Healthy Redefined Part 1: Measuring the Obesity Crisis
From unfortunate fat-shaming in Georgia’s “Strong4Life” campaign put on by Children’s Healthcare of Atlanta to kids being graded on their weight in public schools across the country via their BMI score on their report cards, we see well-meaning people using harmful and ineffective strategies like crazy to try and counteract this country’s weight problem. This overwhelming focus on body size has stolen the spotlight in mass media and scholarly research since the mid-‘90s, all citing an imperative to end an obesity crisis that has been championed by the federal health agencies.
With the health and fitness of the nation as the key justification for calling high levels of obesity a “crisis,” it is important to understand how bodily health is defined in research. How is health measured? What defines a healthy or physically fit body? In a country where both obesity and eating disorders have skyrocketed simultaneously, it is crucial to understand how physical health has been and is being understood, tested and promoted.
Scholars are concerned that very little evidence has been produced regarding the question of exactly how body fat is supposed to cause disease (1). With the exception of osteoarthritis, where increased body mass contributes to wear on joints, and a few cancers where estrogen originating in adipose tissue may contribute, causal links between body fat and disease remain hypothetical. Researchers are asking health professionals and policy makers to consider whether it makes sense to treat body weight as a barometer of public health. Despite this shaky foundation for defining physical health in terms of body fatness, much of current health and communication research measures health through simple measures of a person’s body fat, and that may be doing more harm than good for the health status of this country.
Defining Health: Body Fat = Body Health?
Researchers measuring health in terms of body fat generally rely on the American Council on Exercise’s guidelines to determine which percentages are healthy, with anything below 10% and above 31% in women (or below 2% and above 24% in men) considered a health risk. Direct measures of body composition estimate a person’s total body fat mass and fat-free or lean mass through MRI, underwater weighing, CAT scan, and other methods. Power, Lake & Cole (1997) said, “an ideal measure of body fat should be accurate in its estimation of body fat; precise, with small measurement error; accessible, in terms of simplicity, cost and ease of use; acceptable to the subject; and well-documented, with published reference values.” They go on to state that “no existing measure satisfies all these criteria.” Since these methods are expensive and invasive, they are rarely used in research. Because of this, scholars are much more likely to rely on indirect measures of body composition, including the most popular of them all: Body Mass Index (BMI).
Indirect techniques for measuring fat include all the most common ones: waist and hip measurements, skinfold thickness, and indexes of measured height and weight such as BMI. These measurements are only a surrogate measure of body fatness, yet they are commonly used to represent not only adiposity but also health and fitness in research and media discussion about healthy bodies. The life and health insurance industry, medical practitioners, researchers, health specialists and seemingly everyone else on the planet uses the BMI to measure people’s health. That’s because it is the international standard for judging healthy weight, as upheld and promoted by the CDC, NIH and WHO. This is bad.
Here are 10 quick reasons why the BMI is a shockingly terrible measure of health:
The equation used to calculate BMI (the ratio of an individual’s weight to height squared) was developed in the 19th century by Quetelet, a French scientist who warned the calculation was only meant to be used for large diagnostic studies on general populations and was not accurate for individuals.
The BMI’s height and weight tables used to tell you what your score means came from the life insurance industry. Yep. A standardized table of average weights and heights was developed first in 1908, when life insurance companies began looking for ways to charge higher premiums to applicants based on screening by their own medical examiners. By setting the thresholds for “ideal weight” and “overweight” lower than what mortality data showed as the actual healthy weight ranges, they were able to collect more money for those they deemed “overweight.” In 1985, the NIH began defining obesity according to BMI, which defined the 85th percentile for each sex as the official cutoff for what constitutes “obese,” based on the standards for underweight, average, overweight and obese that were set by the 1983 Metropolitan Life Insurance Company mortality tables (Williamson, 1993).
The NIH implemented the BMI standard under the theory that it would simply be used by doctors to warn patients who were at especially high risk for obesity-related problems (2). It was never meant for individuals to calculate their BMI and accept it as a diagnosis of whether or not their weight is healthy, yet that is EXACTLY how it is used today. Individuals are encouraged to easily diagnose their own BMI status through the NIH website-hosted BMI calculator.
Those weight tables are based on the unfounded idea that any weight gain after age 25 is unhealthy. Though weight tables before the mid-1900s allowed for increasing weight with age (which naturally occurs), the Metropolitan Life insurance Company became the first to deem an increase in weight after age 25 as undesirable and unhealthy – again, to collect higher premiums. Also, the BMI is advised to be used only for people older than 20, due to the changes young bodies undergo before that age, yet it is very often used to diagnose adolescents and teens. Researchers admit that it is unclear at what level of body fat health risks begin to rise for children (Denney-Wilson et al., 2003), so trying to define a standard of what constitutes overweight and obese for children is incredibly difficult.
Those weight tables also did not take into account body frame or build, unlike previous tables, which included “small,” “medium” or “large frame” due to demands from physicians who rightfully wanted to avoid serious miscalculations of body fat (Cziernawski, 2007).
Those same 1983 tables (and now our BMI) also failed to take gender into account, despite healthy levels of fat and weight distribution differing greatly between males and females (3).
BMI is based on a Caucasian standard. It is proven to be highly inaccurate for other races and ethnicities. In particular, in some Asian populations, a specific BMI reflects a higher percentage of body fat than in white or European Ppulations (James, 2002). Some Pacific populations and African Americans in general also have a lower percentage of body fat at a given BMI than do white or European populations (Stevens, 2002). Even the WHO has acknowledged the extensive evidence that “the associations between BMI, percentage of body fat, and body fat distribution differ across populations” (WHO, 2004).
In 1998, millions of people considered of “normal” weight were suddenly re-classified as “overweight” the next day when the NIH lowered the threshold for “overweight” and “obese” by 10 lbs. They based this change on the vague claim that studies linking extra weight to health problems warranted the changes (Cohen & McDermott, 1998). On June 16, 1998, the “average” woman was 5 feet, 4 inches tall and weighed 155 pounds. On June 17, a woman of that same height and weight became “overweight.” The requirement for “average” dropped 10 pounds to 145, and a person of the same height who weighed 175 pounds was considered “obese.”
Experts say it’s “useless.” Dr. David Haslam, the clinical director of Britain’s National Obesity Forum, said, “It is now widely accepted that the BMI is useless for assessing the healthy weight of individuals” (4). Despite extensive evidence proving the BMI lacks accuracy for calculating an individual’s body fat (4), A growing pool of evidence suggests that BMI is a “crude tool” for judging individual health that “fans fears of an obesity epidemic even as it fails as a reliable measure of an individual’s health” (Heimpel, 2009). Even the U.S. Preventive Services Task Force concluded there is insufficient evidence to suggest BMI screening can be used to prevent adverse health outcomes (4). Prentice & Jebb (2001) illustrated a wide range of conditions in which “surrogate anthropometric measures, especially BMI, provide misleading information about body fat content, including infancy and childhood, aging, racial differences, athletes, military and civil forces personnel, weight loss with and without exercise, physical training and special clinical circumstances.” More and more studies are showing the fact that people in the “overweight” and even “obese” categories of the BMI are at much lower risk of death than those in the “underweight” and even “normal” categories. So why do we keep measuring health based on BMI?
Despite all the evidence against it, government health agencies defend the BMI as the national standard for judging healthy weight due to the fact that it is “inexpensive and easy for clinicians and for the general public” (CDC, 2010). That’s exactly why researchers use it so consistently as a stand-in for “health.”
It is imperative to keep in mind that the much-publicized U.S. obesity crisis has risen to the forefront of national attention only since the late ‘90s, after the NIH changed the standard for what constitutes overweight and obesity. Using data gathered from 1976-1980 and comparing it to data from 1999-2002, the CDC reported that obesity doubled from 15 to 31 percent between 1980 and 2002 (CDC, 2007). It is unclear whether the data was compared using the same standard for determining “obesity,” since the criteria for fitting into this category changed in 1998 to include many more people that were previously considered merely “overweight.” Though obesity remains at the forefront of national health concerns and media discourse of Americans’ health, the rate of obesity hasn’t changed in a decade. It plateaued since the most recent CDC report, with no change between 2003 and 2006, when the most recent national data was gathered (Heimpel, 2009; CDC, 2007).
Unfortunately, heart disease, cancers and diabetes remain serious threats to public health, and obesity is considered a risk factor for these chronic illnesses. So if the BMI is worthless, then what do we use to measure or determine bodily health? The No. 1 step is to quit measuring and start exercising. That brings us to the incredibly important Part 2 of this Healthy Redefined series. But if you just can’t stop measuring, one step in the right direction is just as easy to calculate and much more accurate than BMI: waist circumference (WC). It is a more specific marker of upper body fat accumulation than BMI and is correlated with lipid abnormalities (O’Connor et al., 2008). When the researchers were evaluating a weight management program for overweight and obese adolescents, O’Connor et al. (2008) found a significant decrease in waist circumference, but not BMI, in participants. Janssen et al. (2004) evaluated WC in assessing obesity-related health problems and found that waist circumference is more effective than BMI at explaining obesity-related health risk. They found that people who are overweight or obese according to the BMI often have the same level of health risk as normal weight people with the same WC value.
Though WC is a step in the right direction and closer to measuring health, it still isn’t quite there. The next step is to redefine what this crisis is really about. It’s about health, not body size. During the time the obesity crisis has been in the forefront of media and federal health agency initiatives, the diet and weight loss industries have thrived unlike ever before. Simultaneously, fat-shaming/thin-ideal-promoting media have also flourished, with female body image hitting an all-time low. With lost self-esteem, lost money and time spent fixing “flaws” and a well-documented preoccupation with thinness among females of all ages, the effects of profit-driven health information involve serious loss for women, while too many industries see huge economic gains. From the life insurance industry collecting higher premiums from those they deem “overweight” based on a standard they set themselves, to major financial savings for medical experts and the government using the profit-driven BMI, to the diet and weight loss industry raking in more than $61 billion on Americans’ quest for thinness in 2011, those who make money off the discourse surrounding women’s health are thriving unlike ever before.
With so much evidence showing that our obsession with body fat is missing the mark for health and well-being of all sorts, I argue that we need to do away with the title “obesity crisis” all together. This crisis isn’t about too many people meeting an arbitrary standard of body fat, this crisis is about poor health due to unhealthy choices defined most prominently by inactivity and poor diet. Measuring health according to activity level is the most promising step for getting an accurate gauge of true wellness. But FIRST, we must focus on getting rid of barriers like “feeling too fat to exercise” and not knowing if you can be successful in order to make way for real success! Next Up – Healthy Redefined Part 2: Forget Fat and Get Fit!
Kite, Lindsay. (2011). Redefining Health Part 1: Measuring the Obesity Crisis. The Beauty Redefined Foundation: www.beautyredefined.net/redefining-health-part-1References 1) Campos et al., 2006; Rothblum et al., 1999; Saguy & Riley, 2005; Shugart, 2010 2) Devlin, 2009; Singer-Vine, 2009 3) Prentice & Jebb, 2001; Czerniawski, 2007 4) Devlin, 2009; Bailey et al., 2008; Czerniawski, 2007; Gerbensky-Kerber, 2011; Nihiser et al., 2007 See also: Body Mass Index, Diabetes, Hypertension, and Short-Term Mortality: A Population-Based Observational Study, 2000–2006 (released July 2012): http://www.jabfm.org/content/25/4/422.full