WHO IS MOST AT RISK?

VERY small amounts of visceral fat are normal. Studies suggest men of normal weight carry 4½ lb and women 3lb of visceral fat.

If they are obese, the average is 11½lb for men and 8 lb for women.

Men are more susceptible to the problem, as they tend to store fat around their tummies. Women generally store it on their hips and thighs. Having fat here is safer, because it cannot spread to the organs.

This explains why although women have a higher body fat percentage than men, they are less prone to heart disease and diabetes and generally live longer. Certain ethnicities — including people of South Asian origin — are more likely to carry excess weight around the middle, so these groups tend to develop diabetes at a lower overall weight than others.

‘The number one thing that dictates where your fat goes is genetics,’ says Professor Naveed Sattar. ‘Smoking may also alter your fat distribution and cause you to put it on centrally.’

After the menopause, women store more fat around their waist — possibly because oestrogen changes the behaviour of proteins and enzymes that control fat storage, says Dr Louise Thomas.

‘One of the reasons for women having much higher rates of heart disease after the menopause is thought to be the change in body fat distribution from pear to apple shape.’