According to a new American study, healthy food makes consumers feel hungrier when choices are limited.
The research has appeared in the Journal of Consumer Research.
University of Chicago researchers Stacey Finkelstein and Ayelet Fishbach analyzed external controls in the domain of healthy eating - such as marketers who only offer shoppers healthy food samples or consumers who eat healthy meals in a restaurant that only offers healthy alternatives.
The authors write: "In the presence of external controls, people who eat healthily feel that they have made sufficient progress on their health goals.
"Then, they switch to the conflicting goal to satisfy their appetite: they express hunger and seek food."
In one experiment, the authors told people their job was to taste a food that was described as healthy or tasty (imposed conditions) or had people choose between the same food samples (free-choice conditions). Thereafter the volunteers rated their hunger.
The authors say: "People who were given a food sample described as healthy rated they were hungrier than those who were given the same sample framed as tasty and delicious.
"Those who freely chose the food sample were equally hungry. Thus, only those who were given the healthy food sample (imposed consumption) became hungrier."
In another study, participants were given a sample of the same piece of bread that was described as healthy (low-fat with lots of vitamins) or tasty (delicious with a thick crust and soft center). They also asked people how much they valued watching their weight.
The authors note: "People given the bread described as healthy were hungrier, thus they consumed more of an available snack, than those given the same piece described as tasty."
But the effect disappeared for those who valued watching their weight; they chose to eat the healthy bread.
The authors conclude: "When controlling agents take actions to help consumers meet their long-term objectives, people need to infer that they have made the choice to do so themselves. Otherwise, these efforts will backfire."