You’re overweight, but you feel fine, you move around, and at the end of your last physical your doctor said all your lab tests were in the normal range, so everything’s A-OK, right? Well, it’s not exactly that simple. New research suggests that even if you feel like you’re perfectly healthy, obesity can be wreaking havoc under the surface.Healthy body weight is much more than the numbers on your scale. In a previous column we looked at BMI (Body Mass Index), an imperfect but useful way to get a sense of whether you’re carrying an unhealthy amount of fat. In a nutshell, the ideal BMI is from 19 to 24. Between 24 and 27 is okay, and between 27 and 29 signifies overweight. A BMI of 30 or above signals obesity.Like any rule, there are exceptions. Some people have a healthy BMI but are actually obese, meaning that they have a high body fat percentage (aka skinny fat). Others, meanwhile, are often called “fit and fat”—heavy but healthy. This latter category has sparked a lot of debate, with some studies showing that active overweight or obese people have a lower risk of death than skinny people who remain sedentary (and of course also lower than skinny smokers), and others showing that no amount of exercise can make up for carrying too much body fat.The latest research shows strong evidence that healthy obesity is impossible. A study released online by the Journal of the American College of Cardiology in May 2014 looking at nearly 15,000 healthy adults found that far more obese participants than normal weight patients had plaque in the arteries that flow to the heart. Though they seem healthy—with no metabolic conditions, such as insulin resistance, that can lead to heart disease—their blood vessels were actually in much worse shape. The calcium build-up in the plaque on their artery walls indicates early stage arterial heart disease long before symptoms are present.All YouBeauty readers surely realize by now that a healthy lifestyle comprises many factors, from what you eat, to how much physical activity you get, to how you handle stress and more. No one factor alone can make you “healthy.” However, one single factor can derail an otherwise balanced life. In this case, the factor in question is obesity, and the damage it can cause cannot be overstated and should not be overlooked, even if it doesn’t feel like it’s hurting you right now. We spend so much time on this topic because obesity is overtaking tobacco as the most costly and most disabling health problem in America, and the most injurious to your vitality and energy levels.No single program works for everybody, but if you or a friend has a problem with weight, you are like more than half of Americans, and you can get help. Keep persisting until you find a plan or program that works for you or your friend.MORE: Find Out Your BMI