68 percent Americans found to be overweight as obesity becomes global epidemic

Studies conducted jointly by researchers at Imperial College London and Harvard University, published in the medical journal The Lancet, show that obesity worldwide almost doubled in the decades between 1980 and 2008.

In 2008, 9.8 percent of men and 13.8% of women - more than half a billion adults - were found to be obese, as measured by the Body Mass Index or BMI. BMI is usually measured by dividing the weight of an individual in kilograms by the square of his height in meters. A BMI in excess of 25 leads to being labeled as 'overweight' while BMI of above 30 is considered to be indicative of obesity.

One of the most conspicuous conclusions from the study was that obesity is no longer an affliction in the richer, developed nations only, but was fast spreading to low and middle-income nations too. Globally, the Pacific Island nations were found to have the highest BMI average.

In alarming news for Americans, BMI rose the fastest in the U.S. during the entire 28-year period studied, according to results of the study published in Bloomberg; in 2008, 68 per cent of Americans were found to be overweight while close to 34 percent were obese.

Among the other developed nations, UK, Australia and New Zealand also witnessed significant increase in body mass. The study also warns that obesity is generally a high risk factor for cardiovascular diseases, diabetes, cancer and musculo-skeletal disorders, which cause 3 million deaths worldwide each year.

In some good news for the U.S. and other high-income nations, uncontrolled hypertension (high blood pressure) - which leads to heart disease and causes 7 million deaths a year -- fell significantly over the period. Blood pressure readings in the U.S. in fact were among the lowest recorded. Average levels of total blood cholesterol - another trigger for cardio-vascular diseases - also fell. The authors of the study ascribe this to improved medical monitoring and anti-hypertensive medication, reduced salt intake and shifts towards healthier, unsaturated fats.

The studies were funded by the Bill and Melinda Gates Foundation and the World Health Organization.