Experts Say These Are the Exact Dangers of Belly Fat
Did you know that when medical professionals talk about excess belly fat, they're likely referring to something a lot more critical than having a less-than-flat stomach? What they often mean by belly fat is visceral fat, which is found deep inside our abdomens, surrounding our organs. Having too much of it, which isn't necessarily an obvious thing, has been linked to several serious diseases.
To help break down the unique dangers too much belly fat can present to our overall health, we talked with two experts from the University of North Carolina at Chapel Hill School of Medicine, Dr. M. Sue Kirkman, professor of medicine and medical director of the Diabetes Care Center Clinical Trials Unit in the Division of Endocrinology and Metabolism, and Dr. Sriram Machineni, assistant professor and director of the Medical Weight Clinic. Read on for their expert medical opinions.
How Is Belly Fat Different From Other Types of Fat
"Subcutaneous fat is the fat immediately below the skin and above the muscle layer," Machineni said. It's typically found on the buttocks, thighs or upper arms, and is the type of fat you can sort of see or kind of move around if you touch the skin on top of it. "It's not strongly associated with any health impairments," Machineni said.
"Visceral fat is fat inside the abdominal cavity, surrounding the abdominal organs or viscera," Kirkman added. These organs include the liver, pancreas and intestines. "We used to think that all fat was primarily just storage tissue, and that it didn't otherwise do much. It turns out that subcutaneous fat is primarily just for storage, but visceral fat is much more active. It secretes hormones and inflammatory factors that contribute to insulin resistance, cholesterol/triglyceride abnormalities, and risk of diseases such as type 2 diabetes, heart disease, and cancer."
What Are the Unique Dangers of Excess Visceral Fat
Kirkman told us that diseases associated with excess belly fat include heart attacks and strokes, type 2 diabetes, polycystic ovarian syndrome (PCOS) — which may result in irregular periods, infertility, and excessive facial or body hair growth in women — as well as certain cancers such as colon cancer. Sleep apnea, hypertension, and fatty liver disease (which can progress to cirrhosis) are also linked to high levels of visceral fat.
Arthritis is also more common in people with excess visceral fat, but it may be due to more than just carrying more weight, instead possibly having to do with inflammatory factors that visceral fat secretes. "Depression and even dementia are associated with excess visceral fat, for reasons we don't fully understand, as well," Kirkman said. "Excess visceral fat is connected to a number of other diseases and even with premature death. Whether it's a direct cause, or just linked to these diseases due to shared genetics or shared risk factors, isn't entirely clear."
How Can You Know If You Have Excess Visceral Fat
The simplest way of trying to evaluate the amount of visceral fat in our bodies is by measuring our waist circumference. "This is not the same as the waist measurement on your pants." Kirkman said. "It needs to be done with the tape measure right at the top of your hip bones, and horizontally around the abdomen as you are standing."
"Find your body mass index or BMI, then measure your waist circumference if your BMI is less than 35," Kirkman said. If your BMI is higher than 35, it's most likely a given that you have visceral fat in addition to subcutaneous fat.
Kirkman recommended this approach particularly for people of Asian descent, because it doesn't take much excess visceral fat for them to have increased risk of type 2 diabetes or other medical problems. "A waist circumference of 40 inches or greater in men or 35 inches or greater in women is considered too high. In Asian Americans, those cut-points are 35 inches in men and 31 inches in women."
What's tricky is that someone who looks very much to be in great physical health can still have excess visceral fat. "It's known to occur in athletes who consume large amounts of simple carbohydrates, despite their high level of exercise," Machineni said.
Plus, as our bodies age, the amount of subcutaneous fat reduces and the amount visceral fat increases. "Therefore, even when our overall weight is the same, as we age we have a significant increase in visceral fat," he said. "Waist circumference is not an accurate measurement of visceral fat, but is a reasonable compromise," he added.
What Causes Excess Visceral Fat
"Excess belly fat accumulates for many of the same reasons as excess subcutaneous fat," Kirkman said, citing overeating and lack of exercise. Machineni added that diets that include a lot of processed foods and a high amount of simple carbohydrates, as well as foods that stimulate the secretion of insulin and have been implicated in causing insulin resistance, are thought to increase visceral fat accumulation.
There are also genetic and hormonal contributors. Machineni cited one paper that found 49 different genetic markers said to determine the location where most excess fat accumulates, published in 2015 by the US National Library of Medicine National Institutes of Health.
Estrogen and testosterone levels may also play a role, Kirkman explained. "Before menopause, women tend to accumulate their fat more in the subcutaneous space; after menopause fat tends to accumulate in the belly, so estrogen seems to play a role in body fat distribution in women," Kirkman said. "Testosterone levels appear to help men keep body fat and visceral fat levels lower, but in contrast high testosterone levels in women, as may be experienced by those with PCOS, are associated with more visceral fat."
Kirkman also noted that more rare hormonal conditions, such as Cushing Syndrome, where too much cortisol is produced due to adrenal or pituitary tumors, may also lead to central obesity and too much visceral fat. Genetics and the environment, including the type of diet, amount of exercise, age, and hormonal status all work in conjunction to produce the final result, Machineni said.
What Should We Do to Avoid or Get Rid of Excess Visceral Fat
"The best ways to avoid or get rid of excessive belly fat is to keep exercising, and weight under control through a healthy diet," Kirkman said. "For those who would like to get rid of the fat that has already accumulated on the abdomen, low-carb diets may be more effective, especially when combined with a mix of regular aerobic and resistance exercises," Machineni said.
It's not about just seeing the number in the scale go down, but about reducing the possible health risks of having too much belly fat. "While excess weight affects a person's appearance and has an impact on social interactions and psychology, obesity is a real disease with health implications which go beyond how people look."