New Australian body size data study predicts 3kg – we need to design for it

iMOVE Cooperative Research Centre

Australia’s frst anthropometry dataset has revealed we are stacking on about 3kg every ten years –with big implications for transport design, including how big airline seats should be.

Anthropometry is the study of measuring human body sizes and shapes.

The ground-breaking study conducted by academics at the University of South Australia for partners Transport for NSW (TfNSW) and Department of Transport and Planning Victoria and funded by the iMOVE Cooperative Research

Centre has produced a comprehensive anthropometric dataset for Australian adults aged 18-64 – the frst time this has been done for the Australian population.

In developed countries, obesity and weight gain have risen among adults since the 1960s and children since the 1980s. For Australia, the new dataset suggests a continuing increase in weight for adults of between 1.5 and 3.5kg per decade.

“Overall, a likely scenario for Australia over the next 20 years is: no increase in stature, and a 2 to 3kg increase in weight per decade. A conservative scenario, which would lead to more accommodating designs, is an increase in stature of 10mm per decade, and an increase in weight of 3kg per decade,” the university researchers said in their fnal report released this week.

The researchers noted the relationship between bigger body sizes and airline seats, citing studies that found “changes in body shape dimensions over the past 30 years have rendered airline seating dimensions to be problematic, and unable to accommodate up to 68% of males and 22% of females”.

Historically, commercial airline seating was based on average passenger weight data from the 1950s to 1970s. But as the modern traveller becomes signifcantly heavier, airlines are facing challenges in accommodating an increasingly larger passenger base.

The weight gain trend has serious implications for aircraft design and fuel effciency. Heavier planes require more fuel, which in turn drives up operational costs and environmental concerns. The issue has gathered signifcant media interest in recent weeks with US fnancial analysts saying United Airlines would save USD $80m a year if the average passenger lost about 4.5kg.

What about trains, buses, and other forms of transport?

The researchers said the new dataset can help industry deal with these issues. “Anticipating the changes in body size over decades is important if one wants to ensure that a design, equipment, or layout will remain ft for use by the intended users over its entire life span,” they said.

Ian Christensen, Managing Director of iMOVE CRC, commented on the study’s fndings:

“This research is not just about numbers on a scale. It’s about understanding the evolving needs of our population and ensuring our transport systems, both on the ground and in the air, are equipped to serve everyone comfortably and safely with human-centred design.

“The data from this study provides a roadmap for the future. It’s an opportunity for designers, policymakers, and industry leaders to come together and create transport solutions that are inclusive, sustainable, and forward-thinking.”

Christina Kirsch, Senior Human Factors Specialist at TfNSW,

said:

“Our objective is to gain data specifc to the Australian population so we can design public transport that caters specifcally to our shapes and sizes.

“These designs directly impact passenger comfort, safety, accessibility, and overall user experience. By incorporating anthropometric data into the design process, we can ensure that work and transport systems are more effcient, safe, and comfortable to use by our staff and customers.”