Some historians and social critics say our obsession with thinness is based less on science than on morality. They equate our society's stigmatizing of obese people (treating them as "sick," disabled, or weak) with the Salem witch trials or McCarthyism (the paranoid anticommunism movement of the 1950s). These critics argue that the definition of obesity has often arbitrarily shifted throughout history.

Indeed, being slightly overweight was once associated with good health (as we've seen, in some parts of the world, it still is) in a time when many of the most troubling illnesses were wasting diseases such as tuberculosis. Plumpness used to be associated with affluence and the aristocracy

(King Louis XIV of France padded his body to look more imposing), whereas today it is associated with the poor and their supposedly bad eating habits.195