The average Irish 14-year-old boy is 65 per cent heavier than he was in 1948, a conference on obesity heard.
Though they are also on average 17cms (5.5 inches) taller, they are still much fatter than they were seven decades ago.
Consultant endocrinologist Dr Francis Finucane said the research is based on a study in Cork that reveals the average 14-year-old boy weighed 37kgs in 1948 rising to 61kgs in 2002, a figure that has remained static since.
He stated that nutrition is a significant factor in the huge increases in height and weight of Irish teenagers in the last 70 years.
Dr Finucane told a conference on obesity that between one in five and one in four young people in Ireland are obese which is about average for Europe.
However, he said childhood screening would be an expensive and ineffective way of combating the problem of obesity and might do more harm than good.
“It is expensive and it often flags something for parents who are unaware of the issue, but there are plenty of downsides we don’t know about it,” he told the weight management interest group study day at St James Hospital.