First of all, the way to think about the societal piece, especially when you think about the genetics of these illnesses, is that anorexia nervosa is one of the most heritable psychiatric conditions. The heritability is about is about 75%. The heritability of schizophrenia, for example, is about 50%. The heritability of sugar diabetes is about 70%. It's a highly genetically determined disease. Genetics loads the gun, and environment pulls the trigger.
Since the early 1960s the ideal for female beauty has been an unrealistically thin ideal. There's a bellwether; that's a sociological term for a single person who resets a societal trend. This person was Twiggy in the early 1960s, who literally overnight reset the expectation for what a woman should look like, as compared to someone like Marilyn Monroe, five or six years previously, who at five feet six inches weighed 135 pounds and everyone thought that was fine, thank you very much.
By the time you get to the early 1980s, if you can think of that Jane Fonda 20-minute workout image—everybody knows that image—she's five feet seven inches and weighs 115 pounds, which meets a diagnostic criteria for anorexia nervosa, by the way, and she did have anorexia for many years. She's fessed up about that.
There was this massive sudden change. I've been watching this, obviously because of what I do for a living, for 25 or 30 years.
In the 1990s we thought we were getting out of it because there was a brief interest in muscularity and strength for women. That went on for about five years, from 1990 to 1995. The AIDS epidemic starting in the late 1980s certainly made it not particularly attractive for men to diet and lose weight, because if you lost weight everyone thought you had AIDS. That resolved itself after about 10 years. The female muscularity thing very rapidly turned into leanness and muscle definition and went straight back to calorie-reduced dieting.
I wish I could say that this is changing, and sooner or later it will change, because a preference for body weight and shape is like hemlines or hair length: it is a fashion statement. It keeps getting gussied up as a health issue, but it's not. It will eventually change. It's relatively recent in our history, only about 50 years, but there's very little evidence that it's changing right now.
Education about attitudes to weight acceptance and so on is very important, but they are being plowed under right now by a belief that we have an epidemic of obesity, especially in children, which frankly isn't true. It's very complex.