Being moderately overweight is associated with the longest life expectancy.
For most of the 20th century, actuaries had shown that life expectancy followed a bell-shaped curve. People who were at their ideal weight or thin or those who were obese had a shorter life expectancy than those who were overweight. In other words, actuaries said if you had a body mass index (BMI) between 24 and 30, you lived the longest.
A few years ago, this concept was debunked when a series of research articles in prestigious journals showed that even a few extra pounds shortened life expectancy.
Now comes a new article in the Journal of the American Medical Association that analyzed the results of 97 studies involving 2.88 million people in whom weight was correlated with life expectancy. In this report, individuals who were overweight having a BMI between 24 and 30 were 6 percent less likely to die from all causes than those who were at their ideal weight and 16 percent less likely to die than those who had a BMI above 35.
While the evidence is compelling that overweight people live longer, they may well not live better. After the age of 60, the combined effect of less muscle and more fat puts overweight individuals at a much greater risk of experiencing weakness, frailty and difficulty walking. This in turn contributes to falls, fractures and loss of physical independence.
Mixing being overweight with a sedentary lifestyle is a prescription for disaster, and it almost always leads to a poor quality of life.
But combine being plump with exercise, and your future can be bright.
In fact, if you are fat, you'd better be fit. All it takes is regular exercise, and a chubby person can remain as physically strong or stronger than any sedentary person, thin or not. Research done at the Cooper Clinic has clearly shown that overweight individuals who exercise are far healthier than sedentary individuals who are thin.
Furthermore, overweight individuals who still exercise have a significantly lower risk of heart disease and stroke than someone who looks to be "in good shape" but doesn't exercise.
I am not suggesting that obesity isn't a problem.
The "obesity epidemic" is real. An analysis from the National Health and Nutrition Examination Survey (2009-2010) showed that 35.7 percent of adults were obese with a BMI of 30 or higher.
A quick review: To accurately assess a person's weight, you have to correct the value for their height. This is done using the body mass index, which is calculated by dividing weight in pounds by height in inches squared then multiplying by 703.