BMI is useless – now what?

By Tatjana van der Krabben

Body Mass Index (BMI) is a very popular method in the medical field to see if you have a healthy weight.

With the metric system, the formula for BMI is weight in kilograms divided by height in meters squared. Since height is commonly measured in centimeters, an alternate calculation formula, dividing the weight in kilograms by the height in centimeters squared, and then multiplying the result by 10,000, can be used. Formula: weight (kg) / [height (m)]²

When using English measurements, ounces (oz) and fractions must be changed to decimal values. Then, calculate BMI by dividing weight in pounds (lbs) by height in inches (in) squared and multiplying by a conversion factor of 703. Formula: weight (lb) / [height (in)]² x 703

If the math is not your cup of tea, you can also use a chart like this: http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.pdf

With a BMI ranging from 25-29 you’re considered overweight. 30 and beyond you’re considered obese.

The problem with BMI
The BMI method is tricky, because:

1. It assumes that in order to assess a healthy weight all you need is a person’s height and weight
2.  Those who use it generally assume any and all excess weight can be shifted to eventually obtain an acceptable BMI
3. It is assumed that your BMI is an indicator of your general health

That would be…false, false and false. Although the last one is good news.

With a BMI of 30,5 I would qualify as obese. I don’t feel obese. I can tell you that much.

BMI means very little to me. If you have lipedema or lymphedema, the scales just don’t play along. This adds some, which you can’t lose just like that and which is giving a false BMI reading.

You don’t have to just take my word for it. Those in favor of the BMI index already acknowledge when very muscular, Asian or short or very tall, the numbers may be higher or lower than reasonably expected. For children and the elderly it may also give a false impression based solely on the numbers. I’m glad that’s being recognized now; when in my teens they happily calculated your BMI and rubbed the number under your nose. The list of people the BMI should not be applied to blindly is growing.

There is more and more debate on the BMI index. Not only that it yields a false reading for a substantial part of the world’s population, but also regarding the division of the scores, defining when your health is at risk because of your weight. There is an insightful study on the BMI index by Flegal et al (2012). General conclusion: medical professionals label you at risk too soon. The overweight category was even associated with significantly lower all-cause mortality. This is the abstract of that paper: http://jama.jamanetwork.com/article.aspx?articleid=1555137

As for indication of your general health when you have lipedema: lipedema fat does NOT affect your organs. If you have a lot of lipedema fat on your body, this will be a subcutaneous mass. Some women have reported back upon gastric surgery that the surgeons observed the internal organs to be in the same condition as in a thin person. So BMI is a poor indicator of general health in case of lipedema, among other.

Some health experts ‘already’ differentiate between unhealthy belly fat and the fat that accumulates on hips and thighs. There is growing room for some nuance, but be alert when in (insurance) paperwork you’re asked about height and weight. You can bet on it they will calculate your BMI. It’s the fastest, cheapest way to get some clue on your health. Or so it is believed.

Measuring the waist
Still, it’s useful to monitor your health. Lipedema doesn’t make you immune to unhealthy weight gain. I switched to measuring my waist. Lipedema was in legs and arms, so waist seemed a good place to monitor.

A waist of over 80 cm or about 31,5 inches makes you at risk of health problems, or so it says on the pages of different heart foundations. At 88 cm or 34,5 inches you are considered at great risk.

This seemed useful enough, until I realized I was unable to shift weight from my belly. Just over the belly button it was pretty much normal and you can still see a hint of my ribs. Obese, huh? Then I read Lipedema can (eventually) creep up to lower abdominal region. Here we go again. Even that boundary is now debated, with lipedema-like tissue reported or suspected in breasts, on stomach and even on the scalp.

Now I don’t want to fight my doctor every inch of the way; I do want to monitor my general health. Who needs fatty organs and clogged up arteries? If the lipedema is truly limited to your legs, you can obviously still measure your waist.

Edmonton Obesity Staging Scale (EOSS) – A different perspective
Recently I came across something different: EOSS. It was first introduced in 2009 in this paper: ‘A proposed clinical staging system for obesity’ by Sharma and Kushner. You can find the abstract here: http://www.nature.com/ijo/journal/v33/n3/abs/ijo20092a.html

There are 5 stages:
STAGE 0: Patient has no apparent obesity-related risk factors (e.g., blood pressure, serum lipids, fasting glucose, etc. within normal range), no physical symptoms, no psychopathology, no functional limitations and/or impairment of wellbeing.
STAGE 1: Patient has obesity-related subclinical risk factor(s) (e.g., borderline hypertension, impaired fasting glucose, elevated liver enzymes, etc.), mild physical symptoms (e.g., dyspnea on moderate exertion, occasional aches and pains, fatigue, etc.), mild psychopathology, mild functional limitations and/or mild impairment of wellbeing.

STAGE 2: Patient has established obesity-related chronic disease(s) (e.g., hypertension, type 2 diabetes, sleep apnea, osteoarthritis, reflux disease, polycystic ovary syndrome, anxiety disorder, etc.), moderate limitations in activities of daily living and/or wellbeing.

STAGE 3: Patient has established end-organ damage such as myocardial infarction, heart failure, diabetic complications, incapacitating osteoarthritis, significant psychopathology, significant functional limitation(s) and/or impairment of wellbeing.

STAGE 4: Patient has severe (potentially end-stage) disability/ies from obesity-related chronic diseases, severe disabling psychopathology, severe functional limitation(s) and/or severe impairment of wellbeing.

Sharma and Kushner propose a pragmatic approach ‘to managing patients at the different stages of obesity’. This is a rather top-down type approach. Their proposed course of action per stage is the following:

For STAGE O: Identification of factors contributing to increased body weight. Counseling to prevent further weight gain through lifestyle measures including healthy eating and increased physical activity.

For STAGE 1: Investigation for other (non-weight related) contributors to risk factors. More intense lifestyle interventions, including diet and exercise to prevent further weight gain. Monitoring of risk factors and health status.

For STAGE 2: Initiation of obesity treatments including considerations of all behavioral, pharmacological and surgical treatment options. Close monitoring and management of comorbidities as indicated.

For STAGE 3: More intensive obesity treatment including consideration of all behavioral, pharmacological and surgical treatment options. Aggressive management of comorbidities as indicated.

For STAGE 4: Aggressive obesity management as deemed feasible. Palliative measures including pain management, occupational therapy and psychosocial support.

In his blog dr. Sharma mentions that this staging system is to be used together with the conventional BMI ‘cutoffs’. That's a bit disappointing after his explanation that BMI didn’t cut it and something else was needed. Still, you need a starting point when you should start evaluation to assess the correct stage. Otherwise all is pretty conventional as well: if it gets bad, start popping pills and put bariatric surgery on the table.

The good news would be that through the staging system a doctor actually should to look at you and do more tests, to see how you are actually doing and feeling. I would have to applaud Sharma and Kushner for that: it’s a great start. ‘Plus size’ is not by definition the same as ‘plus problems’. They got that right. Lipedema doesn't exactly make you a care-free, pain-free happy camper, but it certainly doesn't have to coincide with the health problems typically related to obesity.