The body must exert energy in order to shed fat, but why does it store the fat in the first place?  If your metabolic rate is low and you don’t exercise much, then your muscles don’t require energy.  Since your muscles don’t require energy then why would your body bother burning calories?  It will just store and accumulate fat.  You need to trick your body into believing that your muscles are overworked so it can start burning those calories to rejuvenate it.  Overworking your muscles for short intervals you will do just that and as a result, you will increase your resting metabolic rate. While you are resting your body is still burning high amounts of calories. This is how your body becomes a fat burning furnace.  Eating less is not a fast solution to obesity because your body will hold onto the accumulated fat since it believes it might need to burn those fat calories just for survival. Although you may not gain weight, you will definitely not lose fat.