A Consultant Paediatrician at Drumlin's Children's Hospital says if we're to tackle childhood obesity then we must look at every aspect of a child's life.
Declan Cody's comments come as the latest statistics show a quarter of all nine year olds in Ireland are now overweight or obese.
Yesterday, Fine Gael Senator and former Irish Athlete Emanon Coughlan called for PE to be made a Leaving Cert subject.
But Mr Cody says it shouldn't just be left up to schools to instil a healthier lifestyle into children: "Really, changes have to be made across the board in terms of how they're living, reducing portion sizes, reducing treats and fizzy drinks.
"Of course we have to make them more active too. Getting them to walk to school, get them to walk back from school and of course incorporate PE into this as well to increase daily physical activity."