The first step to lose weight without dieting is giving up the diet mentality. As I can see in the previous paragraph, diets do not work this one fact, perpetuate the mental obsession and leads to greater weight gain.
Give up diets may seem alarming, but our body and mind can be adjusted quickly, once they are free of obsessive information of diet and weight loss can begin.
The frustration of starting another diet is what causes an obsession with eating more and produces a loss of self esteem as well as the hope that you will never reach a normal weight and healthy.
Understand this, you have not failed in the diet, the diet is not working, because our bodies were not designed to live in semi-starvation mode.