It seems as if Steak 'n Shake (NYSE:SNS) can teach hip-hop singer Kelis a thing or two about using milkshakes to bring the boys to the yard. On the strength of its holiday shakes -- which this year included a white chocolate concoction along with its traditional eggnog offering -- the value-minded table service chain recorded double-digit gains on both ends of the income statement in its fiscal first quarter.

Sales came in 11% higher while earnings rose 12% to $0.18 a share. With same-store sales up a snappy 8%, the company recorded its eighth consecutive quarter of higher comps.

It doesn't seem right, does it? After all, over those same two years you've seen burger chains like McDonald's (NYSE:MCD) and Wendy's (NYSE:WEN) move away from promoting their unhealthier grub in favor of premium salads and fruit slice sides. So why is Steak 'n Shake getting away with murder by serving up fatty fries, heart-pounding steakburgers, and caloric ice-cream shakes?

Maybe that's the answer right there. Folks still like to cave in to their decadent indulgences, and the "healthier than thou" approach of the leading burger chains may be sending folks back to the Steak 'n Shakes of the world, as well as the fast-food chains that flaunt their beefy burgers, like Checkers (NASDAQ:CHKR) and CKE Restaurants' (NYSE:CKR) Hardee's.

With 429 restaurants and counting, the company expects more moderate growth over the balance of fiscal 2005. It is still looking to earn between $1.08 and $1.11 a share this year -- a gradual improvement over fiscal 2004's $1.00 showing (which, in turn, was a step up from the $0.90 it earned a year earlier before restructuring charges that helped spark the comps turnaround).

Consistency is always good in the restaurant chain business, but it can be even better for conservative investors who can sleep well at night owning shares in a company that has decades of operating history and seems to be inching ahead with every passing quarter.

Kelis? Watch if you're smart.

Find yourself eyeing the Steak 'n Shake salads over the steakburgers and milkshakes? What about low-carb diets to get in shape for swimsuit season? All this and more -- in the Fools Fighting Fat discussion board. Only on

Longtime Fool contributor Rick Munarriz needs to drive a dozen miles to get his steakburger -- but he'll do it gladly. He does not own shares in any companies mentioned in this story. He is a member of the Rule Breakers analytical team, seeking out tomorrow's great growth stocks a day early.