Obesity can result from an adaptation to one's preferred foods. It is not the foods themselves which "cause" or "cure" obesity. It is possible for a person to become overweight eating low carb or all fruit (and they have). Persons can also remain lean eating so-called "junk" or "processed" foods (there are numerous examples of that, as well). So how does one lose weight?
Weight loss can only happen between meals. The longer one goes between meals, the more weight they will lose. But an obstacle arises when one becomes preoccupied with eating. The solution is to become preoccupied with losing weight or finding something else to occupy your time more effectively away from food or eating.
Too much preoccupation with losing weight can result in anorexia. Preoccupation due to depression or other extreme emotions can also lead to losing weight. What confuses people is that extreme emotional periods can also lead to obesity when one is trying to constantly take a break from a burdensome emotional state. Finding a preoccupation that enables weight loss is not as hard as it sounds. It's just a matter of keeping yourself busy in a way that effectively avoids focusing on hunger or eating.
Harnessing preoccupation is the cure for obesity.