What does having excess belly fat mean if the rest of your body is at a normal weight? A lot, apparently. If your body mass index (BMI) is normal, but you carry extra weight around your middle—called normal-weight central obesity—you stand a higher chance of premature death than a person who’s overweight or obese but doesn’t have extra belly fat, says a study published in the December 2015 Annals of Internal Medicine.
BMI is based on weight and height measurements but doesn’t take into account waist size or fat and lean mass. A waist circumference of more than 40 inches for men and more than 35 inches for women is typically considered high risk.
Researchers looked at the BMIs and waist-to- hip ratios, or WHRs (another way of measuring central obesity), of more than 15,000 adults ranging in age from 18 to 90. Men with normal BMIs (18.5–24.9) and central obesity were twice as likely to die prematurely than men who were overweight or obese as judged by BMI only. Additionally, their risk of premature death was 87 percent higher than men of normal weight with less belly fat. Women’s survival rates were only slightly better.
Those with normal BMIs and central obesity had a 32 percent higher death risk than overweight or obese women. When compared with women with normal BMIs and WHRs, they had a 50 percent increased death risk.
Past studies have implicated excess abdominal fat with increased rates of cardiovascular disease, type 2 diabetes and high blood pressure. Extensive visceral fat (central obesity) is also associated with metabolic syndrome (a disorder that includes insulin resistance, high blood pressure and abnormal cholesterol and triglyceride levels, which elevates the risk of heart problems)