Why is belly (visceral) fat considered more dangerous than other fat?

Not all body fat is the same, and the difference between subcutaneous and visceral fat is real. In the Framingham Heart Study the abdomen was measured with CT in just over 3,000 people free of heart disease. Both subcutaneous and visceral fat were linked to blood pressure, blood sugar, triglycerides and metabolic syndrome, but visceral fat was consistently more strongly tied to an unfavourable profile. The association held even after adjusting for BMI and waist circumference, which suggests this particular depot carries something of its own rather than just reflecting how much a person weighs.

Why would location matter? Visceral fat is more metabolically active and drains in part straight into the portal vein leading to the liver, along with free fatty acids and inflammatory signals. That offers a mechanistic reason why fat on the inside seems to disturb metabolism more than fat under the skin on the hips and thighs, which appears more neutral or even protective.

A joint position statement from the International Atherosclerosis Society, built on roughly 30 years of epidemiology, describes visceral fat as an independent risk marker for cardiovascular and metabolic disease. The word marker is deliberate. You cannot randomise where fat sits, so cause cannot be proven the way it is in a drug trial. Visceral fat may partly be a sign that fat has started to store where it does not belong, such as in the liver and around the heart. The conclusion is not that a large belly is a verdict in itself, but that where the body stores fat says something beyond what the scale shows.

That fat around the organs is the worst kind is broadly true, but the message tends to get flattened into fear and made sellable. A visible belly is easy to judge morally, and fear sells products: belly-fat burners, waist trainers and detox teas live off the worry without being able to direct fat loss where they promise. The nuances drop out at the same time. Where you store fat is shaped heavily by genes, sex and age, you cannot spot-train a belly away, and a risk marker is not the same as a proven cause. A single, obvious villain fat is easier to market than the truth that distribution reflects the whole of metabolism.

You don't choose where fat sits and can't spot-burn the belly, but visceral fat responds to the same things as any other fat: an energy deficit, more everyday movement and better sleep. When you lose weight, visceral fat also tends to give way relatively early. Waist circumference is a cheap, decent measure to track over time, better than chasing belly-specific products. Treat a large belly as a signal to look at the whole picture, not as something to be ashamed of.