The second study illustrated the same effects, but on adult students. Four portions of gummy candies were displayed. The participants were told the size of the first portion and were then asked to estimate the rest. But there were also two different conditions leading to starkly different findings by manipulating the perceptions of the desirability and healthiness of the candies. In an “unhealthy” condition, the candies were labeled as “gummy candies”, while in the healthy condition, they were labeled as “nutrition chews with Omega 3 and vitamins.” There was also a high and low desire manipulation where participants were either given a candy to taste before making the size estimates or not.
By simultaneously boosting the desire to eat the food by giving a sample and enhancing its unhealthiness perception using labeling, portion size estimates grew by 19 percent.
The researchers then tested their theory on 116 adults at a sports centre, operating on a hypothesis that “restrained eaters” or those with strict diets would be especially conflicted towards food due to two different goals: enjoying tasty food and pursuing a healthy diet. Dieters should therefore be even better placed to estimate increased portion sizes of unhealthy foods. This proved to be the case, with size estimates 53 percent higher among those highly ambivalent, i.e. the dieters.