I'm going through the same thing myself. The problem is that it's very hard to force yourself to go out and walk around at work. The most walking I do is to the cafeteria. When I worked in NYC, I had a lot more walking to do, because I walked from Penn Station to my office, 20 minutes each way. Now I'm much too sedentary; combine that with having too much work waiting at home (renovations, children, laundry, etc.), lack of sleep (5 hours or less a night), and bad eating habits (I find myself snacking after 9 pm), I've gone from a 36 inch waist to a 40.