We are what, when and how we eat

A high proportion of children in Aotearoa New Zealand are overweight or obese prompting a new report on the causes of the problem and ways parents and healthcare providers can tackle it.

Download the evidence brief

Analysis of Aotearoa New Zealand’s high incidence of childhood obesity has highlighted the significant degree to which weight problems can be triggered both before birth and in early childhood.

Dr Felicia Low, head of the Knowledge Hub for Maternal and Child Health at Koi Tū, has produced an evidence brief Childhood obesity: reducing the risk through early life measures, which found mounting evidence linking childhood-obesity risk to early-life factors and caregiver feeding practices.

“The environmental conditions encountered from conception through to the first few years after birth play a major role in shaping a person’s health status in later life,” says Dr Low, whose work is funded by the Wright Family Foundation.

In relation to obesity, this is shifting the focus from the conventional “energy in, energy out” argument that weight reduction is a matter of individuals simply choosing to eat less.

“There is awareness that overconsumption of food may lead to excessive weight in children. But there is less recognition of such factors as in-utero nutrition and parent or caregiver feeding practices,” says Dr Low.

Her analysis of the contribution of early-life nutrition to weight problems in children, including duration of breastfeeding and establishment of meal-time habits, offers helpful clues to effective ways of reducing the problem, which affects nearly a third of two- to 14-year-olds and is significantly worse in Māori and Pacific children.

“Having obesity puts children at greater risk of developing asthma, type 2 diabetes, digestive problems and joint pain, as well as depression and anxiety,” Dr Low says.

What’s more children with obesity often grow up to become adults with obesity, with health problems tracking throughout their life.

As Dr Low’s work notes, it’s increasingly clear that a parent’s weight or metabolic health can have a direct, biological influence on their children’s health.

Several studies have found associations between higher maternal body mass index (BMI) during pregnancy and BMI of children as adolescents or adults.

A father’s nutritional state may be important too: there is increasing evidence that children whose fathers had a high BMI at the time of conception also tend to have higher BMI and clinical indicators of obesity, heart disease and diabetes.

Two-thirds of women and 71 percent of men in Aotearoa New Zealand are overweight or obese.

“The data suggest a large proportion of New Zealand babies may be exposed to prenatal factors that affect their health, both in the short term through negative birth outcomes and in the long term through persisting effects on weight and metabolic health,” Dr Low says.

“This emphasises the importance of starting at the preconception and prenatal stages for most-effective intervention.”

During infancy, another factor comes into play: the age at which solid food is introduced.

Research shows introducing solid food before four months of age may increase the risk of gaining excess weight in childhood. Yet, the Growing Up in New Zealand study of 5770 infants found more than 40 percent started eating solid food by four months.

How food is eaten turns out to be important in older children too.

“For example, children served larger portions of food tend to consume more food. On the other hand, children whose caregivers strictly restrict the amount and type of food tend to eat in the absence of hunger in later childhood.”

Dr Low says given that childhood obesity-risk depends on the complex interaction of biological, developmental and socio-environmental factors, an exclusive focus on diet and exercise will do little to help.

“What is needed are policies to support preventive action through promoting preconception health of both biological parents and the mother’s health during pregnancy.

“This should be followed by informing parents and caregivers of appropriate feeding practices that support healthy growth and encourage good eating behaviours in the child.”

Dr Low urges those working to reduce childhood obesity to act with cultural sensitivity and mindfulness of parents’ financial, time and social-support constraints.