If you are dieting to lose weight, the weight you just lost is actually the weight of water. The content of water in human body is as high as 70%. If you lose ten kilograms, then two kilograms are water. If you just go on a diet, you won't burn too much fat, so you lose water in the early stage. If you control your diet and exercise at the same time, you will lose 5 kilograms, only 1 kilogram of water, and most of it is fat. When we lose weight, our fat starts to burn, which means that when we lose water, fat won't burn. Fat will slowly fall off at first, because our body needs fat to meet daily life. After we exercise to lose weight for a period of time, the body will burn fat when it adapts, and then lose weight faster.