I nominated Panera Bread (NASDAQ:PNRA) as the Worst Stock for 2009 earlier this year, unable to understand many investors' longstanding optimism. Given the stock's plummet following today's earnings release, the latest quarterly results seem to have punched a bit of a donut hole in Panera.

First-quarter net income did increase by an impressive 40%, to $17.4 million, or $0.57 per share. Net sales increased a far more modest 5%, to $320.7 million, and same-store sales increased a mere 0.7%. The unimpressive comps even included a positive bump from Easter's calendar shift; without Easter, they would have been flat.

Alas, Panera's traffic continues to wane, although price increases have helped make up for that. At company-owned stores, the comps figure included a transaction decline of 1.6%, while average check growth was 1.9%. Panera's move to boost comps by raising menu prices has been a red flag for months now, although restaurant peer Chipotle Mexican Grill (NYSE:CMG) (NYSE:CMG-B) has also taken the gamble to raise prices amid slower traffic.

Meanwhile, Panera reiterated guidance for the year, and it expects to increase earnings per share by 15% to 22%, compared to last year's 24% EPS growth. So depending on where 2009 numbers end up falling, Panera's earnings growth could slow considerably.

Panera's stock has been a popular performer for quite some time now, despite the doubts of folks like me; however, Panera bullishness may be about to hit the wall of reality. On the other hand, I've also noticed that many restaurant stocks have surged lately -- over the last three months, Cheesecake Factory (NASDAQ:CAKE) shares have fattened some 88%, Brinker International's (NYSE:EAT) shares have plumped 50%, and P.F. Chang's (NASDAQ:PFCB) are up 66%.

However, with continued high unemployment and consumers who are likely to watch their wallets for quite some time, I have to wonder whether investors' eyes are bigger than their stomachs with regard to many restaurant stocks; on this particular menu, I think it pays to be picky. As far as Panera goes, I see enough troubling signals to suspect that investors should just skip the bread.

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Chipotle Mexican Grill is a Motley Fool Rule Breakers pick and a Motley Fool Hidden Gems selection, and the Fool owns shares of it. Carve out a slice of any of our Foolish newsletters today, free for 30 days.

Alyce Lomax does not own shares of any of the companies mentioned. The Fool has a disclosure policy that eats Panera for breakfast.