Burger King this week unveiled what it's touting as a lower-calorie french fry.

The Miami-based chain, with more than a dozen Tucson area locations, says its Satisfries have 30 percent less fat and 20 percent fewer calories than its regular fries. The company also takes an unapologetic jab at its competitor McDonald's, saying in marketing materials that the Satisfries are 40 percent less fat and boast 30 percent fewer calories than McDonald's.

Fitness trainer and writer Malia Frey, About.com's Guide to Weight Loss guru, cautions that dieters shouldn't be lulled into thinking they are doing themselves any favors with BK's lower-calorie option.

“If you're looking for a diet-friendly alternative to french fries, Satisfries are not it.," she said in a written statement. "The fries are still high in calories and fat, and if you pair them with a high calorie Burger King burger, you could be in trouble if you're trying to lose weight.”

Satisfries are available at all Tucson Burger King locations.