Supplementary information files for Portions selected to stave off hunger are reduced when food is presented in an ‘unusual’ food-to-mealtime context: An implication for implicit satiety drivers

Supplementary files for article Portions selected to stave off hunger are reduced when food is presented in an ‘unusual’ food-to-mealtime context: An implication for implicit satiety drivers Research suggests that the role of expected satiety in influencing portion-size selection is reduced when food is presented in unusual food-to-mealtime contexts; however, the underlying mechanism has not been explored. Other research has revealed that different implicit satiety drivers (e.g., to stop momentary hunger or obtain complete fullness) are associated with different perceived levels of stomach fullness, portion-size selections and can change on instruction. The current study explored whether changes in expected satiety and ideal portions in congruous vs incongruous contexts can be explained by changes in implicit satiety drivers. Another aim was to investigate a previous exploratory finding suggesting that portions selected to stave off hunger are reduced when foods are presented in unusual food-to-mealtime contexts. At two trials (breakfast/lunch), participants (n = 40) selected a portion of typical lunch (pasta) and breakfast (porridge) foods via a psychophysical computer-based method 1) to stave off hunger for 5 h, and 2) as an ideal portion. Participants also indicated their perceived level of stomach fullness associated with 1) each portion, and 2) five implicit satiety drivers. Results revealed that a smaller average portion was selected to stave off hunger in incongruous (vs congruous) food-to-mealtime contexts (531 ± 229 vs 575 ± 236 kcal) (p = 0.008). This suggests that expected satiety is influenced by momentary context; foods are perceived to be more satiating when consumed in unusual (vs usual) contexts. Results also showed that implicit satiety drivers are malleable in regard to the portion size associated with a perceived level of stomach fullness and that this can vary contextually. These findings provide initial evidence to explain the psychological mechanism underlying the contextual differences observed in portion-size selections. Future work should explore longer-term impacts of consuming foods in unusual contexts.

本材料为论文《当食物以“非常规”餐食-用餐时段情境呈现时，为抵御饥饿而选择的餐量会减少：内隐饱腹感驱动因素（implicit satiety drivers）的启示》的补充资料。

已有研究表明，当食物以非常规餐食-用餐时段情境呈现时，预期饱腹感对餐量选择的调控作用会减弱，但目前尚未明确其潜在作用机制。另有研究发现，不同的内隐饱腹感驱动因素（例如，缓解瞬时饥饿或获得完全饱腹感）分别对应不同的主观胃充盈程度感知与餐量选择，且可通过指导语进行调节。

本研究旨在探究：在常规（匹配）与非常规（不匹配）情境下，预期饱腹感与理想餐量的变化是否可通过内隐饱腹感驱动因素的改变来解释。另一项研究目标为验证此前一项探索性发现：当食物以非常规餐食-用餐时段情境呈现时，为抵御饥饿而选择的餐量会减少。

本研究设置两次实验（分别在早餐、午餐时段开展），招募40名被试，通过基于计算机的心理物理学方法，让被试完成两项任务：1）选择可抵御5小时饥饿的餐量；2）选择理想餐量。所选食物均为典型的午餐品类（意面）与早餐品类（粥）。此外，被试还需报告与1）每份餐量、2）五种内隐饱腹感驱动因素相关的主观胃充盈程度感知。

结果显示，在非常规（相较于常规）餐食-用餐时段情境中，为抵御饥饿而选择的平均餐量更小（531 ± 229 千卡 vs 575 ± 236 千卡，p=0.008）。这表明预期饱腹感受瞬时情境影响：当食物在非常规（相较于常规）情境中食用时，其被感知的饱腹感更强。

研究还发现，内隐饱腹感驱动因素会随与主观胃充盈程度相关的餐量大小发生可塑性变化，且这种变化存在情境特异性。本研究结果为解释餐量选择的情境差异背后的心理机制提供了初步实证证据。未来研究可进一步探索在非常规情境中进食的长期影响。