You don't need to eat more on the specific days that you exercise (personally I'm always hungrier the day after doing something more intense than usual), but if you are exercising, you should be eating a little bit more overall than if you were completely sedentary. The major thing is simply to create a deficit of 500-1000 calories a day and to keep it up for as long as it takes. It's hypothetically possible that by eating more on exercise days you're going over the amount you'd need to eat to lose noticeable weight so soon, but it's not very likely. I'd give it at least a few more weeks before changing anything. Odds are that by then you'll be seeing some more loss and will have forgotten what you were ever worried about. (And more importantly, you won't have driven yourself nuts chasing ghosts in the meantime! :) )
As has been mentioned, there's tons of reasons for the scale not to behave as we expect it should. Let's say you are keeping to your goals very well and are therefore losing a consistent 1 pound of fat every single week. The scale might show anything from a loss of four pounds to a gain of a couple -- purely from water. There's not a whole lot you can do about this. Being consistent with your hydration, keeping sodium down, weighing first thing in the morning all the time -- that can help, but it won't prevent the scale from doing weird things. You can't control what your hormones do (or when they do it), you can't control the retention of water in stressed muscles (or how much is retained, or how long it lasts), and so on. It just happens.
It's important, therefore, to stay focused on what's really vital, and that is what you are doing, day to day. If you have what you believe is a good and sustainable plan, keep it, and don't let the scale tell you it's not working unless a good month has gone by, because probably it is working.
Height 5'8 1/2"
GW: Originally 150. Maintaining at about 146 since June 2013.
5K 4/21/11: 31:55
|41 Maintenance Weeks