Harvard Heart Letter

Stay lean, live longer

For the past few years, the "obesity paradox" has been getting a lot of attention. It began when several studies suggested that people who packed on the pounds with age lived longer than those who stayed thin. But the research didn't properly account for factors such as cigarette smoking or an underlying serious illness that can trigger weight loss and contribute to an early demise.

An analysis of studies that followed 1.5 million Americans over time may finally resolve the issue (New England Journal of Medicine, Dec. 2, 2010). After excluding smokers and people with underlying illnesses, the researchers found that the death rate across various age categories was lowest for people whose body mass index (BMI*) was in the normal range (20 to 24.9), and then increased steadily with BMI. People who were morbidly obese (a BMI of 40 or greater) were 2.5 times more likely to have died during the study period than those who maintained a normal weight. Of interest to Heart Letter readers, cardiovascular disease was the most common cause of death among people who were overweight or obese.

The study wasn't perfect. It was based on white Americans, so the results may not apply to African Americans, Hispanics, or other ethnic groups. Still, at a time when 68% of Americans are overweight or obese, this study provides a reminder that it's important to keep your weight within the healthy range, or work to move it in that direction, to protect your heart and live longer.

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