Abdominal Fat: When Does It Become a Health Risk?

There are two main types of adipose tissue in the abdominal area:

- subcutaneous fat, located immediately beneath the skin, which we can pinch between our fingers; - visceral fat, located deeper in the body, around abdominal organs such as the liver, pancreas, and intestines.

Both contribute to waist circumference, but visceral fat is more metabolically active. It is not simply a passive energy store, but biologically active tissue capable of releasing fatty acids, hormones, and inflammatory mediators.

When it accumulates in excess, visceral adipose tissue may become dysfunctional: it releases more fatty acids into the bloodstream, sustains chronic low-grade inflammation, and interferes with the action of insulin. Over time, these changes may contribute to an unfavourable metabolic profile.

In addition, excess energy is not always stored only in adipose tissue. Fat may also accumulate in organs where it should normally be present only in small amounts—for example, in the liver, muscles, pancreas, or around the heart. These deposits are known as ectopic fat and may directly impair the function of the affected organs.

Therefore, predominantly abdominal fat accumulation is associated with a higher risk of: - insulin resistance and type 2 diabetes; - high blood pressure; - increased triglycerides and decreased HDL cholesterol; - metabolic dysfunction-associated steatotic liver disease—MASLD, previously known as “non-alcoholic fatty liver disease”; - obstructive sleep apnoea; - cardiovascular disease.

The distribution of adipose tissue is influenced by several factors, not only by the amount of food consumed. These include: - genetic predisposition; - age; - sex and hormonal changes; - menopause; - a sedentary lifestyle; - insufficient sleep; - chronic stress; - excessive alcohol consumption; - certain medications and endocrine conditions; - loss of muscle mass with age.

Before menopause, oestrogen more commonly promotes fat storage around the hips and thighs. As oestrogen levels decline, fat distribution may shift towards the abdomen, even if the change in total body weight is not very large.

Short and fragmented sleep may affect appetite, insulin sensitivity, and food choices. Stress also does not “create” abdominal fat on its own, but it may contribute through poorer sleep, emotional eating, and prolonged exposure to cortisol.

Body mass index—BMI—is calculated by dividing weight in kilograms by the square of height in metres. It is a simple and useful tool for assessing populations, but it has important limitations.

BMI cannot distinguish between: - fat mass and muscle mass; - subcutaneous and visceral fat; - abdominal and predominantly gluteofemoral fat distribution; - excess fat with or without metabolic impairment.

A person with substantial muscle mass may have a high BMI without having a significant excess of adipose tissue. Conversely, someone may have a BMI considered normal but an increased waist circumference and low muscle mass. In this case, metabolic risk may be underestimated if the assessment stops at the scale.

For this reason, current recommendations suggest interpreting BMI together with waist circumference or the waist-to-height ratio. People with similar BMI values may have different cardiometabolic risks, and measures of central adiposity may complement the assessment.

For the most meaningful waist circumference measurement possible: 1. Use a flexible measuring tape and measure directly against the skin or over very thin clothing. 2. Stand upright, with the abdomen relaxed and weight distributed evenly across both feet. 3. Position the tape horizontally, midway between the lowest palpable rib and the upper edge of the iliac crest. 4. Do not tighten the tape or “suck in” your stomach. 5. Read the measurement at the end of a normal exhalation.

It is important to use the same method and, ideally, to measure under similar conditions each time. A difference of one or two centimetres from one day to the next may be influenced by bloating, bowel movements, or how the tape was positioned. The trend observed over time is more relevant than a single isolated measurement.

Which values indicate increased risk? For the European population, the International Diabetes Federation uses the following thresholds for abdominal obesity:

Women Men Increased cardiometabolic risk ≥80 cm ≥94 cm

These values should not be interpreted as a rigid boundary between “healthy” and “ill.” Risk increases progressively with waist circumference and should be assessed in the context of blood pressure, blood glucose, lipid profile, family history, smoking, physical activity, and any existing medical conditions.