I started running for 20 min before work every week day, I've been doing it for a 2 weeks now and I have lost a few lbs if that helps... I too have continued to eat the same as usual, but upped my water intake.
I generally do a few excercise classes a week, and have done for a few years, so the added excercise to my normal routine has actually made a bit of a difference. Getting up half an hour earlier has also seemingly given me more energy, and I feel more alert when I get to work.
Can't do you any harm..... as long as your hearts pumping you're burning claories.