New York: If you have developed a spare tyre, it is time you saw a doctor to assess your cardiovascular health as researchers have found that belly fat, even in people who are not otherwise overweight, is bad for the heart. "People with a normal weight but a fat belly have more chance of heart problems than people without a fat belly, even if they are obese according to BMI (body mass index)," said study author Jose Medina-Inojosa from the Mayo Clinic in Minnesota, US.