Needless to say, models and fitness instructors need to control their body shape. In the circle, they should control their daily meat intake. They should not eat too much meat or drink too much water. Otherwise, they can't control the golden ratio. Although they earn a lot, it is a great burden to their health. Fitness instructors should be lower, bigger and show their muscles. Generally speaking, the requirements are enough. What is more important is the understanding of professional knowledge and the attitude towards students.