Obesity increases heart disease risk
Between half and two-thirds of men and women in 63 countries across five continents - not including the US - were overweight or obese in 2006.
The Circulation journal study included over 168,000 people evaluated by a primary care doctor.
Experts said the findings were deeply worrying.
People who are overweight have a higher risk of heart disease, Type II diabetes and other diseases including some cancers.
The International Day for the Evaluation of Obesity (IDEA) study looked at two measures of fatness - waist circumference and a calculation called body mass index or BMI.
A BMI (weight in kg divided by square of height in meters) of 18.5 to 25 is considered healthy.
A BMI over 25 is deemed overweight and greater than 30 is obese.
Just 7% of people in eastern Asia were obese, compared to 36% of people seeing their doctors in Canada, 38% of women in Middle Eastern countries and 40% in South Africa.
Canada and South Africa led in the percentage of overweight people, with an average BMI of 29 among both men and women in Canada and 29 among South African women.
In Northern Europe men had an average BMI of 27 and women 26 - just into the overweight category. In southern Europe, the average BMI was 28. In Australia BMI was 28 for men and 27.5 for women while in Latin America the average BMI was just under 28.
Waist circumference was also high - 56% of men and 71% of women carried too much weight around their middle.
"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," said Beverley Balkau, director of research at the French National health research institute INSERM in Villejuif, who led the study.
That puts the rest of the world close to par with the US, long considered the country with the worst weight problem.
An estimated two-thirds of Americans are overweight and a third of these are obese. In the US, the lifetime risk of developing diabetes, is also high - 33% for men and 38% for women.
In the study, the overall frequency of heart disease was 16% in men and 13% in women. There was a high frequency of heart disease in Eastern European men, 27%, and women, 24%, in contrast to Canada where the frequency in women was 8%, and in men 16%.
The frequency of diabetes varied across regions. Overall, 13% of men and 11% of women were diagnosed with diabetes.
Ellen Mason of the British Heart Foundation said: "It is tragic irony that whilst much of the world is starving, many developed countries across the world are in the grips of an obesity crisis.
"Whilst it is vital not to stigmatise people in our society for being overweight, it is important we all know the health risks from being obese. The worrying increase of diabetes in the UK is clearly linked to rising obesity levels and plummeting physical activity levels. Being obese or diabetic, or worse, both, increases your chance of getting heart disease.
"Whilst the UK may not be the worst offender in this global study, we are aware that it's a major health issue in our country. After seeing the heart attack death rate reduce in the UK in the last few years, there is a real risk that this figure could go back up if diabetes and obesity continue to rise as they currently are."