'The fact that this is perennially among the most popular resolutions suggests just how difficult it is to commit to. But you can succeed if you don’t expect overnight success. "You want results yesterday, and desperation mode kicks in," says Pam Peeke, MD, author of Body for Life for Women. "Beware of the valley of quickie cures."
Also, plan for bumps in the road. Use a food journal to keep track of what you eat and have a support system in place. "Around week four to six.