All of that is to say that weigh loss through calorie reduction is not an effective means for permanent weight loss, and is actually damaging the body's metabolism every time weight is lost and then gained back. Transforming one's own body is so much about the food than it is about the quantity being eaten. A notable exception might be if one is morbidly obese, and their calorie intake is 8000 calories per day, then they should be cutting back calories (if they are not an olympic level athlete). By no means though should that person be cutting back to a 1200 calorie diet.
I personally believe that 80% of weight loss comes from diet (that's not calorie reduction, but changing how one eats), and 20% comes from physical activities like walking, and weightlifting.
In my opinion, the four best things anyone can do to achieve sustained and healthful weight loss are:
- Eating healthily (i.e. eating real food, and drinking water).
- Walking (slowly, and low-impact).
- Getting 8 hours of restful sleep (preferably in a pitch black room, with as little ambient light as possible).
- Developing strong stress management skills (breathing exercises, physical activity, reading... whatever is relaxing and stress relieving).