The number of obese children and adults in the UK will rise substantially by 2050 – and by more than half in some age groups, figures suggest. The most comprehensive global analysis to date predicts that children as young as five will be much more likely to be obese in the coming decades.

Responding to the findings, published in the Lancet medical journal, experts said the global picture represents a “profound tragedy and a monumental societal failure”. The data for the UK has been analysed by the PA news agency.

It shows that for children aged five to 14, obesity will rise from 12.0% of girls in 2021 to 18.4% in 2050, and from 9.9% to 15.5% in boys over the same period. Within this age group, the rise among five to nine-year-old girls will be from 12.6% to 19.3%, and from 9.8% to 15.3% among boys.

Meanwhile, in 10 to 14-year-olds, the rise is from 11.3% to 17.5% in girls, and from 10.0% to 15.7% in boys. The estimated prevalence of obesity for 15 to 24-year-olds is 15.4% in 2021 among girls, rising to 22.9% in 2050.

In boys, the jump is from 12.1% to 18.3%. Taking being overweight and obesity together, some 39.2% of girls aged five to nine in the UK will be obese in 2050, while 31.3% of boys will also be overweight or obese.In 10 to 14-year-olds, some 43.2% of girls will be overweight or obese in 2050, up from 34.7%, while 37.6% of boys will be, up from 29.9%.

Among those aged 15 to 19, the rise in being overweight and obesity is from 32.6% to 41.0% of girls, and from 28.2% to 35.6% of boys. The data further shows that obesity in adults aged 25 and over will jump from 31.7% of women in 2021 to 42.6% in 2050, while obesity in men will rise from 29.3% to 39.5%.

When combined, some 23.4 million adults in this age group in the UK will be obese. When the number of overweight people are added, some 43.4 million adults aged 25 and over are expected to either be overweight or obese.

Overall, the Lancet study suggested more than half of adults and a third of children and adolescents across the globe will be overweight or obese by 2050. Experts said overweight and obesity rates in adults and children have more than doubled over the past three decades (1990-2021), affecting 2.11 billion adults and 493 million young people worldwide in 2021.

Without “urgent policy reform and action”, around 60% of adults (3.8 billion) and a third (31%) of all children and adolescents (746 million) are forecast to be either overweight or obese by 2050. Globally, the predicted surge in child and adolescent obesity is also expected to outpace the increase in youngsters being overweight.

Lead author, Professor Emmanuela Gakidou, from the Institute for Health Metrics and Evaluation at the University of Washington in the US, said: “The unprecedented global epidemic of overweight and obesity is a profound tragedy and a monumental societal failure.

“Governments and the public health community can use our country-specific estimates on the stage, timing, and speed of current and forecasted transitions in weight to identify priority populations experiencing the greatest burdens of obesity who require immediate intervention and treatment, and those that remain predominantly overweight and should be primarily targeted with prevention strategies.”

The authors said more recent generations are gaining weight faster than previous ones and obesity is occurring earlier, increasing the risk of type 2 diabetes, high blood pressure, heart disease and cancer at younger ages.

The study did not consider the potential impact of weight-loss injections, which may alter the longer-term forecasting trends of overweight and obesity.

Professor Volkan Yumuk, president of the European Association for the Study of Obesity, said: “Because obesity is both a chronic disease in its own right and the cause of other chronic diseases and conditions, this unprecedented public health emergency will require co-ordinated policy action across Europe.”