When food was scarce and expensive, they say, only the rich could afford to be fat. Thus, in the 19th century, well-do-do men with paunches joined Fat Men’s Clubs, which gave rise to the term “fat cat.” Heavy women of that era were stage stars. Lillian Russell, “airy fairy Lillian, the American beauty,” weighed 200 pounds.

Image Credit... Erik T. Johnson

Those notions of fashion gradually gave way to a more streamlined physique.

The sponsors of a 1904 contest to find “the best and most perfectly formed woman” settled on Emma Newkirk, an athlete from Santa Monica, Calif., who stood 5-foot-4 ¼, measured 35-26-36, and weighed 136 pounds. That would have given her a B.M.I. of 23.3 — not overweight, but close.

The body mass indexes of Miss America winners, according to a 2000 study, have been steadily decreasing since 1922, so much so that for most winners in the last three decades their indexes would cause them to be considered underweight.

How thin is thin enough? One Miss America had a body mass index of 16.9, which is considerably underweight. A woman of Emma Newkirk’s height would have had to weigh 99 pounds to have that body mass index. That may help explain why, in recent years, as many as two-thirds of women and more than half of men have expressed dissatisfaction with their weight.

How did we get to this point?

George Armelagos, an anthropologist at Emory University, calls it the King Henry VIII -Oprah Winfrey effect.

Henry VIII, king of England in the 16th century, “was huge,” he said, which was a symbol of his wealth. To get that way, Dr. Armelagos said, “it took 100 people collecting food for him and cooking it.” Compare that to the billionaire Oprah Winfrey. “She has to have a dietitian and cook and a trainer so she doesn’t get to be like that,” he said.

Today, poorer people are most likely to be fat and so, said Abigail Saguy, a sociologist at the University of California at Los Angeles, “fatness is associated with downward mobility.” Weight has thus become a moral issue couched in health concerns, she said. After a while, it almost becomes inconceivable that anyone would see a fat person differently.