A new global study finds that about half of the world's women and about two-thirds of the world's men are either overweight or obese. And Canada has the dubious honour of having one of the highest rates of obesity recorded.

The huge study -- the largest ever to assess obesity worldwide, according to its lead author Beverley Balkau, director of research at INSERM in Villejuif, France -- is published in Circulation: Journal of the American Heart Association.

It looked at 168,159 people (69,409 men, 98,750 women) in 63 countries across five continents.

The study was conducted on two half-days by randomly selected physicians in both urban and rural areas of their countries, in a study dubbed "The International Day for Evaluation of Abdominal Obesity (IDEA)."

The doctors recorded the age, gender and presence of heart disease or diabetes in their patients and measured their waist circumferences. Weight and height were measured and body mass index (BMI) was also calculated.

Balkau says taking the waist measurement was particularly important since the measurement is "a more powerful clinical marker of heart disease and diabetes than BMI." Plus, it's an easy measurement to record.

The researchers found that about 40 per cent of men and 30 per cent of women around the world are overweight, while another 24 per cent of men and 27 per cent of women are obese.

"The study results show that excess body weight is pandemic, with one-half to two-thirds of the overall study population being overweight or obese," Balkau said.

Obesity, particularly the kind that involves fat settling around the abdomen, has become a major public health problem that threatens to overwhelm already extended health care services in many countries, she says.

Using the waist measurements, Balkau's team found that more than half the study population -- 56 per cent of men and 71 per cent of women -- had excess abdominal fat. That was defined as a waist circumference greater than 94 cm (37 inches) in men and 80 cm (31.5 inches) in women.

"Overall, there's a significant increase in the frequency of heart disease and diabetes with increasing waist circumference," Balkau noted.

"For men, each increase of approximately 5.5 inches (14 centimeters) means an increased frequency of about 35 per cent for heart disease and for women an increase of approximately six inches (15 centimeters) equates to a 40 per cent increase for heart disease. Even in people who are lean, an increasing waist circumference means increasing risk for heart disease and diabetes."

As measured by BMI, more than 60 per cent of men and 50 per cent of women were either overweight or obese, with a BMI of 25 or more.

The overall frequency of overweight was 40 per cent in men and 30 per cent in women, with similar frequency across geographical regions. On the other hand, the frequency of obesity (defined as a BMI of 30 or more) differed between regions.

The frequency of obesity ranged from a low of seven per cent in both men and women in South and East Asia, to 36 per cent in Canadian men and women.

The study showed the overall frequency of heart disease was 16 per cent in men and 13 per cent in women. And the overall frequency of diabetes was 13 per cent of men and 11 per cent of women were diagnosed with diabetes.

Both diabetes and heart disease were more common in men than women.

Prevention

Balkau called upon governments to take more preventive measures to stem the tide of obesity and overweight, such as providing more access to physical activity and encouraging people to exercise.

"Physical activity and good nutrition are the key," she said. "A change is needed or the public health situation for heart disease and diabetes will become worse."

A Canadian doctor says Canada has one of the highest childhood obesity rates in the world. Dr. David Lau calls it a worrisome phenomenon that requires all levels of a child's life -- from the home, to schools, to the greater community -- to work together in order to stop.

"We have measured data now that tells us that one in four or five children has a weight problem and one in 10 kids is truly obese," Lau, also a professor of medicine at the University of Calgary, told CTV Newsnet on Monday.

"So what is more important is the fact that when children are overweight they tend to be overweight teenagers and eventually overweight adults. And we're now seeing more and more overweight teenagers tracking all the adult problems such as sugar diabetes high blood pressure and even fatty livers."

Lau says the easy availability of energy-dense foods and calorie-rich juices and soft drinks, combined with a lack of physical activity, are combining to cause the obesity epidemic in children.