Letting go of the “ideal” body weight

Read through the research literature on eating disorders–especially anorexia–and you won’t be able to avoid the phrase “ideal body weight.” Weights are expressed as “% IBW.” Treatment is measured as to whether sufferers are able to return to 85%, 90% or 95% (pick one) of “ideal body weight.”

It’s a phrase I seriously hate.

In many of these studies, the researchers calculate ideal body weight as the 50th percentile BMI-for-age in adolescents and/or healthy weight charts from the health insurance industry. That are generally 50 years old. They are also frequently used as estimates for weight goals when treating patients.  Hey, they’re supposed to be “ideal,” right?

Here’s the thing: the 50th percentile for weight or BMI is only “ideal” for the one percent of the population that happens to naturally fall along that percentile. For others, it’s either an over- or underestimate of weight. I understand that there’s quite a lot of guesswork when it comes to setting appropriate weight restoration goals for a person, and the 50th percentile is probably not a bad place to start for lack of other data BUT can we at least admit that it’s a guess and not some sort of ideal?

Then there’s the ideal body weight. A singular weight. It’s stupid. A woman’s weight can vary by 5-10 pounds during her menstrual cycle. Been there, done that, got the t-shirt (and baggy sweatpants).* Our weight can also vary by our hydration status, time of year, and any number of things. When I was in treatment for the second time, I was given a target weight that was X.5 pounds. Seriously? I thought it was the people with eating disorders who were ridiculously uptight and precise about body weights.

Lastly, when you’re dealing with something like ideal body weight, there’s the thorny issue of “ideal”. Exactly whose ideal are we talking about? Cultural ideals? That strikes me as silly. Health ideals? Maybe, but, again, there appears to be a fairly wide range of body weights at which someone is at “ideal” health.

Some treatment professionals had actually set my target weight by asking me what I wanted to weigh. Asking someone who just carved “pig” into her stomach with a razor blade what she thought her ideal weight was strikes me as peculiarly short-sighted.

Other professionals determined my “ideal” weight using the formula that said the “ideal” weight for woman is 100 pounds for five feet and 5 pounds for each additional inch. Certainly there are some people for whom that is accurate, but it isn’t for me and a lot of people I know.

I spent years during my illness at weights the broader culture deemed ideal and at weights treatment professionals thought were ideal (news flash: it’s generally not healthy for a grown woman to weigh what she did when she was 12, yet no one ever objected or even thought it was a problem. No, I wasn’t a scrawny 12-year-old, but still…). The problem is that the  idea of ideal body weights come with a hella lot of cultural baggage. So many ED professionals talk up how bodies can be healthy at many different sizes, that our current cultural obsession with obesity isn’t doing anyone any good, yet they routinely calculate ideal body weights for people with anorexia as being ludicrously low. You can’t get away from the obesity phobia.

So if we’re not going to use “ideal” body weights, what’s the alternative? Target weights? Maybe, but for adolescents, targets aren’t stationary.  I think we need to let go of these ideals and targets and focus more on weights that are biologically appropriate for each patient. Some people are tall and lean, others are shorter and stockier. Each person will have a weight range that is biologically appropriate for them. It’s not about ideals or judgements or targets or whatever. It’s just reality.

We need to let go of the idea that all people with anorexia are going to have weights that naturally tend towards the lower end of the “normal” BMI spectrum. We need to stop assuming that “not underweight” means that a person is at a weight that is appropriate for them. We need to be aware that some people have biologically appropriate weights that are even above BMI 25. And that’s okay.

In a world of 7 billion people, there isn’t an ideal body weight. It varies. And the sooner we accept that, the better we’ll all be.