It’s true what most people say; it's mind over matter.  Sometimes we can be so use to doing certain things or eating a certain way that our mind convinces us that it is the right thing to do. The first and most important step is to convince yourself that you don’t need these things. Instead of grabbing a muffin or a snicker bar, grab yourself a piece of fruit or a handful of nuts.  Remind yourself of the benefits of eating healthy in the long run.  Think about how long you have to work out after eating junk food.  Is it worth it? Do you really want to spend an hour at the gym burning off a doughnut or a snicker bar?  Also, eat more protein. It moves through your GI slower and you will feel less inclined to eat more. Start making your own healthy snacks, soy jerky, carrot sticks without a dressing, fruit, celery sticks with peanut butter, hummus with wheat crackers, and nuts are all good to eat.  Do treat yourself, just only a little. Never grab the whole bag, set out a portion and eat that only.