New findings published online by the Journal of the American Medical Association suggest that being slightly overweight may be advantageous to your health. In addition, being very overweight — but not obese — poses no additional health threat compared to being a normal weight.
People considered obese — with a Body Mass Index (BMI) of 35 or more — were at a 29 percent greater risk of death during the period of the data analyzed. This correlates with many commonly held assumptions about the relationship between excess pounds and negative health risks.
Yet, researchers also found that, “people classified as overweight, with a BMI of 25 to 29.9, died at slightly lower rates — not higher — than those of so-called normal weight,” reports the Los Angeles Times. “And they found that those who were mildly obese, with a BMI of 30 to 34.9, died in no greater numbers than did their normal-weight peers.”
Only the BMI threshold of 35 indicated potential peril.
Lead researcher Katherine M. Flegal of the Centers for Disease Control, which conducted the analysis, stated that it is unclear why being slightly overweight appears to provide a protective edge. Experts theorized that overweight people might receive more aggressive treatment for heart disease as opposed to thinner patients among several reasons. Fat is also known to provide extra reserves of energy for patients struggling with a severe illness.
Others stressed that these facts should not become an excuse for excessive weight gain.
“That would be a mistake—and this study did show an increase in mortality for people who are obese,” Thomas Frieden, director of the U.S. Centers for Disease Control and Prevention, told The Wall Street Journal. “I don’t think anyone would disagree with the basic fact that being more physically active and eating a healthier diet is very important for your health.”
For some, this revelation is a greater indicator of the flaws of the BMI system, which is based on ratios of weight to height. BMI does not take into account natural variations in muscle mass versus fat mass per individual, or individual distributions of fat on the body. These might be greater indicators of potential health risks.
In fact, the BMI itself is somewhat controversial as a health-assessment tool today. Documentary filmmaker Darryl Roberts tracked the history of the BMI in his film, America the Beautiful 2: The Thin Commandments, revealing that some aspects of the measurement system are arbitrary and not necessarily accurate indicators of health. Slate.com has also reported that the “BMI’s imprecision and publicity-friendly cutoffs may distort even the large epidemiological studies,” such as this recent report by the Centers for Disease Control.
Sources such as these contend that the BMI was never intended as an individual diagnostic tool, and that better methods are available, such as waist measurement, which determines an individual’s level of belly fat, the most dangerous form.
For African-Americans, who often have a higher muscle-to-fat ratio than members of other groups, BMI readings can be particularly misleading. A 2009 study demonstrated the possibility that “body mass index” tests “overestimate obesity in African-Americans,” according to Science Daily. The suggestion was made that “conventional methods for estimating body fat may need to become race-specific.”
Still, these reports should not give blacks license to eat unhealthy foods and forgo exercise. Another health expert told the Journal that everyone should remain focused on good nutrition and remaining active, rather than being a specific weight.
“You’d hate to have the message get out there that it’s good to be overweight,” Mercedes Carnethon, epidemiologist at Northwestern University’s Feinberg School of Medicine, told the paper. “The reality is that people who are overweight very often become obese and that’s clearly not good.”
According to the U.S. Department of Health and Human Services Office of Minority Health, which sets the obesity threshold at a BMI of 30, 38 percent of black men and 54 percent of black women over 20 were obese in 2010. Obesity poses several major health risks, including greater rates of diabetes and heart disease.
Follow Alexis Garrett Stodghill on Twitter at @lexisb.