20110421 mcdonalds frenchfries 54
French fries are displayed on a table in a McDonald's restaurant September 27, 2006 in New York City. - 

Kai Ryssdal: McDonald's shares lost about 2 percent today. Profits were up and beat expectations, but the company said food prices are going to keep on going up this year.

And here's another bad omen for fast food. We're not digging into French fries like we used to. Marketplace's Jennifer Collins reports.

Jennifer Collins: French fries have seen better days. The U.S. Potato Board says sales of frozen potatoes to restaurants are down about 6 percent. And just listen to this ad from the Idaho Potato Commission -- calling in a superhero sales rep.

Idaho Potato Commission commercial: When potato sales are less than super, our heroes arrive to save the day. It's Kent Beasley wearing tights!

Harry Balzer tracks American eating habits for the NPD Group.

Harry Balzer: Fries have lost their place within the the lunch order.

He says during the downturn, customers really bought in to the cheap a la carte menus pitched by many chains.

Balzer: One way to save money on food is just don't buy everything. Buy just the thing you go there for. The main dish is always the thing you go there for.

And the other problem is: fries have gotten a little boring, so says culinary consulant Andrew Hunter.

Andrew Hunter: I think we're seeing an evolution in how we look at fast food.

Hunter says Americans are reaching for healthier options as sides: salads, apple slices, snap peas. He says fries aren't dead; they may need to be re-imagined. Maybe that's why you're seeing sweet potato fries everywhere.

I'm Jennifer Collins for Marketplace.