Drive across America, and you'll see one fast-food restaurant after another:

McDonald's. Burger King. Sonic. Taco Bell. KFC. Wendy's. Hardee's. Long John Silver's. Dairy Queen. Arby's. Jack in the Box. Popeyes. Subway. Domino's Pizza. Whataburger.

There's even a chain that's aptly named "Fatburger."

Though some of these fast-food places now offer a few low-fat items, the big sales and profits are in hamburgers, French fries, milkshakes, fried chicken, and greasy pizza - the very things that the U.S. Surgeon General says are fueling America's obesity epidemic.

And instead of coming up with restaurants that offer nourishing, expertly prepared, low-fat meals, competitors to fast-food joints seem to be serving items that are even more caloric.

Take Cracker Barrel, a chain of 600 restaurants located mostly near Interstate highway exits, whose founder, Dan Evins, died last week. Cracker Barrel gained a loyal following by serving tasty - but fattening - fare such as biscuits and gravy, muffins, and country-fried steak.

Some entrepreneurs have opened restaurants serving slimming broiled fish, steamed veggies and the like. And most have gone bankrupt trying.

That's because the ingredients and technology to mass-produce nutritious food are much more costly, and it's hard to find low-paid line cooks who can quickly prepare low-fat, but yummy and interesting dishes.

And these places fail because - although most Americans say they want lower-fat meals - they won't order them when they're offered.

Some experts believe chains serving healthful fast food will evolve once costs come down or Americans get used to the idea of ordering, and paying a bit more for, a quick lentil burger and salad instead of a cheeseburger and fries on the road.

But so far, there's little evidence that such a fast-but-light food trend has started.