It’s one of the dominating controversies in the health world: Can you really be “fat but fit?” Now, a new study in the European Heart Journal provides evidence that carrying too much extra weight can hurt your heart—even if your other risk factors for it are pretty low.
In the study, researchers analyzed health and body mass index (BMI) data from over 520,000 people, and followed up after 12 years to see how many developed heart disease. They determined that overweight and obese people who were considered metabolically unhealthy—meaning they had three or more risk factors like high blood pressure, high triglycerides, low “good” cholesterol, high blood sugar, or high waist circumference—had more than double the chances of getting heart disease than normal-weight people without those factors.
In itself, this isn't terribly surprising. What was surprising, however, is that people who were overweight or obese were still at increased risk of heart disease—even if they didn’t meet that risk-factor criteria.
In fact, metabolically healthy people who were overweight (a BMI between 25 and 30) were 26 percent more likely to develop heart disease than their metabolically-healthy, normal weight peers (a BMI between 18.5 to 25). And those who were obese—a BMI above 30—were 28 percent more likely to develop heart troubles.
That’s not to say there's no benefit to keeping your heart risk factors in check, even if you still have some weight to lose. In fact, the study authors classify the “fat but fit” group at intermediate heart risk—above that of fit, normal weight people, but below that of metabolically-unhealthy overweight or obese people.
Still, the “fat but fit” theory remains controversial, and other studies on it have been mixed. Back in 2013, a study of 4,000 adults in Diabetes Care found that metabolically healthy obese people were no more likely to have a heart attack or stroke over a five to 10-year follow up than normal weight healthy people were.
But over the course of the study, one-third of them developed factors that plunked them right in the “metabolically unhealthy” group.
And that might be the important factor: Even though some overweight or obese people can be metabolically healthy now, they might be less likely to stay that way.
“Our study shows that people with excess weight who might be classed as ‘healthy’ haven’t yet developed an unhealthy metabolic profile,”Ioanna Tzoulaki, Ph.D., author of the European Heart Journal study said in a statement. “That comes later in the timeline, then they have an event, such as a heart attack.”
So your best bet is still to get yourself down to a healthy weight — and you might not need to drop as many pounds as you think.
Even losing as little as 5 percent of your body weight—that’s 10 pounds for an overweight 200-pound guy—can help keep your blood sugar, blood pressure, and triglycerides in check, as we reported in the past.