Irish children are the eighth most overweight in Europe, and 58th in the world, according to a new study.
A sugar tax was introduced in yesterday's budget to tackle Ireland's obesity epidemic.
From April, the cost of a two-litre bottle of coke will go from €2.40 to €3.
The news comes as the number of obese children around the world has increased 10 times in the last four decades.
Research carried out in the UK by the University of Kent and University College London found there are now 124 million obese youngsters globally.
But numbers in the US and Europe appear to have plateaued.
Dr James Bentham carried out the study and says it's partly driven by falling poverty.
"We are seeing underweight continuing, it's going down slowly. And then this quite sharp rise in obesity.
"So it may be that more people are getting more nutrition then they need."