It’s common knowledge that being fat increases your chances for heart disease, high blood pressure and chronic joint paint. However, a new study from the Centers for Disease Control and Prevention shows that story to be a little more complex, and having some extra weight on the body may actually help some people live longer.
Researchers examined nearly 100 studies of more than 2.9 million people and 270,000 deaths. Being overweight is defined as having a body mass index (BMI) between 25 and 30, and people with a BMI of 30 or more are considered obese. The researchers found that people who were only “moderately obese”– people with a BMI of 30-35– had a 5% lower risk of death than those of normal weight. Those who were “merely overweight” had a 6% lower risk.
But before you make a quick trip to the kitchen, know that the study also found that the mortality risk was much higher for those with BMI of 35 or above. So those people who are above the minimum obese ranking had a 29% higher risk of death compared to people of normal weight.
As The Economist points out, these findings “add new fuel to the debate over what is called the obesity paradox. Those with chronic diseases such as diabetes and heart conditions seem to show an inverse relationship between BMI and mortality—that is, being moderately overweight seems to have a protective effect.”
The reasons for this aren’t entirely clear. One theory is that moderately obese people tend to suffer from diabetes and other related health issues, and this causes them to see the doctor more often. So the sicker you are, the more care you get, and the longer you live. It may not be a comfortable life, but you’re still living longer.
However, the study also reinforces the belief that BMI is a poor indicator of one’s health. It doesn’t account for sex, age, muscle mass or the distribution of fat in the body. This last point is important; while fat around major organs is bad for your long term health, fat in the legs and gut can actually help reduce some diseases.
The upshot? Waist circumference, blood evaluations, and family history may be just as important as BMI when it comes to assessing health risks. As Men’s Health advises, eat a healthy diet, exercise regularly, and visit your doctor as soon as you think something might be wrong.