Body Mass Index (BMI): Where It Came From and What It’s Good For

The body mass index (BMI) has become the most-used means of determining whether we are overweight or not, supposedly by measuring our body fat. Plug your height and weight into a BMI calculator and you’ll get a quick and dirty “definitive” answer. But where did BMI come from and how useful is it really?

BMI was invented in the 1800’s by a Belgian polymath named Adolphe Quetelet. It’s a mathematical calculation dividing a person’s weight by the square of his/her height. He was doing social research on what the “average man” looked like. His research had nothing to do with health. He was researching a lot of things, like a man’s arm strength or the age he marries.

The “pioneers” studying and pushing BMI for profit? Insurance companies. In the early 1900’s, motivated by their bottom line, life insurance companies started doing studies of BMI to show overweight people were more likely to have health problems and die earlier to show their policy holders.

In 1972 a professor and researcher named Ancel Keys published his paper “Indices of Relative Weight and Obesity.” He examined height-weight formulas and determined Quetelet’s was the best. Keys gave Quetelet’s formula the name “body mass index.”

BMI caught on. Instead of being used as studies of population health, doctors began using it as a quick way to measure body fat. But Keys had actually warned in his paper against using BMI for individuals diagnoses, since the equations ignores a lot of other variables, like exercise and ailments like high blood pressure. The Center for Disease Control (CDC) notes that BMI is only one factor to consider in determining weight problems:

BMI is used as a screening tool to identify possible weight problems for adults. However, BMI is not a diagnostic tool. For example, a person may have a high BMI. However, to determine if excess weight is a health risk, a healthcare provider would need to perform further assessments. These assessments might include skinfold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screenings. Continue reading

Should Parents Lose Custody of Obese Children?

It’s things like this that sometimes make me ashamed to be a lawyer. Seriously. There’s been a lot of media talk lately about how parents are using their childrens’ obesity (and blaming their spouse for causing it) as leverage in custody battles.

But let me backpedal a bit first. Earlier in the year, the issue was whether parents should lose custody of their extremely obese children, who would be put into foster care. This issue was raised in an opinion piece in the Journal of the American Medical Association, written by Dr. David Ludwig, an obesity specialist at Children’s Hospital Boston.  Ludwig claims that the point isn’t to blame, but to act in the child’s best interest and provide help parents can’t provide. He states that the goal is to reunite the family and perhaps provide parenting instruction.

Ludwig focuses on a few “extreme” examples in which authorities should intervene. Scary stories like a three year old girl who weighed ninety pounds and reached 400 pounds by the age of twelve. A fourteen year old boy who weighed 555 pounds. Sensationalism calculated to put fear in peoples’ hearts as a means of breathing air into his argument.

He believes existing child protection laws are enough to carry out his recommendations. Children welfare agencies and foster care are already overburdened and children aren’t getting the protection they need. Do we really want to make matters worse? Continue reading

Talking About Fat Talk

Most of us have done it. I know I have. “I’m so fat,” you might say. Or your friend might complain to you that “my ass looks good in these jeans.” Then we reassure each other that “no, you’re not fat” and “really, you look great.” Fat talk. The recurring dialogue between women talking about how overweight and bad about our bodies we feel.

I read a study published in the Psychology of Women Quarterly recently about the hows and whys of womens’ fat talk. They interviewed college women about how they feel about their bodies and their feelings and thoughts about fat talk. The findings and conclusions the study came to were really interesting:

Do overweight women fat talk more than thinner women?

No. The study found no connection between womens’ body size and how often they complained. In fact, thinner women complain more. The study theorized that heavy women are less likely to complain because they don’t want to draw attention to their weight.

Who is fat talking the most?

The women who are the most unhappy with their bodies.

What reason did the women interviewed give for their fat talking?

The women studied said that fat talking relieved stress related to their bad body image. They also do it to be part of a group. Everyone’s talking about it, so they feel obligated to chime in. The study also suggested that women might be feeling bad about a variety of things and zone in on fat talk as a focal point for venting their overall bad feelings. Women might also fat talk before or after eating to provide an “excuse” or “apology” for their guilt about eating.

What did the women say they hoped to gain from their fat talk?

The majority of women wanted to be reassured that they weren’t fat and have their friend(s) compliment them (tell them how good they looked). A much smaller number hoped for emotional support such as advice on how to get thinner/feel better, or an offer to work together (like dieting or working out together). About 25% of the time, women do start working out or dieting together, but it hasn’t been studied whether they keep it up.

Why does fat talk make us feel worse about our bodies?

The study suggested that maybe it’s because the more unhappy we are with our bodies, the more we talk about it. Another possibility is that talking about it makes us feel worse because we are dwelling on it. Even if you don’t bring up the topic, having someone else raise can remind you of your insecurities and make you dwell on the subject, thinking “If she’s fat, then what am I?” Continue reading

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