More than 28,000 people had inpatient stays in Irish hospitals in a four-year period because of Type 2 diabetes.
Between 6,000 and 8,000 people were admitted every year between 2015 and 2018.
They include 148 young adults and 31 children, according to Freedom of Information figures.
Professor Niall Moyna, from the school of health and human performance in DCU, says he is not surprised by the new statistics.
"This is what we have been expecting from this explosion in obesity over the last 10-15 years," said Prof. Moyna.
It was a timebomb that has exploded and these are the manifestations.
"Type 2 diabetes is primarily because of our lifestyle - it is lack of exercise and poor diet.
"Through changing those we could have a profound effect. In fact, there is no reason why anyone should be developing Type 2 diabetes particularly prior to the age of 65-75."
Type 2 diabetes due to a disregulation of your sugar so your blood sugar levels are higher than they should be, he said.
Prof. Moyna said it is due to an over-consumption of carbohydrates and sugar as well as lack of exercise.
"The sad thing now is that it is starting earlier and earlier. It used to be called Adult On-set Diabetes because it normally occurred in people in their 50s and 60s.
"We now see it in prepubescent and adolescent children."
