Visceral fat is fat stored deep inside the abdomen, surrounding organs such as the liver, pancreas, and intestines. This is different from subcutaneous fat, which sits just under the skin and can be pinched.
Compared with subcutaneous fat, visceral fat is more strongly associated with insulin resistance, type 2 diabetes, and cardiovascular disease. That is part of why waist measurement, not just overall weight, is often used to gauge metabolic health.