My self-sabotage comes from the fear of being wanted. (Ridiculous, I know.) I have always been the "fat" girl in the group and have always been overlooked. The few times I was given attention, I didn't know how to react to it. Relationships and intimacy scare me, and sometimes I use my weight as an excuse not to deal with those bigger emotional problems.
Recently, I've confided in my mother, who also has self-sabotage problems. It's wonderful to have someone there to stop me, and remind me why I'm dieting--for a better life, not just to attract guys. For my health, not dates.
You are NOT alone! What helps me is to recognize when I'm self-sabotaging, and to think about what I'm doing and face it. "Do I really want to buy that box of Little Debbies Swiss rolls?" "Can I really only eat one?" "Should I have the extra slice of cake?" "Are Chicken Nuggets REALLY a good idea?"
What helps me when I go to restaurants is to decided what and how much I'm going to eat before I get there. I also tell my friends/people I'm eating with not to offer my anything off there plate, or refuse me if I ask.
It's also about not putting yourself in situations where you KNOW you will end up sabotaging yourself. It's hard, but it's doable.