Their natural inclination to be active has been hampered by technology to a point where children's activity has fallen by a third in less than a century.
Experts recommend children get at least one hour of exercise a day. Twenty years ago the average child would have achieved that before the school bell sounded.
Structured exercise is seen as a chore by many children but traditional games of running, skipping and jumping, which have sadly fallen out of favour, are just as good for improving fitness.
Children are not alone in this trend, adults are also living less active lives.
The net effect of this change in culture is that excessive weight and obesity costs the country between $722 million and $849 million a year in healthcare costs and lost productivity.
The good news is this increase in obesity can be changed through lifestyle choices. The bad news is that it appears not enough is being done to reverse the trend.
New Zealand performs poorly on policies such as reducing junk food marketing to children, simple front-of-packet traffic light labelling on processed food and giving the food industry too much influence in developing public policies around food.
This must change but it is worth noting that while policy might be used as a tool to encourage healthy eating and exercise, it's ultimately a parent's responsibility to encourage their children to live healthy, active lives.
This can be as simple as turning off the TV, game console or computer and ushering a child out the door to play outside for an hour or two.