Short- and long-term effects of changes in pleasantness on food intake

This study concerns the effects of pleasantness on ad libitum food intake, liking and appetite over 5 successive days. Pleasantness was manipulated by varying the salt level in bread. Thirty-five students consumed ad libitum sandwiches for lunch, made with bread individually perceived as low, medium or high in pleasantness, in a balanced cross-over design. Pleasantness and desire-to-eat the sandwich were rated at first bite, after the consumption of each sandwich and at the end of the lunch. Fullness was rated just befo re and at several intervals after lunch. On the first day, the students ate less of the least pleasant bread than of the medium and most pleasant brea d. On the fifth day, however, consumption of all breads was similar. For th e least pleasant bread, energy intake at lunch, desire-to-eat and fullness, all increased over days, whereas these variables remained constant for the medium and most pleasant bread. Mean pleasantness ratings for all breads r emained unaltered across the days. We conclude that, with repeated exposure , the desire-to-eat, fullness and intake of a less preferred food can incre ase over time. Thus, the relationship between pleasantness and food intake changes over this period. (C) 2000 Academic Press.