Almost 32% of seven-year-olds in Ireland are overweight or obese, an Oireachtas Committee on Health and Children has heard.
Ireland now ranks fifth in the European Union when it comes to childhood obesity.
Consultant paediatrician Dr Sinead Murphy told the committee that the situation is failing to stabilise and is getting worse.
She said if the problem is not tackled, 47% of adults in Ireland will be obese by 2030.
Dr Murphy told the committee that the cost of adult obesity, which is currently €1bn a year, will rise unless the issue of obesity in children is addressed.
Irish Nutrition and Dietetic Institute President Richelle Flanagan said that the State was not meeting its duty of care to its children.
Ms Flanagan requested that the Department of Health consider the childhood obesity programme in October's budget, as current funding provided by Temple Street Children's Hospital will cease at the end of the year.