A lot of success is attributed to what's going on in your head. If you spend your time thinking, "This is so hard. I'm not sure if I can do it. Maybe I'll just give in and eat something," etc., then your chances of succeeding are very slim.
Thoughts create reality. It's good to have a list of "affirmations" to keep your mind headed the right direction, especially if you start feeling crummy. Here are some I will be using:
I am responsible for my own health and experiences.
I am doing this!
I am successful at whatever I set out to do.
I can get through the tough moments no matter how difficult they are.
I am healthy in mind, body, and spirit.
I am sticking with the program regardless of what else is on the calendar.
I am taking charge of my own health and my ability to make excellent choices.
I am successful!