News release

From: University of Technology Sydney (UTS)

How you feel about fast-food brands can predict overall diet quality

A fondness for well-known fast-food and sugar-sweetened beverage brands may be a strong warning sign of a poor overall diet, even among those who rate these brands as unhealthy, a new study suggests.

A bad diet can fuel obesity, type 2 diabetes, heart disease and some cancers – and increase the risk of premature death. Aggressive marketing of fast-food brands may be helping drive this increase in chronic diet-related diseases.

"When people develop a psychological loyalty to fast-food brands, it acts as a strong predictor of their saturated fat and sugar intake – regardless of how healthy they perceive these brands to be," said senior author Dr Poppy Watson from the University of Technology Sydney (UTS).

While it’s tempting to think the occasional fast-food treat doesn’t reflect the rest of your diet, the research found that participants who liked fast-food brands not only consumed more fat and sugar but also tended to perceive those brands as healthier.

"Those who love these brands actually rate them as healthier. Nutritional knowledge plays a role, but the strongest predictor of health ratings is how much they like the brand," said senior author Dr Mike Kendig, a senior lecturer in Medical Science at UTS.

The research findings, recently published in the Journal of Health Communication, suggest repeated exposure to branding can build familiarity and positive feelings that spill over into health perceptions and dietary choices.

The study involved researchers from medical science, psychology and marketing, including Professor Natalina Zlatevska and Associate Professor Adrian Camilleri from UTS Business School.

Researchers assessed attitudes and perceived healthiness of fast-food and beverage brands, along with a comprehensive dietary questionnaire, in two separate studies in adults in Australia and the US.

"Unhealthy food marketing is pervasive in retail, media, sport and other settings. Companies wouldn’t do this if it wasn’t incredibly effective in shaping purchase decisions. It’s self-evident that it works, but we, as the consumer, are not always cognisant of that," Dr Watson said.

One-third of calories consumed by adults in Australia and the US come from “discretionary” foods and drinks – ultra-processed, energy-dense products loaded with sugar, salt and saturated fat, such as chips, burgers and ice-cream.

"We need to be aware of how much marketing biases our health perceptions and influences what we eat. But there’s also a broader responsibility to rein in some of this marketing, because the evidence shows that it’s shaping diets at a population level," Dr Watson said.

"Governments and public health organisations invest heavily in nutrition education on the assumption that knowledge helps people to make healthier choices. Our research suggests the picture is more complicated."

An emotional attachment to your favourite fast-food brand could be shaping what ends up on your plate, despite nutrition warnings. The findings support calls for greater restrictions on junk-food advertising and other government policies aimed at reducing the grip of fast-food giants.