While it was previously believed that consumers overeat healthy food because they underestimate its calorie content, the findings of US researchers, led by Jacob Suher of the University of Texas at Austin, suggest it is due to the implicitly-held belief that healthy food is less filling – even when the calorie content is clearly displayed.
The findings are particularly relevant given the increasing prevalence of foods marketed as being healthy, according to the researchers.
“Our research suggests that the influx of health information may ironically abet the obesity epidemic,” they wrote.
“While it is preferable for people to choose healthy food over unhealthy food, if people tend to over-consume foods labelled as healthy then the proliferation of health foods and nutrition labels could actually lead to an increase in calorie intake. Accordingly, the effects of this phenomenon would be especially detrimental if unhealthy foods are portrayed as healthy.”
They cited the example of US food service chain Chipotle which claims to be healthy by using natural ingredients when in fact its burritos can contain up to 1000 calories.
Satisfaction through satiation
In order to counter this misconception – and prevent consumers from buying and eating more than they need – food manufacturers should emphasise the nourishing qualities of their products rather than the healthiness.
This works because it acts on another implicitly-held belief, namely that 'nourishing', 'wholesome' or 'strengthening' food contains the necessary ingredients and nutrients required for maintaining and improving physical and mental health.
But why would food companies want to use a marketing strategy that implicitly encourages consumers to buy less of a product, and not more?
There are clear benefits according to Suher, who said consumers are more likely to make positive brand evaluations and increase brand loyalty after eating ‘nourishing’ food that fills them up.
“The research finds that consumers perceive foods labelled as nourishing as both healthy and filling. This is a positive combination of attributes that may increase market share and provide an opportunity to charge a premium price,” he told FoodNavigator, adding that some companies providing food portions at a flat fee – such as airplane, restaurant or buffet food – could even consider reducing portion sizes which would help them to manage food costs.
A nourishing claim could come in the form of added vitamins, he said.
“To the extent that vitamins are associated with physical and mental well-being this may increase perceptions of nourishment, however future research is needed to know for certain.”
The study
The researchers conducted three separate experiments. In the first, 50 university students were asked to categorise pictures of healthy and unhealthy foods with words associated with satiation, such as heavy or strengthening, or non-satiation such as light or weakening.
Reaction times were faster when unhealthy foods were categorised with satiating words than for healthy and non-satiating. However, they were faster when healthy foods were paired with nourishment words than for unhealthy foods and nourishment words, revealing the extent of this implicit association.
A second experiment assessed how the healthy portrayal of a food affected the hunger levels of 40 subjects after actual consumption. Subjects were given either a healthy cookie high in protein, fibre and vitamins or one high in fat and sugar, with those in the healthy cookie group reporting greater hunger levels.
Finally in the third leg, the researchers assessed whether the ‘healthy = less filling’ intuition could be lessened by emphasising the nourishing qualities for popcorn. They found that subjects ordered smaller portion sizes and ate less popcorn when it was portrayed as nourishing as opposed to healthy.
"This provides evidence that making the nourishing association of healthy food salient mitigates the tendency to order and consume more of a food when it is portrayed as healthy (vs. unhealthy)," wrote the researchers.
Source: Journal of the Association for Consumer Research
Due to be published online, Vol. 1, issue 1, 15 January 2016
“Eating Healthy or Feeling Empty? How the “Healthy = Less Filling” Intuition Influences Satiety”
Authors: Jacob Suher, Raj Raghunathan and Wayne D. Hoyer