It's the Fat You Can't See That You Should Be Most Worried About — 2 Doctors Explain

There's fat that you can pinch (though you should not make a habit of it) and there's fat that you can't see. That's just one of the distinctions between subcutaneous fat and visceral fat — because, yes, they're different. POPSUGAR spoke to Scott Kahan, MD, MPH, director of the National Center For Weight and Wellness, and Eduardo Grunvald, MD, FACP, medical director of the UC San Diego Weight Management Program, who broke down what sets these two apart and which to be most concerned about.

What's the Difference Between Visceral and Subcutaneous Fat?

The most basic difference between the two, Dr. Kahan said, is where they're located in the body. Subcutaneous fat is the layer of fat under your skin between that and your muscles (hence, pinchable). Some people use visceral fat to describe belly fat, but it's not that simple. It's located around your organs within the abdominal cavity including the heart, pancreas, liver, and stomach. It causes protrusion of the abdomen, Dr. Grunvald said. Fat that is found inside the organs is called ectopic fat and it interferes with the functioning of those organs, Dr. Kahan noted. For example, a fatty liver can lead to steatohepatitis, a type of hepatitis that causes liver inflammation, and it can also increase your risk for diabetes.

Visceral fat is more concerning for your health than subcutaneous fat. "Visceral fat is considered metabolically active, meaning it doesn't just sit there and store fat, but it makes hormones and it responds to hormones," Dr. Kahan explained. "And it can have a very significant effect on a number of weight-related health problems." These include cardiometabolic conditions like high blood pressure, high cholesterol, metabolic syndrome, and diabetes and prediabetes. Sleep apnea and, in severe cases, early heart disease are also things that need to be carefully looked at in relation to visceral fat, he said.

How Do You Know How Much Visceral and Subcutaneous Fat You Have?

The amount of visceral and subcutaneous fat you have depends largely on your genetics, so know your family history. Some people have similar amounts of both — either a lot or a little — while others have more subcutaneous than visceral or vice versa. Dr. Grunvald said it really depends on how functional your fat cells are. Functional cells do their job and store fat on the subcutaneous level, he said. "If you're prone to visceral fat, that means that your fat cells that are normally under the skin, the subcutaneous fat, don't work as well. They grow as they store fat, but at some point they get too stressed," he explained. "And if you're having a positive calorie balance, that fat has to go somewhere." That's when fat starts getting deposited around the organs (visceral fat) and inside of them (ectopic fat).

Dr. Kahan specified that too much visceral fat is not normal, but you can find out exactly how much of it you have through radiology tests like CT scans. Elevated blood sugar, high blood pressure, and other lab results will also indicate you're having problems with visceral fat, Dr. Grunvald said. The easiest way to tell physically is by checking your waist circumference, which you can find guidelines for on the CDC website (and you can ask your doctor about as well). Dr. Kahan used the example of the apple versus pear body type. If you tend to store more fat in your midsection, similar to an apple shape, that's an indication of visceral fat. If you store more fat in your lower body like a pear, you have more subcutaneous.

Dr. Grunvald did note, though, that there are some rare cases called lipodystrophy, where a person is born with a defect that denies them the ability to store any subcutaneous fat. "They have no fat and they're very skinny, but all of their fat is inside the organs, and they're sick because that's not a normal place for it," he said. Conversely, he'll have patients who are 200 pounds overweight and have normal labs because, metabolically, they're "normal" — they store fat subcutaneously and don't have high amounts of visceral fat. Just a reminder that appearance isn't always an indication of one's internal health.

How to Lose Both Visceral and Subcutaneous Fat

When you lose weight, you tend to lose both subcutaneous and visceral fat, and when you gain weight, you tend to gain both — plus, depending on your genetics and your physiology, some people will gain or lose more of one as opposed to the other, Dr. Kahan said. You lose visceral fat first because of the fact that it's more metabolically active. Because of that, both doctors agreed that it doesn't take a lot of weight loss to see improvements in cholesterol, blood pressure, etc. "You need about five percent weight loss to really make significant improvements in all these metabolic problems," Dr. Grunvald noted.

The same lifestyle changes you'd make to lose subcutaneous fat you'll want to make to lose visceral fat. It's not just about eating less; it's about changing the quality of your diet, Dr. Grunvald said. "Eating more fruits and vegetables, more lean protein, less processed food." In terms of working out, he noted what we've written about many times, which is that high-intensity interval training (HIIT) in particular is said to be the most effective for targeting visceral fat. More fat-loss basics include weightlifting, getting enough sleep, and limiting stress. But, of course, talk to your doctor for the right plan for you.

A Note on Monitoring Visceral Fat

Though medical professionals will take your labs during annual visits, Dr. Kahan said, "If you think you have high blood pressure or high blood sugar, certainly seeing a doctor is important. If you already know that you have diabetes or prediabetes, let alone heart disease, that's something to make sure that you stay on top of." Get checked out regularly to monitor progress and take care of your health.