Fashion designers work to a fantasy of what the human body looks like. They are taught how to draw human figures in a distorted, idealised way. The two figures in the middle are typical of fashion design drawings. Designs are based on these oddly proportioned, fantasy, body shapes.
The figures on either side were statistical averages from a series of anthropometrics studies done with US military personnel. Whilst limited to a select age range and profession, these nonetheless are based on measurable and observable reality. These are real body shapes. ( From Human Dimension & Interior Space by Julius Panero and Martin Zelnilk)