Well, as someone who, until about five years ago, treated my body verrrrrry badly, let me tell you that the example you set for your children is, by itself, reason enough to eat well, exercise, and treat your body kindly.
My son grew up at a time when my eating was totally out of control. I'm talking sneaking food, staying up late to eat when others were asleep, stopping for chocolate malts AND French fries AND a real Pepsi after work (and before dinner), ordering two meals and two drinks then eating them BOTH. I'm not kidding when I say "out of control."
Needless to say, my son saw this and is now struggling with the same obsessive/compulsive behaviors toward food and binge-eating. Whether he would have had the same struggles had I not gone through this period, I can't say, but I do know that a good example could have made a HUGE difference in his outlook--and does now.
Fortunately, I've got my eating under control, not by dieting, which is temporary, but by learning how to eat properly, which is, I truly believe, permanent. Only now that I have control of my own life, do I feel able to help my son get his eating under control. Now that I have I lost 130 pounds and started exercising regularly, my son has followed my example by voluntarily joining a weightlifting group at school, and he has lost about 70 pounds himself. He has thanked me many times for helping him, as his quality of life just keeps getting better and better, but the only thing I could REALLY do is provide a good example. The motivation and the effort had to come from him.
So I hope you can see how important it is to provide that example for your children every day because it is important every day. Even now, if I fall off the wagon for a short time, my son goes right along with me. If I have a bad day, he has a bad day. If I choose something I shouldn't from the buffet, he does too. When I'm good, he's strong. When I'm bad, he sees it as a license to eat badly as well.
So, from someone who has been a very bad example, please believe me when I say that being a good example for your children is a VERY compelling reason to take care of yourself. Take it from someone who's been on the "other side." (And believe me, the guilt is crushing!)
Sorry for the "pep talk." I didn't know any other way to say just how important I feel this is--for you AND your children.
Shari