Why am I losing inches and not pounds when I am not exercising?

I switched to a vegan lifestyle right before Thanksgiving. I absolutely love being a vegan and it has done wonders for my health. I was getting pretty heavy. I have lost 37 pounds and quite a few inches. I haven't lost weight in a while though but my clothes just keep getting looser and looser and my measurements keep getting smaller. I'm not one for exercise except for the occasional walk around the mall :) How would I be getting smaller without exercise?