One in five Bay of Plenty 4-year-olds are overweight, obese or extremely obese, a new report shows.
A Tauranga dietitian says the obesity rate, described as an epidemic by one health boss, is "out of control".
The Toi Te Ora Public Health Service B4 School Check data body size technical report reveals in the Bay of Plenty DHB area, 21.4 per cent of 4880 4-year-old children checked in 2013 and 2014 were overweight, obese or extremely obese.
The proportion of extremely obese children was nine times what was expected from the growth standard.
The report said 18.7 per cent of girls and 23.9 per cent of boys were overweight, obese or extremely obese. Among Pacific Island children, 43.3 per cent were in that category compared with 29.7 per cent of Maori and 16.3 per cent of New Zealand-European children.
Western Bay Primary Health Organisation (PHO) chief executive Roger Taylor said the report highlighted a serious health problem.
"Unless significant thinking, response and resources are put into this, the cost to these children and their families and the country in the future is going to be monumental."
Phil Back, manager of general practice services, said the entire family had to be targeted to make changes, not just the children.
"We are trying to change public behaviour, it's the whole systems approach."
Medical Officer of Health, Dr Jim Miller, described the rise in obesity as an epidemic, and said it increased the risk of illnesses such as diabetes, heart disease, hip and knee problems, sleep issues and also had emotional effects.
About half of children who were obese at age 4 would go on to be obese as adults, he said. Nearly a third of children were either overweight or obese in New Zealand and about two-thirds of adults were overweight or obese.
"In the last 30 years, our food environment has changed. Processed and packaged foods that are high in sugar, fat, and salt or, put another way, 'energy dense' are much more readily available, tasty and relatively cheap.
"Sugary drinks, in particular, can increase the risk of being overweight or obese.
"While keeping active and exercising is generally good for health, it isn't really feasible for most people to exercise enough to balance the excess intake.''
Smart Nutrition dietitian Rebecca Bruce said obesity was a combination of children consuming high-fat and high-sugar convenience foods and high-sugar drinks, which could often be cheaper than healthier alternatives, on top of an increase in sedentary behaviour.
The statistics showed obesity in children and adults was getting "out of control" and becoming a vicious cycle with overweight parents and children, she said.
"It is hard to go from being obese to a healthy weight unless you target it earlier to break the cycle. There is a snowball effect as obesity is increasing through the generations.''
Ministry of Health childhood obesity champion Hayden McRobbie said it was working with DHBs and other health groups to support the "Raising Healthy Kids" targets and to share information and innovation.
• Sugary drink-free policies and healthy food initiatives led by schools, early childhood education centres, councils and workplaces.
• Food product reformulation that progressively reduces sugar content.
• Policies that increase availability and affordability of fresh and whole foods.
• Council planning to reduce children's exposure to unhealthy food (such as the high density of fast-food outlets and dairies that often seem to surround schools).
• Regulation of the marketing of unhealthy food and drink products so children can experience childhood free from the commercial interests of the food and beverage industry.
• A focus on investment in healthy pregnancies, the first nutritional environment that children experience.
Source: Medical officer of health Dr Neil de Wet