This statement is wrong. Muscle growth, in fact, is that the muscles are constantly tearing, and then replenished in time, equipped with adequate rest, and become bigger. So muscle gain is the process of muscle expansion.

Fat and muscle are two completely different tissues. Fat does not turn into muscle, and muscle does not turn into fat. Gain muscle, neither gain weight first, nor turn fat into muscle; Instead, first reduce the body fat rate through aerobic training, and then make muscles strong through strength training. Therefore, you don't have to gain weight first, but you must lose fat after gaining weight, otherwise your muscles will be covered with fat.