When you want to lose weight, give yourself a mental advantage. Use your mind to stretch yourself so you can achieve all you're capable of.
One very good method for doing this is to look for clues hidden within your defeats. Think about your most memorable past diet failure. Go over it in your mind carefully. Then ask yourself, what do I need to do differently?
Pick 5 aspects of that diet episode and address each one in a different way. Be radical, be daring. If you do it differently this time, the outcome is bound to be different.