Image source: Getty images.

What happened

Shares of Panera Bread (PNRA), Texas Roadhouse (TXRH 0.17%), and BJ's Restaurants (BJRI 0.38%) declined 10.3%, 11.8%, and 10.5%, respectively, last month, according to data provided by S&P Global Market Intelligence. An industry-wide slowdown is weighing on these stocks, as well as concerns that more difficulty could lie ahead for the restaurant industry as a whole.

So what

Restaurant traffic was flat in both the first and second quarters of 2016, according to The NPD Group.

"Contributing to the stalled visit growth are consumers' uncertainties about current and future economic conditions," says Bonnie Riggs, NPD Group's restaurant industry analyst. "These uncertainties have put a damper on overall consumer spending. Compounding the situation for the restaurant industry is the decline in food at home inflation while at the same time restaurant operators have been increasing menu prices." 

Restaurant chains are in a difficult position, as rising labor costs are forcing them to choose between raising prices -- and sacrificing sales -- or holding prices steady, and crimping profit margins.

This comes at a time when analysts are growing concerned that industry same-store sales growth could stall and even decline in the coming quarters, with the strong growth in previous periods likely to make it difficult to show improvement.

Now what

While these trends are somewhat worrisome, they are not specific to Panera Bread, Texas Roadhouse, or BJ's Restaurants, which have all tended to outperform their industry benchmarks over the long-term. And in times when industry-wide concerns drag down the stocks of proven market leaders, profit opportunities often arise for long-term minded investors.

We may be nearing such a situation, as this recent downturn has driven down valuations for this group significantly. As such, Foolish investors may wish to consider using this sell-off as an opportunity to pick up some shares of their favorite restaurant stocks.