Hi there - I read your post about your concern about your kids. I have the same worries about mine. My daughter is at the age that I started putting on this weight, and she has the same tendency to eat from boredom, always want sweets, just like the rest of us. We have a rule that she can't eat food right at bedtime, it has to be at least an hour before, and it has to be something light such as fruit or crackers. The reason for this is that her stomach will not do well if it is given a major job to do at bedtime. I used to try to analyze/direct her food choices too much at times, and she would always argue, so now I just don't. When she starts to have chocolate or sweets I ask her to think about what she had last, has she had enough "healthy food" to justify the sweet?
One day she was muching down on chips and soda and I said something to her about how if she kept eating that way she'd be big and fat like me. She said "I don't care - I know you're a good person, and its the inside that counts" I told her "Yes, but most people who see me are too disgusted to want to get to know me. You have seen how miserable I am - I'm even having surgery to change this - do you really think I'd be doing all this if being big as a house was okay?" Since then she has backed off quite a bit. It will be her own choice, and I will NOT nag her about it.
We have always had a family rule that you can have treats if you have appropriate amounts of "healthy food" for your body to use. Don't ask for a treat unless you've done that first.
This is the #1 thing I was to give her, self-awareness of her choices - food and otherwise. I always think - boy if I could go back to my teen years, I would have exercised till my legs fell off and prevented where I am today - but I can't do that, and you can't make these choices for them. You can only have open conversations, and they will have to choose to learn by your example, or the hard way.