With age, after pregnancies and in obesity the elasticity of the connective tissues and skin can decrease resulting in folds and rolls on the abdomen. After heavy weight reduction the same phenomenon can occur with skin hanging like an apron. There are no physical activities or medicines capable of tightening the skin. But also here we can help.

You don't have to walk around with sagging skin on the tights. The skin redundancy is commonly located at the inner sides of the thights or in some cases all the way around.

The ideals of beauty changes with every person. There are persons wanting big, powerful buttocks and others would like to have small and tense ones. 

 After weight reduction the elasticity of the skin might be insufficient to redrape the skin over the new volume of the body. This is often seen in the face, on the neck, arms, abdomen and thighs.
The same sagging of the skin can occur with agening. Sagging skin on the arms and on the thighs is often considered unaesthetic and embarrassing and skin redundancy can only be corrected by excision.

The proportions of the body do not always represent the individuals own expectations or ideals. The inborn numbers of fat cells remain constant through life and they are located where they have been placed by nature. Thus, more or less visible fat deposits can persist in areas where you do not want them to be in spite of weight reduction.