A wide-ranging study on health has revealed 40% of men and almost a third of women around the world are now overweight.
The International Day for Evaluation of Abdominal Obesity (IDEA) also found nearly a quarter of men and 27% of women are fat enough to be considered obese.
Doctors calculated the Body Mass Index (BMI) of 168,159 people aged 18 to 80 in 63 different countries.
Obesity rates differed between regions and for both men and women, ranging from a low of 7% in southern and eastern Asia, to 36% in Canada.
But heart disease rates were high in eastern Europe, where the frequency was 27% for men and 24% for women, the findings published in the journal Circulation show.
Study author Dr Beverly Balkau, from the French state-run medical research institute Inserm, in Villejuif, said: "This is the largest study to assess the frequency of adiposity (body fat) in the clinic, providing a snapshot of patients worldwide.
"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.
"Central adiposity adds significantly to the risk of developing heart disease and particularly of developing diabetes."
Dr Balkau is now calling for more action to stem the rising tide of obesity and excess weight, and said "a change is needed" to stop heart disease and diabetes getting worse.