Weekends are always really tough for me as well. And once I am in a bad pattern, it can be very hard to break it. Sometimes I find an over-correction can be helpful to break the bad habits that have taken hold and "reset".
By over-correction I mean, maybe you tell yourself that for the next two weekends (or whatever time period you like) you will NOT go out to eat. And then after that you can resume your going out as long as you make reasonable choices. So you aren't saying NEVER to eating out, you are just building in a chance to get back in your groove and see if you can then be more moderate in your choices after that which would establish a better pattern.
Just one idea.