carbmaster bread

I'm a huge fan of the carbmaster bread that I get at my local kroger; it is advertised as having 30 calories per slice and is super filling! I'm worried I've been duped about the caloric content though. The nutritional information is below Fat: 1g Carbs: 9g Protein: 4g Fiber:5g ​ From the fat, carbs, and protein, there ought to be 61 calories per slice. Does the fiber cut the number of calories in half? How does this work? All I want to make sure of is that I'm not eating bread that actually has twice the amount of calories I think it does.