Take it off. Put it on. You know what it's like to be a human yo-yo. One attempt fails. You try another. Your best friend is the bathroom scale. At what point to you recognize that what you have been doing is not the solution to your problem?
In order to change permanently you have to put yourself on a mental diet. Starve yourself of those old beliefs and thoughts. Fad diets afford only temporary change. Stats show that only 5% of people who have lost weight on a diet will remain slim. The rest return to their previous overweight condition. Why? Because the still indulge in old unhealthy thought patterns.
The most fundamental way to make permanent long-term change involves changing beliefs. When the inner mind of an individual changes, the rest of the body follows.