The formula for BMI — weight in kilograms divided by the square of height in meters — was invented in the early 19th century as an easy measurement of obesity in the general population and not necessarily for individual fatness, according to NPR.BMI is still used regularly today by medical professionals to determine if a person has a healthy amount of body fat.Though it can be useful in a general sense, BMI misses important factors such as family history, genetics, lifestyle, age, sex, and muscle mass when considering a person's overall health and their risks of developing diseases.In fact, many people who are considered in the normal BMI range were found to be unhealthy based on other factors, a UCLA-led study released in 2016 found.Here are seven signs that you're actually healthy, even if your BMI says you have overweight or obesity.Waist size may actually be one of the most important factors in measuring a person's overall health, Insider previously reported. You may have a high BMI, but if the circumference of your waist is below 35 inches as a woman and 40 inches as a man, you're more likely to have a healthier weight.A waist circumference greater than 35 inches in women and greater than 40 inches in men could not only determine overweight status but put a hard-and-fast number on one's health, dietitian Michelle Routhenstein, MS, RD, CDE, CDN, told Healthline.Waist circumference above these numbers indicates excessive belly fat, a dangerous type of fat surrounding vital organs, which increases one's risk of diabetes, high cholesterol, high blood pressure, and the metabolic syndrome, she added.Similarly, where your body stores fat is an indicator of your health that's missed by BMI. [BMI] also does not tell us the distribution of body fat in a person, Eva Tseng, MD, MPH, an Assistant Professor of Medicine at Johns Hopkins, told PopSugar. We know that people with more central or abdominal adiposity [obesity] have a higher risk of premature cardiovascular disease, diabetes, and death compared to people with a similar BMI but less abdominal adiposity.In other words, fat that builds up around your waist and belly is more dangerous than the fat that gets stored around your thighs and hips.BMI doesn't account for body composition, which means it misses the difference between muscle mass and fat.Because muscles are more dense and heavier than fat, bodybuilders and other professional athletes like football players are often considered obese or overweight based on their BMI alone.Someone who has a high BMI due to muscle mass most likely doesn't need to worry about the health problems associated with obesity and being overweight.Dr. Scott Kahan, the director of the National Center for Weight and Wellness, told WebMD that there are plenty of people who are overweight according to BMI, but still healthy according to other indicators.They're heavy, he said. Their BMI puts them in the obesity range. And yet on every level that we look at, their health is actually quite good. Their cholesterol and blood pressure are excellent. Their blood sugar is excellent. They don't seem to have any health effects associated with their excess weight.This is sometimes called metabolically healthy obesity. Because BMI can't holistically show a person's health, having a doctor test your cholesterol, blood pressure, and blood sugar is a good way to evaluate how your body size is really affecting your health.If you're generally fit and active, you're going to be healthier than someone who isn't, regardless of their BMI.According to a 2007 study done on veterans with type 2 diabetes, a person's level of fitness predicts their mortality better than BMI.It's much more important to avoid low fitness than it is to avoid fatness, cardiologist Carl Lavie MD, FACC, FACP, FCCP told Mother Jones.Dr. Richard Atkinson, a researcher and editor of the International Journal of Obesity, told WebMD that older people who are slightly overweight tend to live longer than leaner elderly people, though the reasons for that are unknown.People who are older probably should have a little more fat on them, [but] they shouldn't have a BMI of 30, he said.Depending on your ethnicity, your BMI could be more or less unhealthy than you think.Studies have shown that Asians have a greater risk of developing type 2 diabetes at a lower BMI and have a higher mortality risk for being overweight at a lower BMI.Conversely, African-Americans may have a higher BMI without the same health risks that a white person might have, according to WebMD. They're also less likely to have fat concentrated in the belly area.