Someone is referred to as ballet body when they have a thin body type. But lean body type can be distinguished into healthy and non healthy body type. If you are very thin and have no curves in the body, then you will not be looking good and also it is not good for health. So having ballet body not necessarily mean you are lean and healthy. It can have complications as you will be having long and lean limbs which will not be attractive. Ballet is a perfect artform which requires some physical attributes like very nice flexible ankles and feet and also you will need to be athletic which will help you in maintaining a good shape in your body. If you want to have ballet body, be sure to gain some weight which will make you look healthy.