A noteworthy study of Alexander Chernev in the Journal of Consumer Psychology (April 2011 issue) showed that people have misguided beliefs about the relationship between a meal healthiness and its impact on weight gain. Simply said; they believe that adding a healthy item (such as an apple or salad) to a meal magically decreases the number of calories in a meal.
The reason is that people tend to categorize foods as healty and unhealthy ones. Particularly dieters are more likely to believe in 'negative calories'.
This is not the first study on the so-called health halos. Health halos are associations that people have with certain foods or restaurants. Brian Wansink and Pierre Chandon found that there's a health halo around foods at restaurants like Subway that leads people to overeat on side dishes and grossly underestimate the number of calories they consume. Even organic foods have a health halo, as people believe they have fewer calories (according to a recent study of Schuldt and Schwarz).
Not so good news. At least, not for people who want to manage their weight and eat healthy. Good news for restaurants. Just simply add a salad to your meal or menu and everything looks more wholesome. Not surprising that most (fast food) restaurants already discovered this without doing any consumer research.
According to Chernev at his interesting blog: 'The focus of current public policy campaigns needs to shift away from the stereotypes associated with “good” and “bad” foods and toward the quantity of food consumed.' I agree completely. And stop dieting: it poisons your mind with this kind of misbeliefs!