If in better shape does calories burn decrease?

I am getting in better shape after exercising more.  I am worried that I may not be burning as much when I exercise as when I first started? 

I guess what I am really asking is should I still base my calorie deficit on the burn meter or increase the deficit figuring my body is starting to get used to the exercise?

As you become more fit, your body is able to complete certain tasks with less energy expenditure.  So if you continue to do the same routine it will become less challenging and burn less calories. 

The key is to continue to challenge yourself.  For example if you start out and run 2 miles in 30 minutes and you continue to run at that pace and distance as you become more fit it will become easier and burn less.  But if you run as far as you can for 30 minutes, as you get fitter you will run faster and farther and your calorie expenditure will stay the same or even increase.

But I wonder if the increased efficiency (burning fewer calories) during excercise is offset by the increased metabolism that allows you to burn more calories while resting?  This may be wishful thinking on my part, since it already seems hard on very overweight people that as they succeed (lose weight) they need to reduce their intake to offset the fact that they are moving a smaller mass around on a daily basis.  Or, as I am doing, leaving my intake the same and accepting a slower loss per week.

It's not completely offset, but it does help.  Your basil metabolism will go up because lean tissue uses more energy than fat tissue. 

The main reason you are not burning as much from exercise is that you are not dragging around the extra weight.  Either increase the intensity and/or length of your workout, or wear a back pack. :)

What crgrier said.