Europe will face an obesity crisis of vast proportions by 2030, according to new World Health Organization projections, with many countries likely to see far more than half of adults above the healthy weight limit.

The figures, which predict 89% of Irish men and 77% of Greek men will be overweight by 2030, present “a worrying picture of rising obesity across Europe”, researchers said, with very few countries showing decreasing trends.

“Although there is no silver bullet for tackling the epidemic, governments must do more to restrict unhealthy food marketing and make healthy food more affordable,” said Dr Laura Webber of the UK Health Forum, which worked with the WHO and the European Commission to produce the new projections.

She also said insufficient data from some countries in the WHO’s European region – which comprises 53 nations – made surveillance of obesity more difficult, hampering efforts to make accurate predictions.

A body mass index (BMI) – calculated by dividing a person’s weight in kilograms by the square of their height in metres – of more than 25 is classified as overweight. A BMI of more than 30 is classified as obese.

The latest predictions used data from across the region and compared the proportions of overweight people and obese people in 2010 with projected future levels.

They showed that by 2030, a third of women in the UK are forecast to be obese, compared with 26% in 2010. For British men, almost three-quarters will be overweight and 36% are likely to be obese in 2030, compared with 70% and 26% respectively in 2010.

The researchers, who were due to present their data at the European Congress on Obesity in Prague on Wednesday (6 May), said other countries with projected steep rises in obesity included Greece, Spain, Sweden, Austria and the Czech Republic.

The proportion of obese Greek men will more than double from 20% to 44% between 2010 and 2030, and the proportion of obese Greek women is seen doubling to 40%.

Even in countries usually recording a lower prevalence of obesity, such as Sweden, obesity rates are predicted to rise sharply. An estimated 26% of Swedish men will be obese by 2030 compared with 14% in 2010, while for women obesity rates will rise from 12% to 22%.