Is some extra weight good for you?

Authored by Michael A Dedekian, MD

Scale With Question MarksA recent study in the Journal of The American Medical Association (JAMA) caught the attention of national media. The authors used the best available scientific evidence, combined from 97 other separate studies, to better define the link between mortality (death) and weight. The evidence they used represented a total sample size of close to 3 million people. One of their results was surprising: individuals who had a smaller number of extra pounds (termed “overweight”) seemed to have lower mortality compared to those with a lower weight (more healthy) weight. Individuals who had a very high number of extra pounds had worse outcomes and higher mortality, consistent with prevailing science, and prevailing wisdom.

“Overweight” is defined medically as having a body mass index (BMI, a calculation using height and weight) between 25 and 30. For a 5 foot 10 inch tall man this would correspond to a weight around 200 pounds. For a 5 foot 6 inch tall woman this would be around 175 pounds.

Could a small amount of extra weight actually promote better health? The answer is not clear. The authors of the JAMA study point out that their results hinge on the calculation of BMI itself. While an important tool for health care providers and scientists studying populations, BMI for any given individual should be used cautiously. It does not accurately take into account the balance of fat and muscle in the body, nor does it reflect behaviors like healthy eating or exercise. Further, the study only looked at lifespan, not quality of life or other complicating factors that may have been present. For example, as one JAMA commentator pointed out, it is possible overweight patients were provided more health care, or were taking more medicines, which might account for some of the reported results.

This study, which only included adults, does not establish that a small amount of extra weight is healthy but it does highlight that our approach to health should be broad. BMI is an important tool for doctors and nurses to help find the best paths to health for their patients but it has important limitations. As I tell all my patients, healthy habits, which 5-2-1-0 reminds us about, are always more important to focus on than a specific number of pounds or BMI.

This blog post is brought to you by Let’s Go! Healthcare, generously funded by Harvard Pilgrim Foundation’s Growing up Healthy Initiative.


Dr. Dedekian is Medical Advisor to Let’s Go! and Director of Countdown to A Healthy ME Clinic.