These are some tips that a body builder and personal trainer that I used to know told me, and they have really served me well all my life. Don't worry, it's not going to turn you into a muscleman. It's just a very sensible idea about how the body works.
When you first start exercising, you have to eat, and you have to gain weight. Do things that will make you stronger. This is increasing the muscle mass, which will require more fuel in the long run and help you to lose weight in the end. This is when body builders start bulking up. You see their body mass increasing, but you do not see the "cuts" or the muscle definition yet. Eat as healthy a meal as you can, and make sure you are getting enough protein, which will help the muscles regenerate. While you are exercising, don't worry about "eating too much." Don't eat a bunch of junk food, of course, but do not feel guilty if you hungry all the time and have to eat a good balanced meal more often than usual. Underneath all the fat, you are building muscles which will burn tons of calories.
Exchange as much process breads for whole grain as you can. Make sure you are getting your 5 fruits and veggies a day, and of course, your proteins. Basically, just a well balanced meal. Really listen to your body, because if it is hungry, it probably needs more protein to help build up the muscles you just broke down.
When you are feeling really strong, do more cardio (brisk walking, treadmill, or whatever you enjoy) than you were doing before and less weight/strength stuff. That it easy. You don't have to run like your doing a marathon or even a sprint. Just a reasonable pace is fine. This is when you will start eating less. You will probably notice your body needing to eat less, too. If you can't tell, then start paying more attention to eating regular portions. (Not regular American portions, but regular weight watcher like portions) This is when the body builders start getting the cuts, where the definition starts to show between the muscles. You have already built them up, now you are going to start burning off the fat around and in between them.
After I gained 45 lbs with my pregnancy, I lost it all within a few months. I didn't do any special diets, no surgeries, nothing. The reason is that before I got pregnant, I was in great shape. I had a good base to start off with- good muscle tone, good cardio, I was probably in the best shape of my life. As long as you can keep that muscle tone up, your body will burn off the extra calories on its own.
Good luck! HTH