New Zealand dietician criticises 'B4 School Check' for preschoolers

A New Zealand dietician has criticised the BMI (body mass index) check Kiwi children have before starting school, labelling it a flawed measure of health which can have harmful consequences. 

The B4 School Check, run by the Ministry of Health, is a nationwide programme offering a free checkup for four-year-olds. Carried out by a registered nurse, children will have their "general health and development" checked, including their height and weight. This is then used to calculate the child's BMI.

If a child's BMI means they're considered overweight, they're referred onwards for further treatment. 

But registered dietitian Lucy Carey believes the check may be doing more harm than good. 

In her new article 'Taking BMI off the Table', published in the New Zealand Medical Journal on Friday, she says BMI has been shown to be inaccurate, particularly for Pasifika, Māori and Asian children.

She says using it to label kids as overweight or obese may actually cause them to gain proportionally more weight over time. 

Carey quoted a 2012 study, which found parental concern about their child being overweight was related to restrictive feeding practices - and restriction is known to possibly produce additional weight gain.

Instead of individual treatment centred around weight loss, Carey says every family should have a conversation with a professional about healthy living.

"The limitations of BMI and the potential harm of labelling children as overweight and obese presents health professionals working at the coalface of childhood obesity with an opportunity," she writes. 

"Instead, a universal approach could be utilised. Every family, regardless of the size of their child, could have a conversation with the health professional about healthy living."

Carey says a better way to focus on health is for families to talk about the behaviours that might make a difference to health for everyone, including: "adequate sleep, restricting and monitoring screen time, cooking at home, eating meals together as a family, [and] encouraging child-led play". 

"This approach disregards size and focuses on wellbeing."

The BMI method of measuring health has come under fire in the past. A study done by Newshub last year showed 22 out of the 23-strong All Blacks squad were considered obese if using their BMI as a method of measurement.