Whether it is stress, boredom, etc. it makes no difference, it is feeding something other than hunger. Each of us have to slay those imaginary dragons. Blaming it on your SD is worse yet. Not only have you found a reason to do something you know is wrong or bad for you, you are directing the blame onto someone else.
It doesn't matter if it's a SD or a blood daughter, kids bring on stress. Heck, having no kids bring on stress. You just have to control your own self and not let life dictate to you when and what to eat or how to act. If you don't, you are going to set yourself and everyone around you up for a miserable time.
You do know that there really is no such thing as gravity, right?.........The earth just sucks. ;-) Now get over it. Keep the faith.