Obesity experts will warn this week that the traditional pear-shaped female form, where weight is carried on the hips and thighs, is on the decline and women are turning apple shaped - with growing beer bellies, a trait usually associated with overweight men.
The National Obesity Forum, which holds its annual conference tomorrow and Tuesday, says that more women are becoming apple shaped, which is less healthy because it means they carry excess fat around their abdomen which can lead to heart disease and diabetes.
Dr Ian Campbell, the forum's president, said many factors, including the Western world's increasing reliance on private cars, were responsible for this worrying transformation and that even teenage girls were at risk. "We know that most women are pear shaped which is less of a health concern," he said. "But we are seeing women who are developing apple-shaped figures where they are putting on weight around the abdomen. This poses serious health risks."
Body shape is generally defined by the main part of the body where fat is stored. Until now, most British women have fallen into the category of pear shape, in which fat is stored below the waistline on the hips, thighs and bottoms. In contrast, those who are "apples" have relatively slim thighs and upper legs, flat bottoms but prominent stomachs. Big bottoms and large thighs may be considered a curse by some British females but a study published earlier this year by researchers in Copenhagen concluded that pear-shaped figures have healthier types of fat than those who are apple shaped.
The reason is that fat stored around the hips is more likely to produce adiponectin, a natural substance from fat cells which is associated with a reduced risk of heart disease. In contrast, abdominal fat tends to be more deeply stored. It drains directly into the liver and secretes fatty acids, hormones and proteins into the bloodstream.
The rates of obesity for women have risen from 18 per cent over a decade ago to 22 per cent in 2002.
The National Obesity Forum says that waist size is a crucial indicator in determining obesity. For example, a woman with a waistline bigger than 32 inches is at an increased risk of diabetes and heart disease.
But losing four inches around the middle is the equivalent of losing 22lb of dangerous abdominal fat for anyone weighing 15.7 stone.
Dr Susan Jebb, head of the Medical Research Council Nutrition Research centre in Cambridge, warned that people who consider themselves borderline overweight may in fact be at risk of serious illness if they carry abdominal fat or are apple shaped.
"Women are getting fatter generally, and therefore they are getting more abdominally obese by default," she said. "Unfortunately, all that people can do to lose abdominal fat is to lose weight."
Additional reporting by Tom Anderson
'I'm a natural fat girl'
British women have expanded in every direction since the end of the post-war era of food rationing. According to doctors, the ideal waist measurement for women is 32 inches and below, yet the average measurement for a woman's waist is now 34 inches, an increase of six and a half inches over the past 50 years.
Singer Charlotte Church is a typical example of a woman with "apple" tendencies. With a naturally curvy figure, she has always insisted that she would never go on a diet. In a recent interview, the 19-year-old said: "I love a good curry and a fry-up. I'm a natural fat girl."
But her love of fast-food and drinking means that she could be at risk of health problems in later life.
Brigitte Nielsen or Grace Jones. Broad torso and smaller on the bottom half. Although carrots tend to have slim hips they also have slim waists, so they do not have a tendency to deposit fat in the abdominal area.
Models Erin O'Connor and Twiggy. Tall, slim and tend to find it easy to hide excess weight and also to lose extra pounds. They are less at risk of coronary heart disease but more at risk of cancer.
Jennifer Lopez or Kate Winslet. They store fat below the waist on their hips, thighs and bottoms, which often leads to cellulite. Doctors consider it a healthy shape although there is a risk of arthritis in later life.Reuse content