Change the way you think of food. When my doctor first told me I was pre-diabetic and just a few years from diabetes in my 20's, I had a hard time wrapping my head around the fact that all the sugar I was eating was hurting me so badly. And puh-lease... I am 23 I can't possible have done much damage at this point, right?
Once he explained how hard my pancreas had to work when I ate processed sugar it freaked me out. All these things were happening inside of me that I didn't realize were going on. I then saw cakes, cookies, sodas and candy as something that would make my body go on overtime to process instead of something I selfishly NEEDED to have for my own pleasure.
Don't get me wrong, I am still tempted and give in to temptations. When I used to have sugar at every meal (and my first choice of snack) I now can control myself better knowing what happens once it leaves my tongue and enters my body.
Change the way you look at food as a way of taking care of yourself. You have just one body and by changing the way you look at food as something to sustain a healthy body for a long life, then it becomes easier to make good choices.
I also think of my body as something I have to take care of because my kids need me. And if I can't physically take care of their needs because I made bad choices related to food- I am not sure I could forgive myself for that. Plus I am the best shot and example they have for taking care of themselves inside and out.
Oh and I lost 20 lbs when I made this mental change and felt so so much better. I had no idea how all that sugar effected the way I felt and my weight.