Behaviour and Health Research Unit, Institute of Public Health, Forvie Site, University of Cambridge School of Clinical Medicine, Box 113 Cambridge Biomedical Campus, Cambridge, CB2 0SR, United Kingdom.
Behaviour and Health Research Unit, Institute of Public Health, Forvie Site, University of Cambridge School of Clinical Medicine, Box 113 Cambridge Biomedical Campus, Cambridge, CB2 0SR, United Kingdom.
Appetite. 2019 Feb 1;133:147-155. doi: 10.1016/j.appet.2018.10.021. Epub 2018 Oct 24.
Placing food further away from people decreases likelihood of consumption ("Proximity Effect"). However, it is unclear how proximity affects consumption when both healthier and less healthy foods are available and cognitive resource for self-control is limited.
To test the hypothesis that when both healthier (raisins) and less healthy (chocolate M&Ms) foods are available, placing less healthy food far, rather than near, increases the likelihood that healthier food is consumed.
General population participants (N = 248) were all put under cognitive load and randomised to one of four groups: 1. Raisins near (20 cm), M&Ms far (70 cm); 2. Both foods near; 3. M&Ms near, raisins far; 4. Both far.
proportions of participants consuming raisins and M&Ms, respectively.
The results did not support the primary hypothesis: when healthier and less healthy foods were both available, placing M&Ms far, rather than near, did not increase likelihood of consuming raisins (OR = 1.54, p = .432). Regardless of the M&Ms proximity, likelihood of consuming raisins was unaffected by the raisins' proximity (62.9%(near) vs. 56.5%(far) OR = 0.61, p = .211). Likelihood of consuming M&Ms non-significantly decreased when they were far and raisins were near, and when both foods were far (OR = 2.83, p = .057). Likelihood of consuming M&Ms was affected by M&Ms proximity, being higher when near (68.3%) than far (55.6%), OR = 0.39, p = .015. Indices of cognitive load impact (higher vs lower) were unrelated to consumption of either food.
Likelihood of consuming a healthier food was unaffected by its proximity and that of a less healthy food. By contrast, likelihood of consuming a less healthy food was influenced by its proximity and possibly by that of a healthier food. These effects need replication in studies designed to detect smaller effect sizes.
This study was registered online with ISRCTN (ISRCTN11740813).
将食物放在远离人的地方会降低人们食用的可能性（“接近效应”）。然而，当有更健康和不太健康的食物可供选择且自我控制的认知资源有限时，接近程度如何影响消费尚不清楚。
检验以下假设，即在有更健康的（葡萄干）和不太健康的（巧克力 M&M 豆）食物可供选择的情况下，将不太健康的食物放在远处而不是近处会增加食用更健康食物的可能性。
将普通人群参与者（N=248）置于认知负荷下，并随机分为四组之一：1. 葡萄干放在近处（20 厘米），M&M 豆放在远处（70 厘米）；2. 两种食物都放在近处；3. M&M 豆放在近处，葡萄干放在远处；4. 两种食物都放在远处。
分别食用葡萄干和 M&M 豆的参与者比例。
结果并未支持主要假设：当有更健康和不太健康的食物可供选择时，将 M&M 豆放在远处而不是近处并不能增加食用葡萄干的可能性（OR=1.54，p=0.432）。无论 M&M 豆的远近如何，葡萄干的远近都不会影响食用葡萄干的可能性（62.9%（近处）与 56.5%（远处）OR=0.61，p=0.211）。当 M&M 豆放在远处而葡萄干放在近处，以及当两种食物都放在远处时，食用 M&M 豆的可能性非显著降低（OR=2.83，p=0.057）。食用 M&M 豆的可能性受 M&M 豆的远近影响，当 M&M 豆放在近处时（68.3%）高于远处（55.6%），OR=0.39，p=0.015。认知负荷影响指数（较高与较低）与两种食物的食用均无关。
食用更健康食物的可能性不受其远近的影响，而食用不太健康食物的可能性则受其远近的影响。相比之下，不太健康食物的食用可能性受其远近的影响，且可能受更健康食物远近的影响。这些效应需要在设计用于检测较小效应量的研究中进行复制。
本研究在 ISRCTN 网站（ISRCTN86066066）进行了在线注册。
