The first law of weight loss

The first law of weight loss is the following. Whatever you consume must be either spent or stored. In other words, the food (calories) that you eat is either used up to produce energy for your body functions and physical activity or stored as fat. There is no way around that. You either spend it or save it. Your weight always depends on the balance of what comes in and what comes out. If you consume more calories than you spend, you gain weight; if you consume less than you spend you lose weight.

Therefore, any conceivable weight loss and maintenance strategy (with the exception of liposuction) has to do with either burning more calories and/or consuming less calories.