IN THE BAG: An “exceptional experience” can shed pounds.

Full-service operators can learn plenty from sandwich king Subway. The chain figured out years ago that touting its menu offerings as part of an effective weight-loss regimen can drive growth. Annual sales have skyrocketed since commercials starring diet guinea pig Jared Fogle first appeared in 2000.

What's surprising is how few other restaurants have adopted a similar tactic since. That's about to change, as another QSR chain has moved to position itself as a place that is part of the solution to the obesity crisis, not part of the problem.

Late last December, 5,500-unit Taco Bell rolled out the Drive-Thru Diet. Its promise is that patrons who make “sensible choices,” including lots of Taco Bell food drawn from the seven-item “Fresco” portion of the menu, can lose significant weight.

The Jared-equivalent ad spokesperson is Christine Dougherty, who reports a 54-pound weight loss after following this strategy. So the Drive-Thru Diet works, right? Well, sort of. Here's the lengthy disclaimer Taco Bell puts on the diet's dedicated website:

“Exceptional experience based on an average intake of 1,250 calories a day, with average daily reduction of 500 calories over two years with sensible food choices. For a healthier lifestyle, pay attention to total calorie and fat intake and regular exercise.

“Drive-Thru Diet' is not a weight loss program. Fresco can help with calorie reductions of 20 to 100 calories per item compared to corresponding products on our regular menu. Not a low calorie food.”

Oh. Yet Taco Bell has now cast itself as a good place to go for people who want to eat healthfully. It's the right message, given the gathering power of nutritional advocates. Full-service operators, here's your opening.