Globally, some 268 million children aged between five and 17 will be overweight by 2025 if current trends do not change, researchers have estimated.

Among these, 91 million will be obese.

According to the researchers, these figures will be a reality if policy interventions to tackle this issue prove ineffective.

They have also looked at obesity-related conditions and they estimate that by 2025, up to 12 million children will have impaired glucose tolerance, which often precedes type 2 diabetes, while four million will actually have type 2 diabetes.

A further 27 million will have high blood pressure and some 38 million will have hepatic steatosis, which is a build-up of fat in the liver.

"These forecasts should sound an alarm bell for health service managers and health professionals, who will have to deal with this rising tide of ill health following the obesity epidemic.

"In a sense, we hope these forecasts are wrong - they assume current trends continue, but we are urging governments to take strong measures to reduce childhood obesity and meet their agreed target of getting the levels of childhood obesity down to 2010 levels before we get to 2025," commented the research's co-author, Dr Tim Lobstein, policy director for the World Obesity Federation.

Details of these findings are published in the journal, Pediatric Obesity.