Weight regain is a common scenario where after a successful dieting and exercising effort, you weight loss starts to plateau and eventually weight regain happens and you are back to your heavier self.
Why does that happen? Because you caved to your temptations? Lack of willpower to continue?
When you try to lose weight, your body will resist the effort, mainly through 3 ways:
1) Making you feel hungrier, craves certain food, and requiring more amount of food to feel full.
2) Slowing of body metabolism. Body will conserve energy to counteract weight loss
3) Muscles becoming more energy efficient. Hence, lesser calorie needed for doing activity.
These factors, combined will create a perfect storm for weight regain after a successful weight loss. These biological responses will persist even for many years to come! The more the amount of weight that you need to lose, the greater the resistance will be from the body
Therefore, for a lot of people they need the additional factor (pharmacotherapy, bariatric surgery, cognitive behavior therapy etc) to help them fight these natural body biological responses to weight loss.