You've gotten some good responses already. I'm not doing any certain diet, but I have increased my protein intake, added brown rice, whole wheat pasta (in moderation), try to eat more fruit and veggies and also snack on raw nuts (not salted or roasted), mainly almonds. I try to eat fat free or low fat yogurt as a mid-morning snack and also like low-fat string cheese as a snack.
Also, when you're just standing around, watching your children do something, waiting on water to boil, watching a television show, try to do arm exercises, squats, etc. You can use up calories instead of just standing there. I'm sure with 2 boys, that's not an issue, but it's a thought! I think walking at least 30 min. a day is very good for you. Hopefully you can find an indoor track, shopping mall, community center. Good luck and let us know how you did.