Institute for Health Sciences, VU University Amsterdam, The Netherlands.
Eur J Public Health. 2010 Feb;20(1):65-9. doi: 10.1093/eurpub/ckp092. Epub 2009 Jul 8.
Large food portion sizes are determinants of a high caloric intake, especially if they have been made attractive through value size pricing (i.e. lower unit prices for large than for small portion sizes). The purpose of the two questionnaire studies that are reported in this article was to assess the impact of proportional pricing (i.e. removing beneficial prices for large sizes) on people's portion size choices of high caloric food and drink items.
Both studies employed an experimental design with a proportional pricing condition and a value size pricing condition. Study 1 was conducted in a fast food restaurant (N = 150) and study 2 in a worksite cafeteria (N = 141). Three different food products (i.e. soft drink, chicken nuggets in study 1 and a hot meal in study 2) with corresponding prices were displayed on pictures in the questionnaire. Outcome measures were consumers' intended portion size choices.
No main effects of pricing were found. However, confronted with proportional pricing a trend was found for overweight fast food restaurant visitors being more likely to choose small portion sizes of chicken nuggets (OR = 4.31, P = 0.07) and less likely to choose large soft drink sizes (OR = 0.07, P = 0.04).
Among a general public, proportional pricing did not reduce consumers' size choices. However, pricing strategies can help overweight and obese consumers selecting appropriate portion sizes of soft drink and high caloric snacks. More research in realistic settings with actual behaviour as outcome measure is required.
食物份量过大是高热量摄入的决定因素，尤其是如果这些食物通过超值份量定价（即大份量的单位价格低于小份量）变得更有吸引力。本文报告的两项问卷调查研究旨在评估比例定价（即取消大份量的优惠价格）对人们选择高热量食物和饮料份量的影响。
两项研究均采用实验设计，设有比例定价条件和超值份量定价条件。研究 1 在一家快餐店（N=150）进行，研究 2 在一家工作场所自助餐厅（N=141）进行。问卷中以图片形式展示了三种不同的食品（即软饮料、鸡块（研究 1）和热餐（研究 2））及其相应价格。主要观察指标为消费者的预期份量选择。
未发现定价的主要影响。然而，面对比例定价，快餐店超重访客更倾向于选择小份量的鸡块（OR=4.31，P=0.07）和不太可能选择大份量的软饮料（OR=0.07，P=0.04），这一趋势明显。
在一般公众中，比例定价并未减少消费者的份量选择。然而，定价策略可以帮助超重和肥胖消费者选择适当的软饮料和高热量零食份量。需要在实际行为作为结果测量的现实环境中进行更多的研究。
