Try making one decision at a time.
For one week, cut out all other drinks but water. No soda or alcohol or anything. The next week, cut out all fast food - and replace it with fruit. The next, candy. And so on.
It will take awhile, but eventually you will get to where you want to be. You have to be confident in yourself. This is YOUR life. Don't let food run it. Take control and make those baby steps.
You can do this. Keep your head up
