Auckland school children are almost 2kg heavier than they were seven years ago.
The third annual Healthy Auckland Together monitoring report, released today, shows the average weight of Auckland children aged up to 14 was 1.8kg heavier in 2017 compared to 2011.
The average weight grew from 33.9kg to 35.7kg.
Between 2011/12 and 2016/17 the proportion of obese or overweight children in that age group jumped from 28 per cent to 37 per cent.
In contrast, the proportion of Auckland 4-year-olds who were obese fell from 10.4 per cent in 2012 to 8.2 per cent in 2016.
Healthy Auckland Together spokesman Dr Michael Hale said limiting screen time, encouraging physical play and a focus on healthy lunchboxes seemed to be keeping pre-schoolers at a more healthy weight but as children aged, the influence of parents decreased.
"In the primary and secondary school years, we see a decline in the influence of parents, the pull of unhealthy food outside the home, and long hours spent watching screens. This is apparent in the rise in the levels of overweight and obese children up to the age of 14," he said.
"What our local neighbourhoods look like really comes into play then. Neighbourhoods and schools aren't the good promoters of healthy lifestyles they used to be."
Children at school, especially secondary school, often had unhealthy food available in the tuckshop and in vending machines, Hale said. Only half of primary schools and 11 per cent of secondary schools had water-only policies or restricted sales of high fat, high sugar food in the tuck shop.
Hale said increasing exposure to advertisements and marketing of unhealthy food was also influencing the choices young people made.
Declining physical activity was another contributing factor. Children in lower socioeconomic areas used to be more likely to walk, bike or scooter to school (56 per cent between 2011-14) but were now being dropped at the gates at similar rates to all other children (43 per cent), the report showed.
One of the problems with overweight children was that excess weight continued into adulthood and obesity was now the greatest risk driving death and disability in New Zealand - surpassing tobacco.
New Zealand was again ranked the world's third fattest country last year with 32 per cent of adults obese.
In Auckland the rate was similar with 30.4 per cent of adults obese - an increase of about a fifth in the last decade.
But across Auckland, Counties Manukau had the highest rate of obesity at almost 40 per cent compared to about 25 per cent in the Auckland and Waitemata regions last year.
And as with most of the health measures, the figures for adults and children were worst in low socio-economic areas, the report found.
"Although economic and family stresses contribute to obesity, poorer neighbourhoods themselves can nudge people towards unhealthy behaviours," Hale said.
"We know that suburbs with high socioeconomic deprivation have a greater concentration of fast food outlets compared with fruit and vegetable shops."
The data from checks of almost 80,000 children's teeth showed those living in the poorest neighbourhoods were 12 times more likely to have the worst oral health.
Hale said it was likely that excess sugar consumption was largely responsible with low prices, high availability and heavy marketing of sugary products encouraging consumption.
Statistics back up that assumption showing that, in 2016, 4-year-olds in the obese category were 11 per cent less likely than those in the normal or underweight category to have healthy teeth and gums.
Hale said solutions to obesity needed to combine schools, local and central government.
Schools needed to encourage healthy lifestyles by selling healthy food while local and central government needed to legislate around the advertising and marketing of unhealthy food and place regulations around what food could be sold in schools, he said.
Students take action
A group of Waitākere College students have taken it upon themselves to tackle some of the causes of growing obesity rates.
The school set up a Health Academy for students interested in pursuing a medical career and in 2016 the group set out to make their school healthier.
Since then the students have surveyed their peers and lobbied the board of trustees for change.
"The survey showed most of them were buying sugary drinks because they were a lot cheaper and they weren't drinking from the water fountains because they weren't in the best condition," 17-year-old Ashley Ah Chong said.
The school had since installed six new water fountains with bottle fillers so students could refill water bottles.
They also succeeded in encouraging the school tuck shop to sell healthier food, Zeo Haami, 17, said.
"There's a lot more wraps. There's hardly any sugary drinks. Instead of donuts there are sandwiches and hot food."
And the new options meant the line for the tuck shop had never been longer, according to the students.
Zeo said the process had influenced how she wanted to live and opened her eyes to the situation of many Māori and Pacific communities where rates of obesity and diabetes were climbing.
It was important to get the message across while people were still young so they could form healthy habits and encourage their families, she said.
Healthy Auckland Together spokesman Dr Michael Hale said all schools needed to make similar changes so children learnt what a healthy lifestyle looked like from a young age.