Your body and mind always has a default decision. For people with a full time job how is it that you always seem to make it to work when you are supposed to. The default response is to get up and go to work. You have already made the decision and commitment that you are going to the work. Then when the time comes you get up and drive to work. What if you did this with your health?
What if you already decide and commit to be healthy? Then when the time comes you will wake up early and go to the gym. When you go out to eat, you will order the salad or grilled chicken instead of fried food.
What if you already decide and commit to be happy? When the time comes you will do whatever it takes to bring happiness in your life.
Make the decision easy and make your default answer the one that is best for you.