Effects of Cookie Cues on Delay Discounting for Sucrose in Binge-Eating Prone Rats Exposed to a Restricted High-Sugar Diet

Acute and chronic consumption of sugar-rich foods alters the probability of binge eating and reinforcement processes related to self-regulation of food intake. While delay discounting—preference for smaller, more immediate outcomes over larger, delayed ones—is linked to binge eating in humans, the role of diet is less studied. We examined the extent to which acute food presentation (i.e., food cues) affected food delay discounting in binge-eating prone (BEP) rats exposed to chronic, though restricted, high-sugar diets. Female BEP and binge-eating resistant rats were randomly assigned to a chronic Oreo-plus-chow diet, where 22.5% of calories came from sugar, or a chow-only diet. Delay discounting for sucrose was assessed twice: first under baseline, then followed by an acute cookie-cue condition where rats consumed a morsel of Oreo cookie immediately before the second session. Cookie cues induced higher delay discounting compared to baseline for all rats. A significant binge-proneness × diet interaction was observed. Binge-eating prone rats with the chow-only diet exhibited higher delay discounting than BEP rats given the Oreo-plus-chow diet. These findings indicate that cookie cues increase delay discounting but also suggest that limited and consistent access to sugar may serve as a protective factor that decreases delay discounting in binge-prone organisms.

高糖食物的急性与长期摄入，会改变暴食行为发生概率，以及与食物摄入自我调控相关的强化过程。尽管延迟折扣（delay discounting）——即相较于更大但更延迟的奖励，更偏好更小且即时的奖励——在人类中已被证实与暴食行为相关，但饮食对此的影响机制尚未得到充分研究。本研究针对长期（但受限）暴露于高糖饮食的暴食易感（binge-eating prone, BEP）大鼠，探究了急性食物呈现（即食物线索）对其蔗糖延迟折扣行为的影响程度。研究将雌性暴食易感大鼠与暴食抵抗大鼠随机分为两组：一组长期摄入奥利奥加标准饲料饮食，其中22.5%的热量来源于糖分；另一组仅摄入标准饲料饮食。研究人员对大鼠的蔗糖延迟折扣行为进行了两次评估：首次为基线条件下的评估，第二次评估前，大鼠会先摄入一小块奥利奥饼干，以此构建急性饼干线索条件。相较于基线条件，所有大鼠在饼干线索条件下均表现出更高的延迟折扣水平。研究观察到显著的暴食易感性×饮食交互效应。仅摄入标准饲料的暴食易感大鼠，其延迟折扣水平高于饲喂奥利奥加标准饲料的暴食易感大鼠。本研究结果表明，饼干线索会提升延迟折扣水平，但同时也提示，有限且规律的糖分摄入，或许可作为一种保护因素，降低暴食易感个体的延迟折扣程度。