Junkfood Science: I think, therefore I am: Part Two

February 18, 2008

I think, therefore I am: Part Two

Could feeling badly about being fat be worse for your health than being fat? Researchers led by Dr. Peter Muennig, M.D., MPH, assistant professor at Mailman School of Public Health, completed an extraordinary study to examine the health effects of negative attitudes towards fatness and body acceptance. Their study appears in the March issue of the American Journal of Public Health.

Considering the evidence

Despite the popular assumption that body fat itself causes higher rates of hypertension, high cholesterol and the metabolic syndrome, “there is little evidence that this assumption is correct,” wrote Dr. Muennig and colleagues. This dearth of evidence is leading some scientists to challenge the adiposity (body fat) hypothesis. Instead of body weight, they said, “there is evidence that the BMI–health association is culturally produced.”

The very conditions associated with overweight and obesity, they said, are those also associated with the stress response: hypertension, heart disease, type 2 diabetes and high cholesterol levels. One reasoned explanation, they said, is that the stigma — fat prejudices — faced daily by fat people produces the stresses that risk their physical health. The heaviest people are most victimized.

Prejudices and discrimination against fat people is pervasive, occurring in social and public settings, employment, education, housing, healthcare and every facet of life, as they noted. [This was extensively documented in a 2001 issue of Obesity Research.] Fat discrimination isn’t just pervasive, the Mailman School of Public Health researchers wrote, it’s also severe. In one study they reviewed, 89% of obese people who’d recently lost weight said they would choose blindness over a return to being obese. “These stigma are likely internalized, leading to a negative body image that also may serve as a source of chronic stress,” said Dr. Muennig and colleagues.

Very real biological effects of stress have also been shown to be especially evident in fat people. In the researchers’ review of the medical literature, they found that the fat people who are disproportionately affected by negative body image concerns and social stigma are the same ones who are also most likely to suffer from BMI-associated morbidity and mortality. The serological markers of stress, such as C-reactive protein and fibrinogen, are also seen in high BMIs. These mediators of the stress response also play a central role in glucose metabolism, blood pressure regulation and lipid regulation, they explained.

Exploring where no one has gone before

Here’s where this study was unique and ingenious. It didn’t just look for correlations between BMI and poor health. Instead, they assessed how feelings of being “too fat” and wanting to lose weight, versus body acceptance and happiness with one’s weight — regardless of weight — influenced health.

Could the internalization of fat stigma and incessant anti-obesity messaging have adverse health effects, and could body acceptance be associated with better health?

If social stress about being fat is internalized into poor body images and feelings of unhappiness with body weight, the researchers hypothesized that this would be associated with poorer health — even independent of actual BMI. In other words, believing your body is unacceptably fat, undesirable or unhealthy, might actually be what’s bad for your health.

For this study, they measured the degree of happiness or dissatisfaction with one’s weight, using the difference between actual weight and what people wanted to weigh and felt was ideal for them. The researchers used 2003 Behavioral Risk Factor Surveillance System data on 170,577 U.S. adults for their analysis.

About two-thirds of adults in this country wanted to lose weight and only about 26% were happy with their current weight, the BRFSS data showed. Not surprisingly, women were more likely to feel badly about their bodies and want to lose weight (74%) than men (58%); and whites were more likely than any other ethnicity to be unhappy with their bodies and want to lose weight. Poor body image and the desire to lose weight rose with education level, younger age, and with BMI. Yet poor body image was found at all weights and nearly half of normal weight people wanted to lose weight, as compared to 76% of ‘overweight’ and 95% of ‘obese.’ [Sadly, although not included in their analysis, the BRFSS data found that one in eight U.S. adults who were underweight wanted to lose weight. For their analysis, they excluded those of low weight, BMIs <23, they thought might suffer from anorexia nervosa and skew findings.]

Despite older average ages, people who were happy with their weight experienced fewer physically unhealthy days (3.0 versus 3.7) and mentally unhealthy days (2.6 versus 3.6), compared with younger people unhappy with their weight. Those reporting that they were exercising had higher physically unhealthy days in all groups, possibly because of exercise-induced injuries, the researchers said.

Even after the researchers adjusted for actual BMI, age, education (socioeconomic status) and smoking, they found a direct relationship between feelings of being dissatisfied with one’s weight and more sick days. The worse people felt about their weights, the sicker they were.

Yes, this study was looking at correlations, but the relative risks were significant. Compared to those happy with their bodies, white women most dissatisfied with their weights had 450% higher risks for physically unhealthy days and 350% higher risks for mentally unhealthy days. Among men, the risks were 520% and 640%, respectively. For blacks, only women wanting to lose 50% of their weight were associated with a 460% higher risk of physically sick days.

Even among the oldest and heaviest people, those who were happy with their bodies and didn’t want to lose weight had no increased risks for sick days, mental or physical. If we were to stop looking at body fat as a health problem, Dr. Muennig told Reuters, “the problem may well disappear.”

As the researchers concluded:

Our finding that percentage of desired weight loss was a much stronger predictor of unhealthy days than was BMI further suggests that percentage of desired weight loss plays a greater role in generating disease than adiposity itself. Our study builds on a growing literature demonstrating that perceptions of one’s social acceptability and desirability can lead to health or disease whether this perception stems from being discriminated against, being poor, or being overweight.

[T]he relationship between percentage of desired weight loss and physically unhealthy days was more curvilinear among women than among men after age and BMI were held constant. Among men, negative body perceptions might be checked by social norms that suggest that social or intellectual accomplishments are more important than physique. Among women, whose social norms tend to emphasize the importance of physique, distorted notions of the “ideal” self may lead to a greater stress response.

Now, lest you suspect that the reason for poorer health, as reported by more sick days among those who wanted to lose weight, might have been due to actual health problems for which they’d been told to lose weight or feared they needed to lose weight “for their health,” the researchers tested this possible confounding factor in a number of ways. They excluded those who’d been advised by a doctor to lose weight; they excluded those who reported having diabetes or hypertension; and finally, they used actual diagnoses of hypertension and diabetes as endpoints rather that sick days — their findings didn’t change. The amount of desired weight loss was more predictive of each outcome measure than was BMI itself.

The implications of these findings for public health policy and for healthcare professionals are profound, they wrote. If the association between BMI and poor health is perceptual, public health messages that advocate idealized body types, and promote insupportable beliefs that obesity itself as unhealthy and that weight loss is effective or healthful, may be harming people. Their findings, if they’re replicated, they said, will add to the debate over the physiological effects of discrimination and inequality, such as perceived prejudices and lower socioeconomic status, and even extend to other areas of physical attractiveness.

“There needs to be a realization among public health officials and medical professionals that the messages we are giving the public could be doing more harm than good,” Dr. Muennig said to Reuters. “It has long been recognized that ‘fat’ does not necessarily equal unhealthy. Nonetheless, we doctors often have a very visceral reaction when we see an obese person in our office. This visceral reaction sets off a red light that says, ‘tell this person to lose weight.' That is not the right way to approach obesity.

In Part Three, we’ll examine some of the growing body of evidence mentioned by these researchers showing that internalized social stigma and perceptions of one’s social acceptability and desirability, lead to disease or health. Those very same health problems associated with the stress response and obesity, are also found among other groups in our culture most targeted by prejudices and discrimination.

© 2008 Sandy Szwarc

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