Carrying weight around your belly is a health risk. Find out why your waist measurement has overtaken BMI (body mass index) as the vital statistic

 
Expert opinion has moved on from BMI (although it remains a useful general guide). The standard method of assessing whether or not someone is obese is by checking their BMI, which combines measures of height and weight to assess a person’s risk of developing type 2 diabetes, heart disease, some cancers and other long-term conditions.

However, BMI takes no account of body composition – whether a person is muscular and fit; or abdominally obese, inactive and unfit. Indeed, relying on BMI has resulted in misleading claims where healthy, lean rugby players and heavy-set children have been categorised as obese, when in fact their ‘excess’ weight is healthy muscle.

The trouble with belly fat

Regardless of your total body weight, carrying fat around your middle (the classic ‘apple’ shape) is linked with an increased risk of colon and rectal cancer. It’s probably also linked to a higher risk of cancers of the pancreas and endometrium and, in post-menopausal women, breast cancer, according to the World Cancer Research Fund. HFG nutritionist Amanda Ursell adds that research suggests women with receptor-positive breast cancer who are obese at diagnosis risk up to a 30% higher rate of relapse.

‘What many people don’t realise is that extra fat around the middle is surprisingly “active”,’ she says. ‘It releases hormones and other chemicals that can make body cells divide far more often than usual, which can increase the risk of cancer.’ Overweight or obese people who intentionally lose weight have reduced levels of certain hormones that are related to cancer risk, such as insulin, oestrogens and androgens.

It’s more than skin deep

We also know that having a proportionally large middle means you’re likely to be carrying quite a bit of ‘visceral’ fat – the kind that pads itself around vital internal organs such as the heart and liver. This, in turn, seems to increase harmful blood fats and cholesterol, and interferes with the production of insulin, the hormone that controls levels of sugar in our blood.

The encouraging news: shedding general body fat seems to shrink a greater percentage of visceral fat. Doctors from McMaster University in Canada found that when obese patients burned off an average of 20% of their body weight, the layer of visceral fat clinging to organs shrank by an average of 32%.

How to measure your waist accurately

Food swaps to lose belly fat

*Weight-loss results will vary and are down to your individual circumstances and the amount of weight you have to lose.