In the aftermath of World War I, American society was forever changed. Women who filled the roles of male employees while men were off at war had felt what it was like to shed their heavy layers of dress for something more practical. Additionally, the 19th Amendment had just passed, and white women were now allowed to vote. 

This new autonomy and less societal pressure from men opened up new doors for women's fashion and changed the beauty standards. A curved female figure was swapped for a slender, boyish one. Clothes were more loose-fitting and encouraged movement. Women had an active nightlife where they drank, danced, smoked, and flirted at speakeasies and jazz clubs. 

Yes, women were free of oppressive corsetry and the weight of long draping gowns, if they so chose. However, that doesn't mean that their body was completely free. The physique itself was now under scrutiny, and had to be controlled through diet, exercise, and shapewear. In the Victorian era, women could push their weight to desired areas and keep these devices hidden through modest clothing. Now, with more revealing garments, women had to make internal changes to follow beauty standards.