De Cock Nathalie, Vervoort Leentje, Kolsteren Patrick, Huybregts Lieven, Van Lippevelde Wendy, Vangeel Jolien, Notebaert Melissa, Beullens Kathleen, Goossens Lien, Maes Lea, Deforche Benedicte, Braet Caroline, Eggermont Steven, Van Camp John, Lachat Carl
1Department of Food Safety and Food Quality,Ghent University,Coupure Links 653,Ghent,Belgium.
2Department of Developmental, Personality and Social Psychology,Ghent University,Henri Dunantlaan 2,Ghent,Belgium.
Br J Nutr. 2017 Feb;117(4):611-620. doi: 10.1017/S0007114517000381.
Adolescents' snack choices could be altered by increasing the reinforcing value (RV) of healthy snacks compared with unhealthy snacks. This study assessed whether the RV of fruit increased by linking it to a reward and if this increased RV was comparable with the RV of unhealthy snacks alone. Moderation effects of sex, hunger, BMI z-scores and sensitivity to reward were also explored. The RV of snacks was assessed in a sample of 165 adolescents (15·1 (sd 1·5) years, 39·4 % boys and 17·4 % overweight) using a computerised food reinforcement task. Adolescents obtained points for snacks through mouse clicks (responses) following progressive ratio schedules of increasing response requirements. Participants were (computer) randomised to three experimental groups (1:1:1): fruit (n 53), fruit+reward (n 60) or unhealthy snacks (n 69). The RV was evaluated as total number of responses and breakpoint (schedule of terminating food reinforcement task). Multilevel regression analyses (total number of responses) and Cox's proportional hazard regression models (breakpoint) were used. The total number of responses made were not different between fruit+reward and fruit (b -473; 95 % CI -1152, 205, P=0·17) or unhealthy snacks (b410; 95 % CI -222, 1043, P=0·20). The breakpoint was slightly higher for fruit than fruit+reward (HR 1·34; 95 % CI 1·00, 1·79, P=0·050), whereas no difference between unhealthy snacks and fruit+reward (HR 0·86; 95 % CI 0·62, 1·18, P=0·34) was observed. No indication of moderation was found. Offering rewards slightly increases the RV of fruit and may be a promising strategy to increase healthy food choices. Future studies should however, explore if other rewards, could reach larger effect sizes.
与不健康零食相比，增加健康零食的强化值（RV）可能会改变青少年的零食选择。本研究评估了将水果与奖励联系起来是否会增加水果的强化值，以及这种增加的强化值是否与单独的不健康零食的强化值相当。还探讨了性别、饥饿程度、BMI z评分和奖励敏感性的调节作用。使用计算机化食物强化任务，在165名青少年（年龄15.1（标准差1.5）岁，39.4%为男孩，17.4%超重）的样本中评估了零食的强化值。青少年通过按照反应要求递增的累进比率时间表点击鼠标（反应）来获得零食积分。参与者被（计算机）随机分为三个实验组（1:1:1）：水果组（n = 53）、水果+奖励组（n = 60）或不健康零食组（n = 69）。强化值通过反应总数和断点（终止食物强化任务的时间表）来评估。使用了多水平回归分析（反应总数）和Cox比例风险回归模型（断点）。水果+奖励组和水果组之间的反应总数没有差异（b = -473；95%置信区间-1152，205，P = 0.17），与不健康零食组之间也没有差异（b = 410；95%置信区间-222，1043，P = 0.20）。水果组的断点略高于水果+奖励组（风险比1.34；95%置信区间1.00，1.79，P = 0.050），而不健康零食组和水果+奖励组之间未观察到差异（风险比0.86；95%置信区间0.62，1.18，P = 0.34）。未发现调节作用的迹象。提供奖励会略微增加水果的强化值，可能是增加健康食物选择的一种有前景的策略。然而，未来的研究应该探索其他奖励是否能达到更大的效应量。
