The hourglass figure has fallen victim to the sands of time - and a surfeit of calories.

In the heyday of Sophia Loren and Marilyn Monroe, women aspired to a wasp waist which accentuated their curves.

Nowadays bust and hips are bigger than ever. But the effect is destroyed by the fact that ladies hardly go in at the middle any more.

Waspiest of waists: La Loren in the 1960 film The Millionairess

Data shows that over the past half century the average British woman's waist has expanded by an astonishing 6.8 inches to 34.4 inches.

Since 1951, the average bust has increased by 2in to 39in and hips by a further 2in to 41in. As a result, Miss or Mrs Average is now 10lb heavier.

The survey of 9,000 British men and women by researchers at University College London discovered that men have gone through a similar expansion.

British males are now an average of seven inches fatter around the waist and 18lb heavier than they were during the post-war years.

The dramatic statistics were revealed as a senior Government minister claimed that almost half of British children will be dangerously overweight by 2050.

Over the past 12 years, the proportion of children aged two to ten and classified as obese has jumped from less than 10 per cent to almost 17.

Ed Balls, Secretary of State for Children, Schools and Families, said: "If that trend continues, by mid-century we'd be getting close to half of all children classified as obese."

He added: "It's clearly important that we act."

The rapid change in shape and weight of our bodies has been attributed to an increased calorie intake coupled with a more sedentary lifestyle.

Some 22 per cent of British adults are now considered to be obese - meaning that they are so overweight that it threatens their health.

The so-called 'obesity epidemic' is linked to increased incidences of heart disease, diabetes and high blood pressure and has been calculated to cost the NHS some £7.4billion a year.

Last month, the head of the British Medical Association controversially argued that we need to stop pussyfooting around the problem by "overmedicalising" the issue of obesity.

Dr Hamish Meldrum said: "We are tending to say, 'This patient has a hyper-appetite problem' rather than maybe, 'They are eating too much'."

Despite the depressing statistics, Britons can take some comfort that we are still a significant way behind Americans, who remain the fattest nation in the developed world.

According to the UCL study, British women are an average of 3lb lighter and 0.4in slimmer than their U.S. counterparts. British men are 12lb month, lighter and 1.1in thinner than the average American.

Children who eat meals with their family rather than snacking alone are less likely to become fat, research suggests.

Researchers at the University of Minnesota studied 1,500 students' eating habits over a five-year period.

They found that those who regularly sat down for a communal family meal tended to grow into adults who ate more fruit and vegetables and had fewer fizzy drinks.

They also had a greater-than-average daily intake of healthy nutrients such as calcium, magnesium, potassium and fibre. They tended to sit down for breakfast rather than eating on the run.

And they were more likely to eat supper at the dining table rather than those who, as youngsters, ate alone or in front of the television.

In the Journal of the American Dietetic Association, the researchers said: "Food and nutrition professionals should encourage families to share meals as often as practically possible."