Individual differences in the use of pleasantness and palatability ratings

Previously we have suggested that individual subjects interpret the phrase "palatable food" in different ways. To test the consistency of the use of this term, 50 male volunteers consumed a simple lunch on two occasions, once with a more palatable food and once with a more bland version. Ratings of hunger, fullness, pleasantness and palatability were completed at the start and end of each meal. Overall, subjects ate slightly more of the palatable food. The difference in intake between conditions correlated with differences in pleasantness and palatability but not hunger at the start of eating. Rated pleasantness of the food declined between the start and end of the meal in most subjects, but changes in palatability were more variable, with a significant minority showing no change across the meal. Detailed analysis confirmed the existence of two populations of responses, one where pleasantness and palatability were synonymous, and one where palatability was rated as a constant property of a food. The existence of two interpretations of the term palatability in common English usage cautions against the use of this term as a reliable means of evaluating hedonic responses to foods in appetite studies.