A new study's highlighting there's more to obesity than making unhealthy choices.

A study of data gathered through the 'B4 School Check' programme between 2010 and 2016, shows 15.2 per cent of children were obese.

Of those, 11 per cent were European, 20 per cent Māori, and 33 per cent Pasifika.

Lead author Dr Nichola Shackleton says the number of Māori four-year-olds affected by obesity would halve if they experienced the same conditions as European children.

"The fact that Maori children have a higher obesity rate than European children is largely accounted for for the fact their families have a different
and they tend to live in more deprived areas."

She says that the children's family make-up and level of poverty accounts for half of the differences in obesity rates between Māori and European children.

"Differences between the ethnic groups are remaining really stable over time, so even though we are reducing obesity rates generally, we're not doing anything to reduce the inequities in those obesity rates."

Shackleton Mike Hosking understanding the cause is key to finding the solution.

"It's suggesting that actually there are wider issues going on here, and addressing these socio-economic difference between ethnic groups would have a large impact on a lot of difference child wellbeing outcomes."