What is visceral fat and why is it more dangerous than subcutaneous fat?
Visceral fat is more dangerous than subcutaneous fat because it sends inflammatory substances and fatty acids directly to the liver through direct pathways, thereby increasing the risk of cardiovascular disease and diabetes regardless of your weight. Exercise and eating less help, and your waist circumference is a better indicator than the scales alone.
Visceral fat is the fat that accumulates in the abdominal cavity, surrounding organs such as the liver, pancreas and intestines. It differs fundamentally from subcutaneous fat, which sits directly beneath the skin. Subcutaneous fat acts as a kind of buffer: it stores surplus energy in a relatively safe way. Visceral fat does not, and once it is present in excessive amounts it behaves like an active and harmful organ.
The biggest problem is the location of visceral fat. It borders directly on the portal vein, the blood vessel that leads to the liver. As a result, the fatty acids and inflammatory substances that visceral fat produces flow straight into the liver. This disrupts the liver's metabolism, promotes fat accumulation there, and prompts the liver to produce more harmful blood fats. Subcutaneous fat does not have this direct channel to the liver.
Visceral fat also contains more immune cells than subcutaneous fat, and it secretes higher quantities of substances that promote inflammation. This chronic, low-grade inflammation is one of the most important mechanisms behind insulin resistance, high blood pressure, low HDL cholesterol ('good' cholesterol) and high triglycerides. All these factors combined increase the risk of cardiovascular disease and type 2 diabetes, regardless of total body weight. Someone with a normal BMI can therefore still have a dangerously high amount of visceral fat.
When visceral fat becomes chronically overloaded, fat starts ending up in places where it does not belong at all: in the liver cells, the heart muscle, the pancreas and the skeletal muscles. This further disrupts the functioning of those organs. At the same time, the fat cells themselves become damaged and begin to age and show scarring, making the tissue even more dysfunctional.
Good news: visceral fat responds relatively well to lifestyle changes. With weight loss through eating less and moving more, visceral fat decreases faster than subcutaneous fat. Measuring your waist circumference is a more useful indicator for this than BMI alone, because it better reflects how much visceral fat is present. Medications and hormone therapies that can reduce visceral fat also exist, but they sometimes have serious side effects and are not suitable for everyone; discuss this with your doctor.
This answer is based on multiple extensive scientific reviews. It largely concerns summarised research in humans, in which the associations between visceral fat and cardiometabolic risk are robust and have been repeatedly confirmed. Causality is well supported biologically through the portal vein hypothesis, although part of the evidence rests on comparative and mechanistic research. Evidence on the effects of hormonal therapies is thinner and the safety risks are uncertain.
How dangerous is a fatty liver (hepatic steatosis)?
For most people a fatty liver is stable for the time being, but it substantially raises the risk of cardiovascular disease, diabetes and liver disease; losing weight is so far the only proven way to limit the damage.
Does eating more fibre help against high blood sugar?
Eating more water-soluble fibre probably helps in lowering high blood sugar, but the overall meal composition also plays a role. Choose legumes, vegetables and fruit if you want to increase your fibre intake, and watch out for side effects when making a large increase.
Is brown fat really different from regular fat, and can I activate it?
Brown fat is genuinely different from regular fat and you can activate it, with cold exposure having the strongest evidence. Supplements and medications do not yet exist, but spending time in a cooler environment regularly is a concrete, achievable step.
How bad is fructose compared to regular sugar?
Fructose places a greater burden on the liver than glucose and raises triglycerides, belly fat and uric acid more. But regular sugar is already half fructose, so the practical difference is smaller than you might think. The greatest health benefit comes from cutting back on sugar-sweetened drinks, regardless of the type of sugar.
Why do you gain weight more easily after 40, even if you eat the same amount?
After forty, your body burns fewer calories, mainly due to muscle loss and a lower resting metabolism. You therefore do not need to eat more to still gain weight, but eating less or exercising more can partly compensate for this.
What is the relationship between fatty liver and type 2 diabetes?
Fatty liver and type 2 diabetes mutually reinforce each other: they share the same underlying mechanism and roughly double each other's risk. If you have a fatty liver, addressing it is also a way to reduce your risk of diabetes.