The message that obesity is unhealthy is drilled into our heads. We see reports on the news, watch shows like The Biggest Loser, scrutinize celebrities as they struggle with gains and losses, and the resounding message is this: “Drop the weight. Being fat is no good."
But what if it’s not that simple? What if obese isn’t a catch-all equal to “unhealthy?"
In fact, recent research sheds light on a subgroup of obesity, called metabolically healthy obesity (MHO), in which obese individuals do not show an increased risk for negative health issues often associated with obesity, such as metabolic syndrome or cardiovascular disease. Metabolically healthy obesity: definitions, determinants and clinical implications. Phillips CM. Reviews in endocrine & metabolic disorders, 2014, Apr.;14(3):1573-2606. As researchers work to better understand MHO, one thing is clear: Obesity is a nuanced condition with a diverse set of possible outcomes.
MHO is generally described as an obesity phenotype: physical characteristics in a person that result from interactions between environment, lifestyle, and genetics. Metabolically healthy obesity: definitions, determinants and clinical implications. Phillips CM. Reviews in endocrine & metabolic disorders, 2014, Apr.;14(3):1573-2606. But researchers aren't in agreement over the exact definition, which makes MHO complicated to study. One study using body mass index (BMI) found the prevalence of MHO in obese individuals ranged from six to 36 percent (depending on how you define it).
Age and body-fat distribution may play a role in determining who is more likely to be metabolically healthy: One study found that sustained metabolic health in obese individuals was more likely to happen to those under 40 and those whose fat was not on the waist. Diabetes and cardiovascular disease outcomes in the metabolically healthy obese phenotype: a cohort study. Appleton SL, Seaborn CJ, Visvanathan R. Diabetes care, 2013, Mar.;36(8):1935-5548. In contrast, excess fat around the abdomen can contribute to metabolic syndrome, a collection of risk factors that increases the likelihood for diabetes, stroke, and heart disease.
It may be that the amount of fat on an individual’s body matters less than the type of fat and how it’s distributed.
Aaron Mauck, Ph.D., a health services researcher specializing in diabetes and cardiovascular disease, affirms that body shape and fat distribution can play a role in determining the health consequences of obesity.
“Apple-shaped figures, characteristically a male phenomenon, are associated with metabolic syndrome,” Mauck says. He points out that obese women are still at risk for health complications from obesity but are less prone to metabolic syndrome, even at a higher level of obesity. “If you carry [excess weight] in your hips, legs, or breast tissue, that does seem to be a healthier—or safer—obesity.”
In other words, when it comes to determining long-term health outcomes, how fat is distributed on your body matters.
Still, several studies suggest that individuals with MHO, regardless of their current health, are more at risk for long-term negative outcomes (like metabolic syndrome) compared to “normal-weight,” metabolically healthy individuals. Metabolically healthy obese individuals: Key protective factors. Gonçalves CG, Glade MJ, Meguid MM. Nutrition (Burbank, Los Angeles County, Calif.), 2015, Aug.;32(1):1873-1244. Are metabolically healthy overweight and obesity benign conditions?: A systematic review and meta-analysis. Kramer CK, Zinman B, Retnakaran R. Annals of internal medicine, 2014, Jan.;159(11):1539-3704. Prevalence of metabolically healthy obesity and its impacts on incidences of hypertension, diabetes and the metabolic syndrome in Taiwan. Hwang LC, Bai CH, Sun CA. Asia Pacific journal of clinical nutrition, 2012, May.;21(2):0964-7058. One recent study went so far as to say that a "benign obese phenotype" may exist with a strict definition, but currently, "insufficient studies exist to support this." Metabolically healthy obesity and cardiovascular events: A systematic review and meta-analysis. Eckel N, Meidtner K, Kalle-Uhlmann T. European journal of preventive cardiology, 2015, Dec.;():2047-4881.
What It Means for You
Metabolically healthy obesity may exist, but that doesn’t mean the lack of immediate risk for cardiovascular disease or type 2 diabetes equates to a clean bill of health—in much the same way that being "skinny" doesn’t guarantee a person has no risk of developing health issues. The important thing is that all of us—regardless of our weight—should take efforts to protect our health now and later.
Eating well and maintaining an active lifestyle are important for everyone looking to promote long-term health.
“Some aspects of health we have no control over—[the aspects] related to genetics and luck. But the important thing is that there is so much we can control,” says James Hardeman, M.D., a practicing physician for 30 years. “Everyone, including those who are overweight, should be vigilant in detecting the “Big 3": hypertension, hypercholesterolemia [high cholesterol], and diabetes. And you have to do something about them if present,” Hardeman says. That 'do something' means consulting a doctor and making lifestyle changes.
Obesity is a complex topic—and lumping people into one category does nothing to help the average person or medical professionals understand the experiences, needs, and health factors involved. Even if the concept of “healthy obesity” is still being explored, taking steps to eat well and maintain an active lifestyle is important for everyone looking to promote long-term health.
Originally published June 2014. Updated January 2016.