Earlier this month, Annals of Internal Medicine published a metaanalysis titled “Are Metabolically Healthy Overweight and Obesity Benign Conditions?” (Kramer et al, 2013). This study pooled the results of 8 previously published research studies to conclude:
“Compared with metabolically healthy normal-weight individuals, obese persons are at increased risk for adverse long-term outcomes even in the absence of metabolic abnormalities, suggesting that there is no healthy pattern of increased weight.”
If you are the average reader- even many scientific researchers- this may be the only sentence of the study that you read. Even worse, you may only read the news reports on the study, not the actual research study itself. We all want to "get to the punch” and find out the big news without digging around in the actual article. This becomes problematic when the authors’ punch line and the media headlines do not line up with the results of the study. This paper is a perfect example.
The media was off and running with headlines blaring fat is bad. CBS News used the headline “Can you be obese and healthy? Study says no.” Fox News chose “There’s no such thing as healthy obesity” (illustrated with a headless fat woman riding an escalator- she’s obviously too lazy to take the stairs and too ashamed of being fat to show her face). NPR reported the headline “Overweight and healthy: a combo that looks too good to be true” (but kudos to NPR for illustrating the story with a fat person exercising on a treadmill!). NBC News went with “New research disputes fat but fit claim.”
But is this what the study really showed? Before we get into the results, it should be noted that the researchers did not account for any variables that mediate the relationship between BMI and health, such as physical fitness, nutrition, medical care, age, etc... So it is very difficult to really know much about anything based on this general analysis. Nonetheless, I’ll share their results. They found that all people who are metabolically unhealthy are at a statistically similar increased risk for mortality and cardiovascular events, whether they be normal weight, overweight, or obese. In fact, people who are normal weight and metabolically unhealthy are at the most elevated risk. This blog post does an excellent job of explaining the real findings from the study. She orders the groups that the study examined based on their risk of mortaility or cardiovascular event relative to the comparison group, from least to most at risk:
Metabolically Healthy- Normal Weight: 1.00 (this was the comparison group)
Metabolically Healthy- Overweight: 1.21
Metabolically Healthy-Obese: 1.24 (this was the statistically significant finding that made all the headlines; they have 24% increased risk compared with the metabolically healthy normal weight group)
Metabolically Unhealthy- Obese: 2.65
Metabolically Unhealthy- Overweight: 2.70
Metabolically Unhealthy- Normal Weight: 3.14 (this finding didn’t make any headlines; they have 214% increased risk relative to the comparison group)
As you can see, all groups of metabolically unhealthy people are at far greater risk than the metabolically healthy obese people (214% greater risk vs. 24% greater risk). Perhaps the real headline should have been “It is unhealthy to be unhealthy at any size but especially if you are thin!” Not quite as glamorous, huh? Despite results of the study showing that people who are overweight and metabolically healthy are not at significantly increased risk compared to their normal weight metabolically healthy peers, the lead author of the study Dr. Caroline Kramer stated:
“It is not okay to be overweight. It is not okay to be obese.”
Did she read her own results?? The research article and an editorial accompanying it published in Annals of Internal Medicine promote weight loss for all, regardless of health. The authors and media were silent on how to help the group most at risk, which are the normal weight metabolically unhealthy people. There is not a $265 billion global weight loss industry to support that result. Unfortunately, there is little research that shows that most people can sustain long-term weight loss and maintenance. In addition to being ineffective, dieting and other weight loss strategies can lead to weight gain, disordered eating, weight cycling, and other health issues. So, I'm not sure where a statement such as "it is not okay to be overweight" really gets us, given that being overweight doesn't seem so simple to change long-term. In addition, this type of message perpetuates stigma, judgement, and negative body image. All things that have been found to lead to (gasp) weight gain. So saying "it's not okay to be overweight" kind of gets us in a pickle, right? I believe that it would be more productive to focus on helping people of all shapes and sizes improve their health regardless of weight loss, rather than telling groups of people that they are "not okay."
The bottom line: don’t judge a research study by its headline. It is often simply not accurate.