Having even just a small “beer belly” or “muffin top” may be deadly to people who already have coronary artery disease, according to a new study.

Researchers with the Mayo Clinic said people whose fat collects around the belly are more at risk of death than people whose fat collects elsewhere on their bodies. The researchers said in a statement that the effect was true even for patients with normal body mass indexes.

The researchers looked at the medical history of 15,923 people with coronary artery disease who participated in five studies from around the world. They found that participants who were centrally obese – measured by waist circumference and waist-to-hip ratio – had up to twice the risk of dying.

They equated the risk to that of smoking a pack of cigarettes per day or having very high cholesterol, particularly for men.

Lead researcher Dr. Francisco Lopez-Jimenez said that belly fat is called visceral fat, which has been found to be more metabolically active. He said it produces more changes in cholesterol, blood pressure and blood sugar.

Lopez-Jimenez said people whose fat is in places like the legs and buttocks don’t share the same risk.

A full report on the study is published in the May 10 issue of the Journal of the American College of Cardiology.