It goes by many cute nicknames: beer belly, spare tire, bowlful of jelly. It can make bending over difficult and buying bathing suits excruciating. Sometimes, it can cause confusion, such as the “how many months along are you?” transgression. But no matter what we call it, carrying a few, or many, extra pounds around the abdominal section is not just a cosmetic issue; it’s a threat to health.
All Fat Is Not Created Equal
While it may seem like fat is fat no matter where we find it in the body, different locations do matter. Fat accumulation in the hips and thighs—a characteristic of the so-called pear shape—is usually subcutaneous, while fat collected around the midsection—the apple shape—is visceral. Subcutaneous is the pinchable fat right below the skin surface; visceral fat is located much deeper, closer to our organs.
Generalized excess weight can increase health risks, but weight gain in the midsection—the visceral fat—seems particularly bad. It has been linked to insulin resistance, a precursor for type 2 diabetes, dementia, and an increased risk for cardiovascular disease. In postmenopausal women, it has also been associated with breast cancer.
A 2008 article in Circulation reported that even normal weight women who had an elevated waist circumference significantly increased their risk of cardiovascular mortality. These types of results have led some obesity researchers to advocate waistline measurements—circumference or waist to hip ratio—rather than the standard body mass index (BMI) as the best way to asses a person’s health risks.
Stomach Aches
The tendency to put on weight in the stomach or in the lower body is due to a variety of factors. One is hereditary; women who are pear-shaped usually have a pear-shaped mom; the same goes for apples. Another is gender; men are more likely than women to put on weight in their midsection. Because of gender differences, experts think that sex hormones may play a role. When women go through menopause, for instance, their male hormone levels increase, while female hormones such as estrogen decrease. This may account for the abdominal postmenopausal weight gain. Low activity level can also contribute to abdominal fat.
Stress hormones have also been associated with a heftier middle section. When under stress, our bodies release cortisol, a hormone that can promote fat accumulation in the abdomen. A study published in 2008 analyzed the stress response of sixty-seven women aged eighteen to twenty-five years and found that those women who were most stressed by moderately challenging tasks were more abdominally obese than women with smaller stress responses. Similar studies have shown that even in lean women, higher levels of stress hormones and increased sensitivity to them result in abdominal fat accumulation, compared with lean women with normal levels of stress hormones.
However, cortisol itself won’t lead to abdominal weight gain; it has to be coupled with eating. A laboratory study of mice and monkeys showed that repeated stress, combined with a high fat, high sugar diet (which the American diet is characterized by) releases a hormone called neuropeptide Y that contributes to an accumulation of abdominal fat. However, rodents exposed to stress that ate a normal diet did not accumulate more fat.
More Than Just Hanging Around
Researchers have also found that fat cells, especially the visceral type, aren’t just sitting there—they are metabolically active, behaving more like an endocrine gland than a storage house. The overall effect is not completely understood, but it is known that excess visceral fat can disrupt normal hormonal functioning. It can alter appetite and glucose regulating hormones like leptin and insulin, and fat cells can produce estrogen. Visceral fat also produces immune chemicals that can create low-level inflammation and may contribute to risk of cardiovascular disease. Its location, near internal organs, may also play a role in its harmful effects.
Happy Apples
So, now that stomach fat has been sufficiently vilified, what to do about it?
