Checking your waistline with a tape measure is a better predictor of your health prospects than your weight on the bathroom scales, anti-obesity campaigners will say today.
That is worse news for men whose excess fat is more likely to be of the big-belly type than for women whose excess pounds are often round the bum, hips and thighs.
Put another way, those who are pear-shaped may have a rosier future than those with a more rounded "apple" look.
Anthony Barnett, professor of medicine at Birmingham University, warns that men with what many might not regard as a spare tyre, a 37 inch (94cm) waist, could be significantly raising their risks of two major diseases.
"Waist measurements can predict the risk of type 2 diabetes and heart disease more accurately than weight," said Professor Barnett last night, on the eve of a National Obesity Forum conference in London.
"Men with waists of more than 40 inches (102cm) and women with waist measurements of more than 35 inches (89cm) are at an incredibly high risk.
"Thicker waistlines may double to quadruple these risks, compared to those with slimmer waistlines.
"Even a lower waist of 37 inches in men and 32 inches (81cm) in women may significantly raise the risk of either of these diseases, if not both."
A person's waist size indicates the fat around the abdomen, in the liver and in the gut. The cells here can pump out excessive amounts of chemicals that threaten the insulin system, the hormone that controls blood-sugar levels, and can raise blood pressure and cholesterol.
Type 2 diabetes is caused by insulin resistance, triggered partly by excess weight around the abdomen. Insulin is produced in the pancreas and often stops working properly in overweight or obese people. The larger their waistline, the more resistant to insulin they become.
Prof Barnett said: "The more resistant you are to insulin, the more the body has to produce from the pancreas gland in order to have the same effect. Eventually, the pancreas becomes exhausted and either stops producing as much insulin, or in severe cases, may stop producing insulin altogether."
David Haslam, a Hertfordshire GP, who chairs the National Obesity Forum, said there was an urgent need to communicate the dangers to men. "Because of blokeism, they never go within a million miles of their doctor. They are pathetic at looking after themselves and seeking care."
