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"Our body is not good at telling us when we’ve had enough food."

It’s a discouraging statistic that Australia has one of the highest rates of obesity in the world.

With literally too much on our plates, the number of overweight and obese Australians is now looming as the single largest threat to public health.

Over the past decade, this has generated a significant amount of health and nutrition research but it’s only recently that studies from a marketing and social management perspective have emerged to tackle the problem.

Professor Chris Dubelaar is Associate Dean (Research Development) at Deakin Business School and for the past six years, he’s investigated the influence of portions, packaging and social settings on food consumption.

He says that alongside the endless product choices and swirl of supersized marketing, there’s a simple reason for our nation’s ballooning weight.

‘Our body is not good at telling us when we’ve had enough food. Basically it evolved in times when food was scarce, so if you can eat more then go for it, because tomorrow you may be hungry! That’s also why we’re so good at storing fat.’

Professor Dubelaar – a former electrical engineer – says his research came about ‘serendipitously’ after colleagues at Queensland’s Bond University (where he was Professor of Marketing) asked him to help build a statistical model for a food portions study.

‘Initially, I was drawn to the research by the challenge of designing a statistical model that would explore how relationships (with food) work. But it’s an intrinsically interesting area on its own.  The models are still fun to do, but the work is so much more than just the statistical challenges,’ he says.

He explains that one of the reasons we’re eating more is simply because portions, plates and packages are larger. Yet we hardly notice it.

‘We think we’ve eaten the same amount as when we’ve eaten less from a smaller size serving … so when this persists, we gain weight without realising why or how.’

Working with a team of researchers from Bond University and the Grenoble Ecole de Management in France, Professor Dubelaar says one of the aspects he enjoys most about the research is its ability to surprise.

‘For example, when we began looking at portion sizes, no-one had previously calculated the exact effect from doubling the sizes – we were astonished at how large the effect was. And each time we work on a new area, we continue to be astonished at what we uncover.  We also found that when respondents knew (or believed) they were being watched, the effects of plate size on consumption disappeared.’

It seems that within a social setting we are more careful – or mindful – about how much we eat. But when alone, we eat more and so the effects of plate size on consumption are much greater.

Professor Dubelaar says it’s interesting to observe the role that ‘mindfulness’ has on eating. It’s also one of the challenges of accurate data collection.

‘You’d think giving people free food would make it easy, but we cannot reveal that the study is about food or it triggers mindfulness – and that leads to a distortion in the responses,’ he explains.

So in the quest for accuracy, the researchers carefully disguise the data collection process so that food consumption appears to be an incidental – rather than a central – part of the investigation.

‘For example, we often work with someone collecting data for another purpose (perhaps a study on advertising effectiveness) and while the respondents are completing that task, we give them a variety of snacks and then observe how much is eaten after a fixed amount of time,’ he explains.

In 2014, the Journal of Marketing published their work on the effect of portion size on consumption and the Journal of the Association for Consumer Research is set to publish their work on the effects of plate, bowl and package sizes on consumption early in 2016.

He says the research highlights the impact that business and marketing decisions have on public health.

‘Businesses often take the position that their products are not the source of social ills – such as obesity. However demonstrating there is a link between how food products are offered, and how they are consumed, exposes all players to the importance of understanding the underlying consumption decision processes.’

Professor Dubelaar says it’s also important for consumers to understand that they’re often not in complete control of their eating patterns. 

‘Specifically, our senses are not linear - they work in a logarithmic fashion.  This means that when a portion size increases, we don’t see that increase for what it is, but for considerably less than it is.  So we tend to eat more than we should from larger portions. But knowing this allows us to be better informed and to also have a better mechanism through which to control our consumption patterns and thus, their effects on our health and well-being.’

Teaching units in applied marketing and research methods, Professor Dubelaar says his research plays a valuable role in the classroom.

‘It demonstrates the interplay between social benefits, personal choice and business profits – and this often sparks intense critical reflection about the role of businesses in society and how to balance it with the role of both individuals and government.’

With his co-researchers, Professor Dubelaar is working on a number of projects around the effects of portion sizes, mindfulness, social guilt and the perception of serving sizes. 

‘Deakin is fabulous place to be curious,’ he says. ‘The culture rewards curiosity and encourages exploration.’

For more information on this topic, you can contact Professor Dubelaar directly via c.dubelaar@deakin.edu.au or +61 3 92443786.