New research suggests that people who have more body fat may have a higher risk of dying early than people whose bodies have less fat. The study also revealed that having a high body-mass index (BMI), a measure often used to gauge obesity, was not associated with early death.
The findings support the idea held by many experts that BMI is a fairly crude measure that may not reflect a person's body composition, or be a good indicator of health. Doctors say it is more important to be aware of what you are made up of, rather than just how much you weigh.
The findings may offer one explanation for the so-called ‘obesity paradox’, where overweight and moderately obese people with heart disease or other chronic ills tend to outlive thinner people with those same conditions.
For their study, researchers at the University of Manitoba in Canada combed through data on more than 54,000 adults, mostly in their 60s, who had undergone DXA scans to measure their bone density. Those bone scans have the bonus of allowing an estimate of a person's body fat percentage.
The study showed that men and women with the greatest amounts of body fat were more likely to die over the next four to seven years. Men in the top 20 percent had at least 36 percent body fat. And those with highest body fat were up to 59 percent more likely to die during the study period, versus men whose body fat was in the 28 percent to 32 percent range.
In contrast, people with a BMI high enough to land them in the ‘obese’ category did not show an increased death risk. And they were actually less likely to die than men and women with the lowest BMIs — lower than 24 or 25, which includes people in the ‘normal’ weight range.
And it is not only about body fat. Fitness levels matter, too: Studies have found that people who stay fit through exercise typically, even though they may be overweight, enjoy a longer life than couch potatoes. Clearly, healthy eating and regular exercise are more important than being thin but out-of-shape.
Taking a tape measure to your waistline, for example, is a simpler way to estimate how much fat you are carrying.
Women who have a waist circumference of more than 90 cm have a higher risk for heart disease and type 2 diabetes, according to medical experts. For men, a waist circumference greater than 100 cm indicates an increased risk of health problems, they add.