Each Burger King has its own pricing, but we have found that most of them offer a single cheeseburger, a double cheeseburger, and a triple cheeseburger. Normally the triple is often up to 50% less expensive than buying 3 cheeseburgers! Since we're going to throw away the bread anyway, it's really QUITE a deal.
They also have a grilled chicken. I often see it served with a caesar dressing, but simply ask them not to put that on the chicken.
Get an iced tea with it, and you've got the perfect low carb meal!
UPDATE: Burger King has begun to offer bunless burgers as a normal menu item, and even offers a low carb meal plan!
Burger King Offers Bunless Burgers
Restaurant Reviews for Low Carb Dieters
Tips for Eating Out on an Atkins Diet
500 Low Carb Recipes
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