Jill responded to my questioning of the way she used the phrase 'healthy weight'. I thought I'd take the opportunity to expand on my comments (because I'm ususally so brief with what I say).
I actually have two objections to the use of the term 'healthy weight'. One is that I don't think there's sufficent evidence that weight is an independent variable when it comes to longevity and the functioning of the body. The other is that even if weight was a good independent variable I think that using the term 'healthy weight' is hugely problematic. So this is going to be a post in two parts.
Weight as an independent variable
I actually think that Jill makes the point about the problem of treating weight as an independent variable in her comment.
Weight and health do not directly correlate. But at the extremes, weight does weigh on your health, whether one is anorexic or morbidly obese.What's interesting is that Anorexia is not a weight category, it's a mental illness and a set of behaviours. To say that anorexia does damage to your health is not a statement about size. You can have two women of exactly the same size, one of whom is damaging her health, the other whose not.
Now maybe being very skinny is an independent variable for a shorter life-span, certainly if you were living in times of famine it probably would be. But right now, in our society, we don't have actually know what relationship there is between being very small and having health problems. For example thin women are more prone to osteoperosis, but we don't know whether this is because lack of body fat causes osteoperosis, or that the behaviour that many women use to maintain their small figure causes osteoperosis.
I think the same analysis holds at the end of the spectrum. The correlation between being very heavy and increased death rates is regularly overplayed (in America by numbers with 6 figures in them). But even so correlation does not prove causation. Does weight gain cause illnesses, are there illnesses that cause weight-gain, or are both illnesses and weight-gain caused by a third factor (say poverty)? Until we have the answers to those questions we can't say that weight is an independent variable to our health. If we don't know that weight is an independent variable to our health then it is ridiculous to talk about 'maintaining a healthy weight'.
The word 'healthy'
Even if the evidence came in tomorrow that weight did definately cause health problems if you were at the extreme end of the spectrum, I'd stil be uncomfortable with feminists using the phrase 'healthy weight'.
We live in a world where eating disordered behaviour is frequently promoted as healthy. There are magazines here called 'healthy living' that are weight loss from start to finish and I've never seen a 'healthy food' section of a supermarket that wasn't entire diet products. Among middle-class circles in particular, where it's considered a little crass to talk about trying to lose weight, exactly the same conversations take place under the rubric of 'health' (I have a friend who comes from a more working-class background, and doesn't know the code, and she was mocked for talking about trying to lose weight - but if she'd talked about exactly the same behaviour in terms of health, it would have been completely acceptable).
I don't think we can ignore the fact that our society treats the phrase 'healthy' as if it is a synonym for 'thinner'.
I'd actually go a little further and question the usefulness of the word 'healthy' in most circumstances. Historically the word 'healthy' has been applied to many different behaviours, quite a few of which weren't going to promote your longevity (getting a tan, for example). The word 'healthy' ususally has nothing to do with promoting, and much more to do with promoting certain behaviours, ususally linked to some forms of social control.
Think about the ways people are most likely to use healthy - they'll say someone looks healthy, that food is healthy, and exercise is healthy. Most of the time what they're talk about has very little to do with vitality and longevity.
If someone says 'wow she looks healthy' then sometimes that means "great her eating disorder might not kill her", and most the time it means "She's lost weight, but it might be impolite to say so, so instead I will use an ingenious code that no-one will be able to crack." But It's not just someone's overall body shape that people describe as 'healthy'. We have healthy nails, healthy hair, healthy skin. Lets pause for a moment about the ridiculousness of describing dead cells as 'healthy'. When they're describing someone's appearance people ususally use the word 'healthy' in a way that has nothing to do with living long and prospering.
written before about how problematic I find using the term 'healthy' when it comes to food. But the same is true when calling exercise healthy. I've heard people describe exercise as healthy, even when it was damaging the body of the person who was doing.
This is all part of a wider problem, because the term healthy is usually only applied to individual behaviours, not structural problems. The biggest risks to us usually have absolutely nothing to do with what we choose to do as invidually, but the way our society is organised - poverty, food production, pollution, workplaces, housing standards and so on.
Some people who are fighting for structural change try and use the word 'healthy' to work for them - 'healthy workplaces' and 'healthy homes' are two examples. But actually I don't think this is particularly wise tactic. Lets name what we want from workplaces (that they don't kill us) and homes (that they're designed by people who remember that winter comes every year), rather than hide behind vague, nice sounding rhetoric.
Because fundamentally that's the problem with the word 'healthy' it's a very non-specific, but at the same time it is commonly used to mean something specific, which means you cannot use it, without it having another layer of meaning.