Understanding the workings of the mind is necessary for permanent changes in life, including lasting weight loss. If a person has a weight problem, you can bet the unconscious mind and maybe even the conscious mind have programmed the person for being overweight.
Our minds operate on two levels. There is a conscious and unconscious mind. Perhaps you've heard of the iceberg analogy. The conscious mind is smaller and above the water line. The unconscious mind is much larger and below the surface of the water. John Pateros wrote about this analogy in Process Coaching and Wholesness Work.
For lasting success, changes in the conscious mind (new habits, eating properly, exercising and thinking for successful weight loss) must be accepted and activated also in the unconscious mind.