'Approximately 80% of heart disease, stroke and type 2 diabetes -- and 40% of cancer -- could be avoided through healthy diet, regular physical activity and avoidance of tobacco use.'

The organization urges individuals to adopt a healthy diet, engage in physical activity and refrain from tobacco use in order to reduce the risk of heart disease and stroke associated with overweight and obesity.

Cardiovascular disease is the number one cause of death, notes WHO, accounting for over 17 million fatalities every year.

Not Just Wealthy Nations

Body mass index, or BMI, is calculated by dividing weight in pounds by the product of height in inches x height in inches and then multiplying the result by 703; alternatively, by dividing weight in kilograms by the product of height in meters x height in meters.

Overweight is defined as BMI greater than 25; obesity is defined as BMI greater than 30. High body mass index is a major risk factor for heart disease, stroke, type 2 diabetes and other chronic diseases.

Overweight and obesity once were considered problems for wealthy countries alone, but the conditions are rising dramatically in low- and middle-income countries. There has been a global shift toward increased calorie intake, along with consumption of larger amounts of fat, salt and sugar.

Compounding the problem, modern work and urbanization have resulted in more sedentary lifestyles.

Overwhelming Chronic Disease Burden

More than 75% of women over the age of 30 are now overweight in countries as diverse as Barbados, Egypt, Malta, Mexico, South Africa, Turkey and the United States, WHO estimates.

Over 75% of men are now overweight in, for example, Argentina, Germany, Greece, Kuwait, New Zealand, Samoa and the United Kingdom.

Notably, the Western Pacific islands of Nauru and Tonga have the highest global prevalence of overweight with nine out of every 10 adults in that category.

"The sheer magnitude of the overweight and obesity problem is staggering," says Dr. Catherine Le-Gales Camus, WHO Assistant Director-General of Noncommunicable Diseases and Mental Health.

"The rapid increase of overweight and obesity in many low and middle income countries foretells an overwhelming chronic disease burden in these countries in the next 10 to 20 years, if action is not taken now," she predicts.

Largely Preventable

Over the next ten years, cardiovascular disease -- primarily heart disease and stroke -- will increase most notably in the regions of the Eastern Mediterranean and Africa, where cardiovascular disease-related deaths are predicted to rise by over 25%, according to WHO.

"The real tragedy is that overweight and obesity, and their related chronic diseases, are largely preventable," says Dr. Robert Beaglehole, WHO Director of Chronic Diseases and Health Promotion.

"Approximately 80% of heart disease, stroke and type 2 diabetes -- and 40% of cancer -- could be avoided through healthy diet, regular physical activity and avoidance of tobacco use," he points out.

The WHO Global Strategy on Diet, Physical Activity and Health and the WHO Framework Convention on Tobacco Control describe the actions needed to reduce tobacco use and support the adoption of healthy diets and regular physical activity.