There is a reason you acquired your negative habits. Something started you down the unhealthy path. It might be something you cannot change. Still, you must figure out what it is and change the way you deal with it. If you cannot determine your reason, than sit down and take the time to look at your life in detail. Look back and figure out when you started your negative behavior and look at what happened in your life at that time or just before that time that could have possibly triggered it.
Example 1. Maybe your negative behaviors began before you learned to walk. Children tend to follow what their guardians do, as opposed to what their guardians say. If your guardian was overweight, your natural tendency would be to become overweight. You would eat the kind of foods your guardian ate. You had no control over your diet when you were too young to prepare your own food. You may have been bribed with sweets as a child. You may have been fed foods high in sugars and fats. This would make it likely for you to develop eating behaviors that would lead to weight gain. If you crave sweets or high calorie prepared foods, it may be someone else's fault. The good news is, now you can prepare your own food. Now you have a say in what you eat. Cravings may be strong but your mind has the power to be stronger. Recognize that you are now in control of your own diet. Over time cravings for junk food can be replaced by cravings for healthy food after you feel the positive effects that a healthy diet can offer.
Example 2. Maybe someone badgered you until you developed a fear of gaining weight. This started you on a pattern of unhealthy repetitive crash dieting that resulted in weight gain. You need to rid yourself of this fear. You need to stop dwelling on your weight and start loving yourself for who you are inside. Stand up and say, "you've had it!" and decide that from this moment on, you're not going to let some fear, instilled by someone else, control your life. From now on you are going to use your intelligence. Accept that you are overweight and that it will take time to reach a healthier weight. Take control and start treating your body to a normal healthy diet, no more fasting, no more pills, three beautiful square meals a day, and some fun physical activities. Accept that you may slip a couple times. But stay on the path to health.
Example 3. You were abused sexually. To protect yourself you gained weight. Maybe you subconsciously felt that you were less likely to be abused sexually if you were over weight. Maybe eating was one of the few things you still felt in control of. Maybe along with the weight gain, you have difficulty achieving an intimate relationship for fear of being hurt again. Stand up. Recognize your problem as the fear it is. Decide that you and your life will no longer be controlled by this fear. Recognize all the costs now and down the road to remaining under the control of this fear and tell yourself "I've had it! It's my turn! It's my time! I will no longer be a slave to this fear. I will no longer sacrifice my health and quality of life because of something that happened in the past. I will no longer hurt myself and will no longer fool myself into believing that being overweight keeps me safe, because it doesn't. Being overweight is the most immediate danger to my health and to my life. Improving my health and self-image is crucial to my happiness. Life is too short and there is too much love to share. Take steps to reach out to positive people and focus on the joy it brings. Seek professional help if you need to. Once you recognize that you gained weight for protection, and that the protection you gained does not work and in fact is hurting you, then you will be empowered to lose weight for your own benefit. Once you recognize that you shut out the world in order to protect yourself and that this behavior leaves you alone with no support or help from others to take on life's challenges, you will be empowered to change.