[brachi]

I read all the answers and they're very good. I'd just add something very important: keep track of how many days you go without doing exercise, eating healthy etc. All this advice is great, but it's very easy to have a 'bad period' where you just don't realize you're going back to your old patterns. Being more specific: implement some remainder in front of you that shows your progress over time. E.g.: a piece of paper showing you the dates you exercised in green, and the ones you didn't in red. Make it your first priority to complete that piece of paper. You can go fancier with web apps or even fit-bands, but the idea is the same: track yourself everyday. And be aware of when you stop doing what you need to be doing.