Julia Belluz flags new research showing that American waistlines are growing:
Researchers looked at waist circumference measurements taken from over 32,000 adults in 1999 and 2012. During that period, participants’ waists grew nearly a whole pants size, from 37.6 inches to 38.8 inches. Some groups gained an even more significant amount of abdominal girth. White women, aged 40 to 49, experienced a 2.6-inch expansion; the waists of black men, aged 30 to 39, got padded with 3.2 extra inches; Mexican-American men, aged 20 to 29, added 3.4 inches to their frames; Mexican-American women over the age of 70 packed on 4.4 inches; and black women between the ages of 30 to 39 increased their waists by 4.6 inches. (Abdominal obesity was defined as a waist circumference greater than 40 inches in men and 35 inches in women.) That racial minorities are experiencing greater gains maps on to the fact that they’re also disproportionately struggling with obesity compared to white people in the US.
Interestingly, Americans’ average body mass index has held relatively steady over the past decade. Or as Alison Bruzek puts it, “People haven’t been getting fatter, but their waistlines are still increasing”:
“We’re a little bit puzzled for explanations,” Dr. Earl Ford, a medical epidemiologist at the Centers for Disease Control and Prevention and lead author of the study, tells Shots. The two measures are closely related: While body mass index or BMI measures fat overall, waist circumference helps measure fat distribution. Stress, hormonal imbalances, environmental pollutants, poor sleep or medications that help pack on abdominal weight are possible causes, health and nutrition researchers speculate. And older adults typically lose muscle as they age, while fat continues to increase.