Manipulating food prices is one of the most powerful ways to modify food purchasing. An alternative approach is by point of purchase nutrition information using nutrient profiling. The goal of this grant is to assess the independent and combined effects of 1) 25% taxes and subsidies on the least and most nutritious foods based on their nutrient profiles and 2) point of purchase nutrient profiling on nutrient density, energy, energy density and specific nutrients of foods purchased. The study will be undertaken in a sample of ethnically and income diverse adults who do the food shopping for their families. A 2 x 2 factorial design will be used to randomize 800 shoppers to 1) a control arm with usual nutrition information, 2) nutrient profiling information only on all foods in the grocery store, 3) taxes on the 20% lowest nutritional value foods plus subsidies on the 20% highest nutritional value foods only, and 4) nutrient profiling plus the differential taxes and subsidies. Nutrient profiling will be based on NuVal, a comprehensive nutrient profiling system that scores foods on a 1-100 scale based on an algorithm that takes in to account positive (fiber, vitamins, minerals, Omega 3 fatty acids, etc.) and negative aspects of food (trans fat, salt, sugar, etc,) as well as factors such as protein and fat quality, energy density, and glycemic load. NuVal scores predict health outcomes, including all-cause mortality, in a cohort study of 100,000 people, with higher scores (better nutritional value) associated with lower risk for a variety of diseases. Specific Ai 1 will assess the main and interactive effects of point of purchase nutrient profiling and price changes on average nutrient density/100 kcal of all foods purchased, and Specific Aim 1a will assess the main and interactive effects of nutrient profiling and/or price changes on total energy and energy density of foods purchased, average NuVal scores and average values of specific nutrients including fiber, added sugar, saturated fat and sodium, and the main and interactive effects on average NuVal scores and macronutrient composition of purchased foods.
Specific Aim 2 will assess the main and interactive effects of nutrient profiling and/or price changes on cost to improve nutrient density/100 kcal.
Specific Aim 3 will assess the whether income, body mass index or dietary restraint moderate the effect of nutrient profiling and price changes on nutrient density/100 kcal.
The proposed research will assess the independent and combined influence of price changes and/or point of purchase nutrient profiling on a broad array of nutritional measures of food purchased using an innovative online experimental grocery store. Examining the effects of pricing changes and nutrient profiling on nutritional quality of foods purchased will provide experimental data to inform public policy decisions about two factors that are often considered as ways to improve public health.