At first, you will lose water, but after a while, you will start to consume fat, fat factors will decompose, and you will also produce water. You should insist on exercising at will. Don't think you are burning fat if you don't eat, because if you don't eat for a long time, if you eat too much at once, it will not only make your stomach swell, but also absorb more. Proper exercise and proper diet control are the only way to lose weight.