The study followed a group of British government workers ranging from 39 to 62 years of age over the course of 20 years and recorded changes in their health at 5-year intervals. At the start of the study, 66 participants were labeled as “healthy obese adults,” or having a BMI greater than 30 with normal metabolic levels (cholesterol, blood pressure, and blood sugar). After 20 years, about half had progressed to unhealthy metabolic levels—even without any changes in weight. Time is the major factor, says lead study author Joshua Bell, a doctoral candidate at University College London’s Department of Epidemiology and Public Health. Previous studies proclaiming that it’s possible to carry extra weight but be totally healthy have only viewed overweight or obese individuals at one point in time, recording their blood pressure, cholesterol, and blood sugar levels at that moment. But currently being healthy doesn’t guarantee wellness down the road. “By following healthy obese adults over two decades, we now see that this label of ‘fit but fat’ is misleading, as healthy obese adults tend to become unhealthy obese in the long-term,” says Bell. MORE: Fat 101: The Good, The Bad, The Complicated It’s hard to remain healthy and fat, Bell explains, because excess fat is biologically active, messing with hormone balance and pumping out inflammatory chemicals, which can cause insulin resistance (a precursor to diabetes), cancer, and a lot of other bad things in between. Where you’re stashing that extra weight also makes a difference. Study subjects who were “fat but fit” at the outset and had favorable fat distribution (basically anywhere other than around the abdomen) were better able to maintain their healthy obesity status—but only slightly. And while those who maintain a slender frame aren’t exempt from metabolic issues, adults with a normal BMI (18.5-24.9) are far less likely to become diabetic—only 24% of normal-weight adults in this study were found to have unhealthy metabolic levels (which could indicate diabetes), while an overwhelming 70% of obese adults were considered unhealthy by the same measures. MORE: This Food Can Help You Shed Up To 7 Pounds Of Belly Fat
