Analysis of price changes and food purchases in obese and lean mothers

描述(申请人提供)：我们最近发现，对不太健康的(高卡路里营养)食品征税减少了能量摄入和购买的膳食脂肪，增加了蛋白质购买，同时补贴更健康的食品(低卡路里营养)增加了购买的能量，而购买的大量营养素的分布没有变化。该应用程序的目的是研究在225个种族和经济不同的成年人的大样本中，收入、身体质量指数(BMI)、食物的相对强化价值(RRV)和冲动是否缓和了价格对所购买的能量和大量营养素以及饮食质量的影响。参与者将完成五个购物环节，与以参考价格购物相比，选择的休闲食品是否被征收+12.5%和+25%的税，或者水果和蔬菜和无糖水的补贴是-12.5%和-25%是不同的。具体目标1将评估价格变化对所购买的能量和常量营养素的影响，预测税收将减少所购买的能量和膳食脂肪，并改善饮食质量，而补贴将增加水果和蔬菜以及所购买的能量。具体目标2将评估收入作为食品购买的调节因素，预测低收入家庭将对税收更加敏感，当这些食品被征税时，所购买的能量和脂肪的减少以及饮食质量的改善将比高收入家庭更大。我们预测，低收入家庭将对更健康食品的补贴做出更大反应。具体目标3将评估BMI作为食品购买的调节因素，预测BMI较高的参与者将对税收不那么敏感，当这些食品被征税时，所购买的能量和脂肪的减少较少，饮食质量的改善较大。体重指数较低的参与者将对购买更多水果和蔬菜的补贴做出更积极的反应。具体目标4将测试RRV作为食品购买的调节因素，预测RRV较低健康项目的RRV较大的参与者将对减少能量和脂肪购买和改善饮食质量的税收效果反应较差，相反，那些RRV较大的较健康食品的参与者将显示出购买的能量和脂肪减少，饮食质量改善，因为水果和蔬菜以及无糖水的补贴增加。具体目标5将评估冲动作为食品购买的调节因素，预测更冲动的参与者将对税收在减少能量和脂肪购买和改善饮食质量方面的影响反应较差，而当对休闲食品征税时，发现食物强化和冲动的参与者将表现出最小的能量和脂肪购买量的减少和饮食质量的改善。相反，那些不那么冲动的人在水果蔬菜和非甜水的价格得到补贴时，更有可能表现出购买水果和蔬菜或非甜水的增加。 公共卫生相关性：项目简介拟议的研究将评估收入、身体质量指数、食物的强化价值和行为冲动是否缓和了价格变化对能量摄入量、购买的大量营养素和饮食质量的影响。考察影响价格干预影响食品购买有效性的个体差异因素的效果，将有助于我们深入了解可以利用税收或补贴来影响人口健康的公共政策决策。

DESCRIPTION (provided by applicant): We recently found taxing less healthy (high calorie for nutrient) foods reduced energy intake and dietary fat purchased, and increased protein purchased, while subsidizing healthier foods (low calorie for nutrient) increased energy purchased with no change in distribution of macronutrients purchased. The goal of this application is to study whether income, body mass index (BMI), relative reinforcing value of food (RRV) and impulsivity moderate the effects of prices on energy and macronutrients purchased and diet quality in a large sample of 225 ethnically and economically diverse adults. Participants will complete five shopping sessions that vary whether selected snack foods are taxed by +12.5 and +25%, or fruits and vegetables and non- sweetened water are subsidized by -12.5% and -25% in comparison to shopping at reference prices. Specific Aim 1 will evaluate the effect of price changes on energy and macronutrients purchased, with the prediction that taxes will reduce energy and dietary fat purchased and improve diet quality, while subsidies will increase fruits and vegetables and energy purchased. Specific Aim 2 will assess income as a moderator of food purchases, with the prediction that lower income families will be more sensitive to taxes, and show greater reduction in energy and fat purchased and greater improvement in diet quality when these foods are taxed than higher income families. We predict that lower income families will be more responsive to subsidies for healthier foods. Specific Aim 3 will assess BMI as a moderator of food purchases, with the prediction that higher BMI participants will be less sensitive to taxes, and show less reduction in energy and fat purchased and greater improvement in diet quality when these foods are taxed than lower BMI participants. Lower BMI participants will be more responsive to subsidies in purchasing more fruits and vegetables. Specific Aim 4 will test RRV as a moderator of food purchases with the prediction that participants with greater RRV for less healthy items will be less responsive to effects of taxes on reducing energy and fat purchasing and improving diet quality, and conversely, those who have greater RRV for healthier foods will show a reduction in energy and fat purchased and improvement in diet quality as subsidies for fruits and vegetables and non-sweetened water are increased. Specific Aim 5 will assess impulsivity as a moderator of food purchases with the prediction that more impulsive participants will be less responsive to effects of taxes on reducing energy and fat purchasing and improving diet quality, and participants who find food reinforcing and are impulsive will show the smallest reductions in purchases of energy and fat and improvements in diet quality when snack foods are taxed. Conversely, those who are less impulsive will be more likely to show an increase in purchases of fruits and vegetables or non-sweetened water when the prices of fruits and vegetables and non-sweetened water are subsidized. PUBLIC HEALTH RELEVANCE: Project Narrative The proposed research will assess whether income, body mass index, the reinforcing value of food and behavioral impulsivity, moderate the influence of changing prices on energy intake, macronutrients purchased and diet quality. Examining the effects of individual difference factors that influence the effectiveness of price interventions to influence food purchasing will provide insight into public policy decisions that can use taxes or subsidies to influence population health.