One thing I learned after being successful at Weight Watchers is that keeping track of what you are actually putting in your mouth. It's so easy to forget that peice of candy that you grabbed at work, or the bag of chips that came with your sandwich. Journaling helps keep you honest, and allows you to see what is really going on with your eating habits. You can track your progress, to understand why some weeks you were successful and other weeks not so much, by looking back at your journal.
This is a simple to use journal that will fit just about any eating program you are using. Each day allows you to enter your food consumed, activities (i.e. exercise), water... as well as a place to enter your thoughts and I feelings. You get a graph to chart your progress, a small journal to use while traveling, and a list of many foods in the back with their basic nutritional information. The book also contains a great deal of practical advice that many can find helpful.
This book will not solve your weight issues, and it doesn't promise a magic bullet that will keep you thin forever. What it will do is give you an extremely useful tool that will help keep you on your program and allow you to accurately track your progress.