If you focus on muscle exercise, you will gain weight, but your appearance will not become fat, but more symmetrical, because the density of muscle is much higher than that of fat. If aerobic exercise is the mainstay (such as running, aerobics, etc.). ), then you don't have to worry about weight at all, because it is an excellent way to lose weight and shape up. It should be noted that when doing muscle exercises, we should pay attention to the balance of the whole body muscles, not just the upper body, which will lead to the situation of big arms and small skinny legs, and consciously practicing leg muscles is also beneficial to the growth of the whole body strength.