Visceral Fat: Why Where You Store Fat Matters More Than How Much You Have

What is visceral fat?

Body fat is stored in two main compartments. Subcutaneous fat sits just beneath the skin and is the fat you can pinch — on the abdomen, thighs, arms, and elsewhere. Visceral fat is stored deeper, within the abdominal cavity, surrounding the liver, pancreas, intestines, and other organs. It is sometimes referred to as active fat because, unlike subcutaneous fat, it is metabolically active in ways that directly affect health.

Why is visceral fat more dangerous than subcutaneous fat?

Visceral fat is not simply an inert energy store. It functions almost like an endocrine organ, secreting a range of biologically active substances including:

• Pro-inflammatory cytokines — including interleukin-6 and tumour necrosis factor-alpha, which drive systemic inflammation and contribute to insulin resistance
• Free fatty acids — released directly into the portal circulation and delivered to the liver, contributing to non-alcoholic fatty liver disease and impaired glucose metabolism
• Adipokines — including reduced levels of adiponectin (a protective hormone) and elevated levels of leptin and resistin, which promote insulin resistance

This metabolic activity makes visceral fat a direct driver of the conditions associated with obesity, rather than simply a marker of excess weight.

What health conditions are linked to visceral fat?

High visceral fat is independently associated with:

• Type 2 diabetes and insulin resistance
• Cardiovascular disease, including heart attack and stroke
• Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH)
• High blood pressure
• Dyslipidaemia (abnormal cholesterol and triglyceride levels)
• Certain cancers, including colorectal and pancreatic cancer
• Obstructive sleep apnoea
• Polycystic ovary syndrome (PCOS)

Importantly, these risks are elevated even in people whose overall BMI is within the normal range — a phenomenon sometimes called metabolically obese, normal weight, or TOFI (thin outside, fat inside).

How is visceral fat measured?

The gold standard for measuring visceral fat is MRI or CT scanning, which can precisely quantify fat in different compartments. These are not routinely used in clinical practice due to cost and radiation exposure. Waist circumference is the most practical clinical proxy — a waist measurement above 94 cm in men or 80 cm in women (lower thresholds apply for South Asian populations) is associated with elevated visceral fat and increased metabolic risk. Waist-to-hip ratio and waist-to-height ratio are also useful indicators.

How do you reduce visceral fat?

Visceral fat is more responsive to lifestyle intervention than subcutaneous fat. Effective strategies include:

• Calorie deficit — overall weight loss reduces visceral fat preferentially compared with subcutaneous fat
• Aerobic exercise — regular moderate-to-vigorous aerobic activity reduces visceral fat even without significant overall weight loss
• Reduced refined carbohydrate and sugar intake — particularly fructose, which is preferentially metabolised to visceral fat
• Adequate sleep — sleep deprivation is associated with increased visceral fat accumulation
• Stress management — chronic cortisol elevation promotes visceral fat deposition

GLP-1 receptor agonists and dual GLP-1/GIP agonists have been shown in clinical trials to produce disproportionate reductions in visceral fat compared with overall weight loss — one of the mechanisms by which they reduce cardiovascular and metabolic risk.

Book a consultation with Weight Loss Wales to discuss your weight-related health risks and treatment options.