Visceral fat is metabolically active and inflammatory.  it is also a marker for a far more sinister process. 

As we gain weight insulin resistance increases and it becomes increasingly difficult for the body to store fat that is circulating in the blood in the normal way, in the fat cells just under our skin.

This increases the amount of fat circulating in the blood as triglycerides.  Since the body cannot easily store the fat in the blood as normal fat, it finds other places to store it.  Much of it is stored  in the abdominal cavity as visceral fat but what is even worse is that some of the fat is stored in places where fat should never be, the pancreas, muscles (think wagu beef) and liver.  This is called ectopic fat.  

Both visceral and ectopic fat are inflammatory Which is analogous to rust in a car.  

The rust starts as a small patch which ieft untreated expands and overtime eats into the fabric of the car, eventually leading to holes in the chassis and collapse of the suspension.  Resulting in the early demise of the car.

Similarly insulin resistance is an insidious process that silently undermines our health until its effects emerge as heart disease or diabetes.  

Small amounts are not a big issue but as our waist lines increase so does the amount of the visceral and ectopic fat.  It is widely accepted that keeping our waist measurement to less than 1/2 our height is safe.  As our waist lines expand beyond this marker, the proportion of fat stored in these forbidden locations increases and over time leads to heart disease, diabetes, non alcoholic fatty liver, pancreatitis, dementia and in many cases a slow decline into an early death.