What are visceral fat and subcutaneous fat?

In one line

Subcutaneous fat is the fat lying just under the skin, and visceral fat is the fat stored between and around the organs inside the belly.

What are visceral fat and subcutaneous fat?
Is all belly fat the same fat?
Body composition scans and health checkup reports often mention 'visceral fat.' Even within belly fat, the fat you can grab and the fat deep inside the belly have different names. So how are the two different?
In one line
Names based on where the fat sits
Subcutaneous fat is the fat lying just under the skin. Visceral fat is the fat stored inside the belly, between and around organs such as the stomach and intestines. Both are stored body fat, and they are named by where they sit.
Where fat is kept
Tissue made of fat cells
Stored body fat sits inside cells called 'fat cells' as droplets of oil. Tissue made of fat cells is especially common under the skin and inside the belly. Subcutaneous fat and visceral fat are names for where this tissue is located.
Subcutaneous fat
The fat under the skin you can pinch
Subcutaneous fat lies just under the skin all over the body: arms, thighs, belly and more. When you pinch the belly or arm between thumb and index finger, the fat you grab along with the skin is subcutaneous fat. It stores nutrients and keeps body heat from escaping.
Visceral fat
Belly fat you cannot grab
Visceral fat builds up inside the belly, in the space that holds the organs. It is mostly attached to the thin sheets that wrap the stomach and intestines and hang them from the belly wall. It cannot be caught by pinching the skin.
Why look at it separately
Visceral fat is closer to disease
People with more visceral fat had a higher risk of heart disease, diabetes and death. This link remained even after taking body weight into account, and visceral fat predicted death better than subcutaneous fat. So experts advise looking at where fat is stored, not just body weight.
What visceral fat is like
It releases fat easily, and its blood goes to the liver
Visceral fat is the most active fat in the body. Breaking down its stored fat and releasing it into the blood happens more easily than in subcutaneous fat. Also, blood that passes through visceral fat flows straight to the liver.
Men and women
Men store it in the belly, women in the hips and thighs
Men store more fat around the belly, especially as visceral fat. Women before menopause have less visceral fat and store more fat in the hips and thighs. Fat gathered around the belly carried a higher risk of diabetes and heart disease than fat stored in the hips and thighs.
How it is measured
CT or MRI for accuracy, waist size for a quick check
The amount of visceral fat is measured accurately with CT or MRI, hospital scans that take pictures of the inside of the body. Without a scan, it is estimated by measuring around the belly just above the hip bones, which is the waist circumference. Still, people with similar waist sizes had very different amounts of visceral fat.
Common misconception
Do thin people not need to worry about visceral fat?
No. Some people with normal body weight had a lot of visceral fat, and researchers named this type 'thin on the outside, fat on the inside.' People with normal body weight whose waist was large compared with their hips had a higher risk of death than people with normal body weight whose waist was not.
Summary
Where fat sits matters as much as how much
Subcutaneous fat lies just under the skin, and visceral fat is stored between and around the organs inside the belly. Some people with normal body weight have a lot of visceral fat, so body weight alone does not show it. Related terms: body fat percentage, BMI (body mass index), brown fat.