July 26, 2018


Weighing kids at school has more pros than cons but the reasons may surprise you.

Tim Olds, University of South Australia

A Deakin University proposal to measure the height and weight of all Australian school children has understandably generated controversy. Some commentators have labelled it misguided, fearing it could encourage kids to “pursue weight loss at any cost”.

While there are benefits and downsides of measuring kids’ height and weight at school, the pros outweigh the cons.

But some reports have confused the purpose of the scheme, which is intended to generate data to inform obesity research and policy responses, rather than provide feedback on the individual child’s health status.

Let’s start at the beginning at look at the difference between screening and surveillance, and what the Deakin team has proposed.

BMI report cards

Screening programs weigh kids to identify those who are at risk of health problems associated with their fatness. This is generally based on BMI (body mass index), which measures weight in relation to height. The results of the screening – “BMI report cards” – are sent to parents, and sometimes to the kids and schools as well.

Read more:
Does my BMI look big in this? And does it really matter?

Screening programs are rare in Australia, but are widely used in several US states, notably Arkansas and California.

The logic behind screening is that obesity is a health issue like ADHD or movement disorders, and schools have a duty of care to report these conditions to parents. There is strong evidence that parents are not very good at identifying the weight status of their children.

Screening programs are controversial. In the US, they are generally well-received by parents, who claim to take action if their child is identified as overweight.

But there is growing evidence that these programs are ineffective.

Collecting data for research

The Deakin group is not recommending BMI screening or BMI report cards. They are arguing for a system of surveillance, which is quite different.

Surveillance is the systematic collection and analysis of data on kids’ fatness from a representative sample, or from a census.

For surveillance purposes, neither children, nor the teachers, nor the parents are told the child’s BMI. Children may be identified by coded numbers which are known only to the researchers.

The Deakin proposal doesn’t include reporting on the child’s BMI to parents, teachers, or students themselves.
Belinda Pretorius/Shutterstock

Parents can opt out by ticking a box, and no measurement can be made without the verbal assent of the child.

Measurements are done by trained clinicians, in private.

No child, parent or teacher is made aware of any measurement, and any questions about the results are defused by comments such as:

Kids of your age come in all shapes and sizes, and anyway, they change so quickly. If you’re worried, why not ask your mum or dad to measure you?

These procedures are now standard practice in research settings.

Downsides of weigh-ins

The biggest concern is that overweight (or underweight) kids may feel sensitised to weight issues, and may adopt unhealthy weight management practices like purging or extreme dieting.

Read more:
Health Check: should you weigh yourself regularly?

A review of the Arkansas program found that 7% of kids were embarrassed about being weighed at school. It is likely that some kids will be distressed by the procedure.

In one discussion forum, a mum said:

I experienced eating disorders in high school and if I knew there were weigh-ins (even occasionally) it’d send me into a near-constant state of panic and restricting and purging.

Other kids may find the “normalisation” of weighing reassuring.

The Arkansas review found that kids were not more likely to be teased about their weight, or go on diets, or have more concerns about body image after the introduction of the measurement program.

Some people feel that obesity is not a disease, that kids can be healthy at any weight, and that we should be focusing on behaviours such as healthy eating and physical activity, not fatness.

However, there is a strong association between fatness a wide range of diseases, notably diabetes, and pretty powerful genetic and experimental evidence that the relationship is causal.

So what are the benefits?

The main benefit is that BMI surveillance will provide a rich source of accurate data.

At the moment, we only collect data on samples of kids who put up their hands to be measured. As you would expect, fatter kids are less likely to do this, so our data underestimate, and by a pretty large margin, how many kids are overweight or obese.

In one study, an opt-in method estimated obesity prevalence at 10%. The opt-out method estimated 14%.

Some find weigh-ins traumatising, while others find the normalisation of it reassuring.

Having regular, opt-out, population-level surveys of kids’ height and weight allows us to chart historical trends, geographical distributions, and, if measurements can be linked to de-identified personal data, associations with socioeconomic status, environments, and health outcomes.

All this helps to direct resources where they are needed, and to plan more effective interventions.

Read more:
The real reasons why parents struggle with children’s portion sizes

The potential uses of data of this sort are enormous. Here are two examples.

Some recent studies have linked obesity to air pollution. By looking at the associations between where kids live, their exposure to pollution, and fatness, we can test this theory.

The ConversationAnother recent study in the US found that the entire increase in children’s fatness in the first three years of primary school occurred during the summer holiday period. By weighing kids at the start and end of each school year, we could see if the same thing is happening in Australia.

Tim Olds, Professor of Health Sciences, University of South Australia

This article was originally published on The Conversation. Read the original article.

Find out what MoM’s think of the proposed school weigh-in HERE.

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  • Shocking idea that I dont agree with at all.


  • BMI is NOT always accurate. We had health checks and flu vaccinations. One lady was quite tall and very slim. You could actually see some of her bones as she had been very sick only couple of weeks before. Based on the details taken they reckoned her BMI was high.
    One advantage is many parents never check their child’s weight. Some don’t notice any difference because they are with them every day. A drop in weight can indicate a medical problem which needs further tests and possibly intensive treatment.


  • I don’t think it is appropriate to do it at school.

    • I agree – it is all about the right place and the right time and the right professional.


  • How is the data useful when not compared with home life, lifestyle, name, area, or anything else that would be absolutely relevant in data collection – I would have thought! What about the child that has a can of Pepsi before school shared amongst he and his 3 siblings because his parents are too out of it to feed the children. This eldest child is also responsible for getting all 4 of them ready for school in whatever clothes are available. How does this story fit the data and the narrative for collection for obesity?


  • I still don’t think this should be done at school. Kids have enough stress about their school work.


  • The article states that it is used in the US where obesity is a massive problem. And it is effective????


  • If the weigh in study was associated with bullying it would be accepted by every child and their parent. Bullies are always ‘big fat kids’ aren’t they, like we see in the Ginger Meggs comics. Or are the parents worried that this weigh in at the start of the school year and at the end of it will prove that the parents are to blame for indulging their children over the school holidays and that’s why they have gained weight. I would have loved something like this – my kids must have lost weight over the school holidays, they were hardly ever at home to eat as they were enjoying themselves playing with all the other kids around the area.


  • See, in my opinion, that’s what doctors are for. Not schools! Maybe at a stretch (and I mean a long stretch) in PDHPE….our doctor had a nurse that takes each patient in before seeing the doctor and weighs and measures height etc, for kids and adults. I think that’s a good system, by again, it’s for the GP and not the school!


  • School is not the place to have our kids weighed. When it’s just for research they should find their own victims ;) and not approach schools.


  • still opting kiddo out should they bring it in


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