Fast food restaurants went on a bacon binge a few years back, adding a little salt and–in theory–a little crunch to burgers and chicken sandwiches. Except that the fast food bacon was rarely as crispy as it looked in the ads, which meant that most of the new sandwiches with bacon were plagued with "chew ratio" problems.

For those who aren't familiar with a term that I made up, the "chew ratio" (or C.R.) refers to the amount of time it takes to chew the various elements in a given sandwich or entrée. If the bacon on a burger is too chewy, you may find yourself still gnawing away at it long after the bun, burger and veggies have been reduced to a nauseating pulp in your mouth. And as any fast food junkie will tell you, the less time that food spends near your tongue, the better.

Where I live, Hardee's–which some of you know as Carl's Jr.–has come up with a substitute for bacon in the meat-on-meat sandwich sweepstakes. The Philly Cheese Steak Burger tops a regular hamburger with sliced flank steak, creamy cheese and grilled onions, recreating the overall peppery, savory flavor of a cheese steak sandwich. Experience-wise, the Philly Cheese Steak Burger does what it's supposed to, right down to that unique sensation of "instant heartburn" familiar to cheese steak aficionados.

But steak and roast beef tend to be the iffiest ingredients for sandwiches, because their C.R. varies so wildly. Many's the time I've taken a bite of a deli roast beef sandwich and had my teeth sink smoothly through the bread, only to come a cropper when they reach the meat. That's more or less what happened with the Philly Cheese Steak Burger too. No matter how hard I bit down, the steak chunks refused to cooperate with my mastication plans, and were frequently pulled right out of the sandwich and left to dangle greasily against my chin.

Arby's new Roast Beef Gyro has pretty much the opposite problem. The one thing that Arby's has always had going for it is that their roast beef is sliced so thin that it almost dissipates on contact with the mouth. And as odd as it feels to call Arby's roast beef piled inside of pita bread a "gyro," the alien texture of Arby's meat is just strange enough to approximate that weird lamb/beef tube that provides the filling for most "real" gyros. The Arby's Roast Beef Gyro gets the flavors down fairly well too, with a nice cucumber-y sauce carrying the load.

But the roast beef is so tender that the pita cocks up the C.R. My teeth worked so hard to get through the outer wall of bread that by the time I penetrated the core, a lot of the meet had been squozen out the top, accompanied by cucumber sauce and onion. And the beef that did make it into my mouth dissolved almost instantly, leaving me to grind through the dense, now-soggy pita.

So I'm done with fancy new fast food sandwiches for now. (Sorry, Burger King Extreme Spicy Tendercrisp Chicken Sandwich!) Time to look for some new kind of chip, candy bar or soda to consume. Something easier on the old choppers.