People remain fatter because adults have given up on losing weight - and it's society's fault

A study of 27,350 adults drawn from the National Health and Nutrition Examination Survey (NHANES) finds that adults are not trying to lose weight. 

Part of that is cultural. We said women and men in media who were thin were sending an unrealistic body image to everyone else, it was "fat shaming" and they are probably anorexic anyway.

We enabled obesity and it worked. 

 The trend in the percentage of adults who were overweight or obese and trying to lose weight were assessed during three periods: from 1988-1994, 1999-2004, and 2009-2014. Participants ages 20 to 59 years who were overweight (a body mass index [BMI] of 25 to less than 30) or obese (BMI 30 or greater) were included. The question of interest was "During the past 12 months, have you tried to lose weight?" Overweight and obesity prevalence increased throughout the study period, from 53 percent in 1988-1994 to 66 percent in 2009-2014. The percentages of adults who were overweight or obese and trying to lose weight declined during the same period, from 56 percent in 1988-1994 to 49 percent in 2009-2014. 

The largest decline occurred among black women, from 66 percent in 1988-1994 to 55 percent in 2009-2014. Black women also had the highest prevalence of obesity, and more than half of black women (55 percent) were obese in the 2009-2014 survey. Adjusted prevalence rates showed a significantly declining trend of reporting efforts to lose weight among white men and women, and black women.

Link: doi:10.1001/jama.2016.20036