In a report published this week, researchers showed that the waistlines of Americans are still expanding. This is bad news, since excess fat, especially around the waist, has serious implications for our health. Fortunately, there is much we can do to lose weight and improve our health.
The study, published in the Journal of the American Medical Association, looked at the percentage of adults who had a high waist circumference (over 35 inches for women and over 40 inches for men). Overall, the average American added over one inch to their waist circumference over the past decade. As of 2012, over half of U.S. adults (51%) meet the criteria for abdominal obesity, compared to 46% in 2000.
Since excess muscle tends to compress the abdomen, this really does reflect an increase in fat around the waist, not the benefits of a national sit-up campaign. And it is the location of the fat that makes this worrisome. Excess fat around the waist includes both subcutaneous fat beneath the skin (what you can pinch) as well as visceral fat stored deep in the abdomen.
Excess visceral fat is associated with an increased risk of high blood pressure, type 2 diabetes, and heart disease, among other chronic conditions. The only way to determine how much visceral fat a person has is through an imaging test like a CT scan. (In my lab we can estimate visceral fat by making a few abdominal measurements.) The important point is that the bigger your waist circumference, the more visceral fat you likely have.
You may have heard of people’s body shapes described as “apple” or “pear.” Upper body obesity (apple), sometimes called android obesity because it is more common among men, is associated with a high waist circumference and visceral fat. Lower body, or gynoid, obesity (pear shape) tends to involve a narrower waist but more fat storage in the hips, thighs, and buttocks.
These body shapes become apparent when you measure both waist and hip circumferences. A high ratio between waist and hip measurements indicates more upper body fat; a low waist-to-hip ratio suggests lower body fat. That said, just measuring your waist circumference can give you the same information. A waist measurement greater than 40 inches for men and 35 inches for women indicates excess upper body—and visceral—fat.
There is no single explanation for why waist circumference has increased so much in the population. But it almost certainly has to do with a combination of individual factors including what foods we eat, how much we eat, and how active we are. The average American with an expanding waistline likely eats too much poor quality food and doesn’t get enough exercise.
These are exactly the same factors that, when reversed, can lead to fat loss. Indeed, research shows that even modest weight loss from a low-calorie diet and exercise can result in reduced body fat, including visceral fat. This is one reason why weight loss is effective for reducing high blood pressure and controlling blood glucose.
Even if you don’t lose weight, increasing your level of physical activity, particularly regular exercise, can offset some of the negative health effects of excess visceral fat. In addition to helping you lose weight, exercise can also help you maintain your waistline and prevent abdominal obesity.
The bottom line is that when your pants start to feel tight, they are trying to tell you something. Listen to them!