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The dangers of supersized servings of junk food such as hot chips, fizzy drink or ice cream are well known – the larger the portion the more we eat. Now new research reveals we can also harness this effect for good, and increase our consumption of healthier foods.
In two experiments, researchers from Australia and France found that doubling portion sizes of a healthy snack given to teenagers and young adults significantly increased the amount of healthy food they ate.
“Eating plenty of fruit and vegetables helps reduce the risk of diseases such as heart disease and cancer, but most Australians do not come close to the recommended daily intake,” says co-author Associate Professor Natalina Zlatevska from the University of Technology Sydney.
Dr Zlatevska’s research focuses on how marketers can play a positive role in encouraging consumers towards healthy decisions through factors such as packaging, portion size and nutritional information.
“I’ve always been interested in self-regulation – partly because I am truly terrible at it, despite best intentions,” Dr Zlatevska says. “I’m interested in exploring how marketing influences our ability to control our behaviour.”
The study, Might bigger portions of healthier snack food help?, was published in the latest issue of the journal Food Quality and Preference.
The first experiment involved 153 university students in France who were given small or large servings of healthy apple chips or unhealthy potato chips in a laboratory setting to eliminate potential social influences.
While the students generally ate fewer apple chips than potato chips, those given a larger packet still ate more, regardless of whether the snack was healthy or unhealthy.
For the second study, 77 high school students attending a film festival were given a small or large serve of baby carrots as a snack. The students watched either a film about a restaurant that included many eating scenes or a romantic comedy with no food-focused content.
While carrots might seem like an unappealing movie snack, the teens still ate them, and the larger the serve the more they ate, but the effect was also influenced by movie content. The food-related film viewers ate less than the romantic comedy viewers.
Co-author Professor Chris Dubelaar from Deakin University says the study findings present interesting insights into the potential for manipulating portion size as a way to increase healthy eating.
"Previous studies have found that people will eat more unhealthy food when presented with a large portion size," he said.
"The results of our current study tell us this portion size effect also holds true with healthy foods, which opens up the potential for adjusting portion size when trying to encourage healthier eating habits.
"For example, parents trying to get their children to eat more veggies could serve up larger portions. This would also work for healthy snacks such as fruit or any food you want someone to eat more of."
Professor Dubelaar said it was particularly interesting to find that during the food-oriented film, all participants ate the same amount of food from both the large and the small portions.
"This tells us that our food environment has an even larger impact on our consumption than we thought," he said.
The study was conducted by researchers at the University of Technology Sydney, Deakin University, the Grenoble Ecole de Management, and Macquarie Graduate School of Management.