Clinical trial NCT04654780: Study of Purchasing Decisions and Food Consumption: Chile
Official title: Do Taxes on Unhealthy Foods and Subsidies on Healthy Foods Work in Chile ?: Study of Purchasing Decisions and Food Consumption
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Evaluate the Effectiveness of Taxes on Unhealthy
Evaluate the Effectiveness Subsidies for Healthy Foods
Keywords: subsidies
taxes
Nutrition policy
Health policy
Lead sponsor: Universidad Mayor
Sponsor class: OTHER
Collaborators: name: Sociedad Chilena de Pediatría
First posted: 2020-12-04
Enrollment: 360
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Experimental design that simulates real purchase scenarios to evaluate the effects of a fiscal policy on purchase intention. Participants will be randomly assigned to the different intervention and control groups. Each participant must make a purchase in the virtual supermarket.

The study groups used in this research :

1. First intervention group (IG1), a "High in" food tax will be applied to study the changes in the purchasing and consumption behavior of the participants in this group. The tax will correspond to a 20% increase over the market price, that is, a tax that reaches the levels recommended by the WHO.
2. second intervention group (IG2), a subsidy will be applied to fruits and vegetables that means a reduction of 20% in their price, to study the changes in the purchasing and consumption behavior of the participants of said group.
3. control group (CG) the market or current prices of "High in" foods and subsidies of fruits and vegetables will be applied.
Primary purpose: PREVENTION

Brief summary: Objective: To evaluate the effectiveness of taxes on unhealthy foods and subsidies for healthy foods in modifying the purchasing and consumption behavior of people in the Metropolitan Region, Chile.

Research hypothesis:

1. The application of a tax that increases the price of "High in" foods by 20% will reduce the purchase and consumption of these foods by 24%.
2. The application of a subsidy that reduces the price of fruits and vegetables by 20% will increase the purchase and consumption of these foods by 17%.
3. People of lower socioeconomic status are more sensitive to price changes than people of higher socioeconomic status.

Methodological design. The research proposal proposes an experimental design that will select the participants from a panel composed of people over 18 years of age, men and women, and of all socioeconomic levels. The methodological design considers a random assignment of the people eligible for the study into 3 groups:

1. First group of intervention (GI1): people who will make their purchases with taxes on food and beverages "High in";
2. Second intervention group (GI2): people who will make their purchases with subsidies for fruits and vegetables;

4. Control group (CG) that will make the purchases with the market prices or currently applied by the supermarkets or purchase scenarios.

Methodology. Participants will make a monthly simulated purchase through a simulated supermarket system with products similar to those found in real supermarkets, including "High in" products and fruits and vegetables. Different prices will be applied to each group depending on the type of food. With the data of simulated purchases, a variation of the demand and by socioeconomic subgroup will be calculated. The results will be compared with the control group.

Expected results. GI1 participants are expected to modify their purchase intention with the "High in" food tax, decreasing the purchase of these products in their simulated purchases, compared to CG participants who will make their simulated purchases without taxes. Likewise, IG2 participants are expected to modify their purchase intention with the fruit and vegetable subsidy, increasing the purchase of these foods, compared to CG participants. Finally, it is assumed that the reduction in simulated purchases of "High in" foods and the increase in simulated purchases of fruits and vegetables vary according to socioeconomic level.


Eligibility criteria: Inclusion Criteria:

* Over 18 years of age.
* Person responsible for household purchases.
* Living in a household with one or more boys or girls between 2-14 years of age

Exclusion Criteria:

* That in the home there are no dietary restrictions that prevent the development of this research such as eating disorders, food allergies

Primary outcomes:
measure: healthiness of the total shopping
timeFrame: one measurement per participant (requested to purchase food for 15 days)
Secondary outcomes:
Other outcomes:
Locations:
city: Santiago
country: Chile
facility: Carolina Gamboa Vidal
state: Región Metropolitana
Study officials:
affiliation: Escuela de Salud Pública Universidad Mayor, Chile
name: Carolina G Vidal
role: PRINCIPAL_INVESTIGATOR
References:
citation: Waterlander WE, Steenhuis IH, de Boer MR, Schuit AJ, Seidell JC. Introducing taxes, subsidies or both: the effects of various food pricing strategies in a web-based supermarket randomized trial. Prev Med. 2012 May;54(5):323-30. doi: 10.1016/j.ypmed.2012.02.009. Epub 2012 Feb 23.
citation: Waterlander WE, Steenhuis IH, de Boer MR, Schuit AJ, Seidell JC. The effects of a 25% discount on fruits and vegetables: results of a randomized trial in a three-dimensional web-based supermarket. Int J Behav Nutr Phys Act. 2012 Feb 8;9:11. doi: 10.1186/1479-5868-9-11.