If you’re naturally slim you might think that’s a sign that you’re in good health, however, outward appearances can be deceiving.
Someone who has a healthy BMI (between 18.5 and 24.9) but has an unhealthy diet, drinks to excess, smokes and has a sedentary lifestyle may have fat hidden inside their abdomen.


In fact, they may be considered TOFI: thin on the outside, fat on the inside. And this hidden ‘visceral’ fat, which settles on the internal organs is linked with a range of health problems including diabetes, high blood pressure and high cholesterol.

“The fat we carry around our waist is visceral,” says registered dietitian Alison Clark, who explains that when you develop a beer belly, that is also a sign of having visceral fat. Read on to find out if you have visceral fat – and what you can do about it.

What is visceral fat?

The weight that we accumulate under the skin on our arms, legs and bottom is called ‘subcutaneous fat’ and is “considered the more metabolically healthy type,” says immunologist Dr Jenna Macciochi in her book, Your Blueprint for Strong Immunity.
Visceral fat is deposited around the internal organs and is often called abdominal fat.

Read more about how to lose belly fat, the best exercises to burn fat and how to eat less sugar

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Man standing on scales

What are the dangers of this “active” abdominal fat?

Often called “active fat”, it's a risk factor for metabolic syndrome (the combination of diabetes, high blood pressure and obesity). “Visceral fat is metabolic, which means it produces chemicals and hormones that the body has to deal with, and is associated with hormone-driven cancers,” says Alison.

Visceral fat makes it harder for the hormone insulin to work and causes insulin resistance, which can lead to prediabetes and type 2 diabetes as well as obesity. It is a risk factor for 13 different cancers, including cancer of the stomach, gall bladder, breast, ovarian, endometrial, prostate, kidney and liver.

According to research from the American Heart +Association in 2021, having visceral fat can also be a sign that someone also has a fatty liver, which can lead to liver disease.

How do you know if you have visceral fat?

If you are overweight or obese, have an apple shape or have a beer belly, the chances are that you have some visceral fat.
Some smart scales use an electric current to calculate body composition and determine whether that is the case. But Alison prefers to use a tape measure. “It’s cheap, cost effective and easily repeated – great when you are making dietary and lifestyle changes, as improvements are motivating,” she says.

“Even if you have a healthy BMI, you can still have a waist circumference higher than those measurements. Don’t rely on your trouser size though – men’s waistbands will sit below the widest point of their waist.“To calculate your true waist measurement, find the halfway point between the bottom of your ribcage and the top of your hip bone,” she says.

If you’re of white European origin and your waist is higher than the recommended waist circumference of 31.5 inches for women and 37 inches for men, that indicates visceral fat. The British Heart Foundation states, “For men of African Caribbean, South Asian, Chinese and Japanese origin, a waist circumference above 35.4in is considered ‘very high risk’. For women from these groups, a waist above 31.5in is very high risk.

“This is because these groups tend to carry more fat and less muscle at the same weight as white Europeans,” the charity explains. “And the risk of diabetes and heart and circulatory diseases starts to increase at a lower weight gain than for Europeans.”

Healthy Mediterranean-style diet

What’s the best diet to get rid of visceral fat?

The Mediterranean diet is thought to be the best for our overall health. “Reduce your meat intake and eat more oily fish (salmon, trout, sardines and mackerel), and increase the variety of fruit and vegetables in your diet, aiming for up to 30 unique plants, including wholegrains, legumes, nuts, seeds and herbs a week.” says Alison.

How can lifestyle changes help to reduce this “hidden” fat?

“Sleep is very important,” says Alison. “It affects two hunger hormones: ghrelin, which drives appetite, and leptin, which makes you feel full. “If you have a sleep deficit, those hormones get disrupted and if you attempt to reduce your food intake you’ll be fighting a losing battle.”

Regular exercise is also crucial. The NHS advises that adults do some physical activity every day, either spreading 150 minutes of moderate intensity activity over a week, or 75 minutes of vigorous intensity spread over four or five days.

Alison adds, “Build muscle in your body. We start losing muscle mass at the age of 30, but it’s metabolically active and burns calories even while you’re sleeping. “You don’t have to go to the gym – you can just lift a litre bottle of water, or use your own body weight with squats.”

Further reading:

What is the best exercise for weight loss

What is the cheapest healthy diet

What is a balanced diet for men


What is a balanced diet for women

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