased 41% year over year, and beat the consensus estimate of $0.38. Investors may have been expecting more: The $0.03 beat was nothing compared to last quarter's $0.08-per-share outperformance. GAAP EPS of $0.40 rose 54%, and revenue of $216 million climbed 12% year over year.

Now what: Guidance was confusing, comparing a 52-week year to a 53-week year, and did not mention revenue or EPS. For 2011, management expects comparable-store sales growth of 7%. That suggests it will slow to 6% in the second half, from 8% in the first half of the year.

Management also plans to spend about $1 million on "additional investments to support long-term growth, primarily for the e-commerce business." That's an increase of more than 10% from its recent capital expenditure run rate. Slowing comparable store sales and management's plan to step up investments suggest that this company's growth story is aging.

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