The good news is that the rising tide of obesity in the U.S. may have peaked; the bad news is our waistlines haven't gotten the message. Even as weight gain among Americans has slowed, average waist circumference has grown, a bad sign.
Some researchers support the idea of waist circumference being added to the list of measurements your physician already takes. That's because fat deposited around your midsection, as opposed to in your hips and thighs, is far more damaging to your health.
When data from the last few National Health and Nutrition Examination Surveys (NHANES) showed that obesity, based on body mass index (BMI), had stayed about the same for the past several surveys, health experts were hopeful that the decades-long rise in obesity had finally reached its peak.
Waist circumference increased from 37.6 inches in the 1999-2000 survey to 38.8 inches in 2011-2012.
A team from the Centers for Disease Control and Prevention looked at seven cycles of NHANES data on nearly 33,000 men and non-pregnant women ages 20 years and older. Waist circumference increased from 37.6 inches in the 1999-2000 survey to 38.8 inches in 2011-2012.
Mexican Americans showed the greatest increase (1.8 inch) followed by non-Hispanic blacks (1.6 inch), non-Hispanic whites (1.2 inch), women (1.5 inch), and men (0.8 inch).
The overall prevalence of abdominal obesity increased from 46.4 percent to 54.2 percent between the seven NHANES cycles. The greatest increases were seen in women and Mexican Americans.
“The reasons for increases in waist circumference in excess of what would be expected from changes in BMI remain speculative, but several factors, including sleep deprivation, endocrine disruptors, and certain medications, have been proposed as potential explanations,” the authors write.
Waist circumference is an independent predictor of health risk over and above BMI. Excess fat in the abdominal area is a combination of subcutaneous (beneath the skin) fat and visceral (around the organs) fat. Why belly fat is more of a health risk than excess fat on other parts of the body isn’t entirely clear.
The authors support the idea of adding waist circumference to the list of measurements already used in clinical practice. Doing so, they believe, could help people better understand their own risk for obesity–related health problems, the first step to reducing them.