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 restaurant operator Ruby Tuesday (NYSE: RT) appear to have gotten severe food poisoning from a serving of company earnings yesterday. The stock groaned its way down as much as 17% in intraday trading today.

So what: Results for the company's fiscal fourth quarter were u-g-l-y, and it didn't have ... OK, so it did have an alibi, but it wasn't particularly convincing. Management said that severe winter weather affected its results more than competitors because of Ruby Tuesday's concentration on the Eastern part of the country. In addition, new investments hurt the bottom line. What investments, you ask? A prime one cited was the company's new "fresh bread program." So, perhaps we can blame it on the grain. (Rimshot!)

Earnings per share for the quarter -- excluding accounting gains and losses -- were $0.24, versus $0.28 last year and analyst estimates of $0.31.

Now what: The view ahead wasn't any more encouraging than the view looking back. At the top end of the guidance range, the company sees same-store sales growing 1% for the full year, and it expects that margins will remain flat. (There's that darn bread again!) Management provided an EPS range of $0.74 to $0.82, which trails the $0.90 that Wall Street expected.

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Fool contributor Matt Koppenheffer does not have a financial interest in any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.