Impact of Healthy Food Subsidies on Diet Quality and Food Security

NCT ID: NCT06992947

Last Updated: 2025-12-31

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 538 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-06-07
• Study Completion Date: 2025-12-16

Brief Summary

The British Columbia Farmers' Market Nutrition Coupon Program (FMNCP) provides lower-income households with coupons to purchase healthy foods at farmers' markets. This pragmatic randomized controlled trial (RCT) will examine the effectiveness and cost-effectiveness of two higher subsidies for healthy food ($54/weeek or $81/week), compared to the usual FMNCP healthy food subsidy ($27/week), on the diet quality (primary outcome), food insecurity, and other health-related outcomes of 276 parent-child dyads with lower incomes. 276 parent-child dyads who are enrolled in the FMNCP will be randomly assigned to one of the three subsidy arms. Participants will receive 16 weeks of coupons that can be redeemed for up to 20 weeks. Outcomes will be assessed in one parent (18-64 years) and child (6-17 years) from each household pre-, mid- and post-intervention.

Detailed Description

Background: The British Columbia Farmers' Market Nutrition Coupon Program (FMNCP) is a healthy eating initiative designed to facilitate access to nutritious food for lower-income households. The program provides households with 16 weeks of coupons valued at $27/week to purchase healthy foods at BC farmers' markets, including fruits, vegetables, dairy, meat, poultry, fish, eggs, nuts, fruit and vegetable plants, honey and herbs. The expectation is that individuals will purchase and consume healthier foods when they are financially supported to do so, and that their overall well-being and health will improve as a result.

In a prior randomized controlled trial (RCT) in adults, the investigators found that the FMNCP did not improve adults' diet quality; however, it did reduce household food insecurity by 79%. It is hypothesized that parents in the prior RCT predominantly used their subsidies to feed their children and that higher subsidies are needed to ensure both parents and children benefit. A novel dose-response RCT among parent-child dyads is essential to examine how variations in subsidy amounts affect distinct outcomes among parents and children.

This pragmatic RCT will examine the effectiveness and cost-effectiveness of two higher subsidies for healthy food, compared to the usual FMNCP healthy food subsidy, on the diet quality (primary outcome), food insecurity, and other health-related outcomes of 276 parent-child dyads with lower incomes. The primary outcome is overall diet quality post-intervention. Secondary outcomes mid- and post-intervention include: 1) Other dietary outcomes: overall diet quality (mid-intervention only), diet quality components, food purchasing, intake of ultra-processed foods; 2) Food insecurity: food insecurity status and severity, nutrition security, parental shielding; and 3) Self-reported health-related outcomes: mental well-being, sense of community, perceived stress, perceived health, food literacy, BMI.

Methods: In this single-blind, three-arm, parallel-group pragmatic RCT, 276 parent-child dyads in lower-income households will be randomized to receive the usual FMNCP healthy food subsidy ($27/week) or a subsidy that is two ($54/week) or three times ($81/week) higher. Participants will receive 16 weeks of coupons that can be redeemed for up to 20 weeks. Outcomes will be assessed in one parent (18-64 years) and one child (6-17 years) from each household pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., after participants have redeemed at least 15 weeks of coupons). Dietary intake will be collected via two 24-hour dietary recalls using the Automated Self-Administered 24-hour Dietary Recall at each time point to assess diet quality. Foods purchased with coupons will be assessed by analyzing pictures taken by participants. Food insecurity and other health-related outcomes will be assessed using validated self-reported instruments. Mixed effects regression will assess the effects of the interventions, relative to the usual food subsidy, on outcomes in parents and children. A full incremental analysis will quantify the cost-effectiveness ratios of the three healthy food subsidies.

Conditions

Food Insecurity

Keywords

Randomized controlled trial; diet quality; food insecurity; low-income; healthy food subsidy; adults; children; parental shielding; dose-response; farmers market

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: TRIPLE

Study Groups

SUBSIDY-2

Participants in this group will receive 16 weeks of coupons valued at $54/household/week, which is two times higher than the usual FMNCP subsidy. The subsidy will be provided in the form of coupons that can be used to purchase healthy foods at BC farmers' markets, including vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs. Participants will also be invited to participate in nutrition skill-building activities (e.g. cooking and gardening classes) offered by community partners. Participation in these activities is optional, which is consistent with the existing FMNCP.

Group Type: EXPERIMENTAL

Healthy food subsidy: $54/household/week

Intervention Type: OTHER

Participants receive 16 weeks of coupons valued at $54/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Nutrition skill-building

Intervention Type: OTHER

Participants are eligible, but not required, to attend optional nutrition skill-building activities (e.g. cooking and gardening classes).

SUBSIDY-3

Participants in this group will receive 16 weeks of coupons valued at $81/household/week, which is three times higher than the usual FMNCP subsidy. The subsidy will be provided in the form of coupons that can be used to purchase healthy foods at BC farmers' markets, including vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs. Participants will also be invited to participate in nutrition skill-building activities (e.g. cooking and gardening classes) offered by community partners. Participation in these activities is optional, which is consistent with the existing FMNCP.

Group Type: EXPERIMENTAL

Healthy food subsidy: $81/household/week

Intervention Type: OTHER

Participants receive 16 weeks of coupons valued at $81/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Nutrition skill-building

Intervention Type: OTHER

Participants are eligible, but not required, to attend optional nutrition skill-building activities (e.g. cooking and gardening classes).

SUBSIDY-Usual

Participants in this group will receive 16 weeks of coupons valued at $27/household/week, which is the usual FMNCP subsidy. The subsidy will be provided in the form of coupons that can be used to purchase healthy foods at BC farmers' markets, including vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs. Participants will also be invited to participate in nutrition skill-building activities (e.g. cooking and gardening classes) offered by community partners. Participation in these activities is optional, which is consistent with the existing FMNCP.

Group Type: ACTIVE_COMPARATOR

Healthy food subsidy: $27/household/week

Intervention Type: OTHER

Participants receive 16 weeks of coupons valued at $27/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Nutrition skill-building

Intervention Type: OTHER

Participants are eligible, but not required, to attend optional nutrition skill-building activities (e.g. cooking and gardening classes).

Interventions

Healthy food subsidy: $27/household/week

Participants receive 16 weeks of coupons valued at $27/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Intervention Type: OTHER

Healthy food subsidy: $54/household/week

Participants receive 16 weeks of coupons valued at $54/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Intervention Type: OTHER

Healthy food subsidy: $81/household/week

Participants receive 16 weeks of coupons valued at $81/week to purchase healthy foods at BC farmers' markets. Eligible foods include vegetables, fruits, dairy, meat, poultry, fish, eggs, nuts, vegetable and fruit plants, honey and herbs.

Intervention Type: OTHER

Nutrition skill-building

Participants are eligible, but not required, to attend optional nutrition skill-building activities (e.g. cooking and gardening classes).

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Meet existing FMNCP-specific annual household income eligibility cut-offs that account for the local cost of living
• Have 2-5 members in the household, specifically with a parent 18-64 years and a child 6-17 years. If there are multiple eligible individuals, the parent who is the primary food shopper and the youngest child will be enrolled.
• Parent-child dyads must reside together ≥5 days/week
• Are the only dyad in their household participating in the study
• Have access to the internet and a camera
• Able to communicate in English or have someone to translate

Exclusion Criteria

• Trying to conceive, pregnant or breastfeeding
• Participating in other trials that might interfere with the intervention
• Reside in a facility that provides meals (e.g., shelter, long-term care) or where they cannot prepare meals (e.g., hotel)
• Anticipate being outside of their community for >2 consecutive weeks during the study
• Expect to move to a non-FMNCP community during the study
• Expect a significant change in their household income or composition during the study

• Minimum Eligible Age: 6 Years
• Maximum Eligible Age: 64 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Canadian Institutes of Health Research (CIHR)

OTHER_GOV

Sponsor Role: collaborator

British Columbia Farmers' Market Nutrition Coupon Program

OTHER

Sponsor Role: collaborator

BC Association of Farmers' Markets

UNKNOWN

Sponsor Role: collaborator

University of Calgary

OTHER

Sponsor Role: lead

Responsible Party

Dana Lee Olstad

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Dana Lee Olstad, PhD, RD

Role: PRINCIPAL_INVESTIGATOR

University of Calgary

Locations

Participants recruited in 93 communities across British Columbia, Canada

Communities Across BC, British Columbia, Canada

Countries

Canada

Related Links

https://bcfarmersmarket.org/coupon-program/how-it-works/

BC Farmers' Market Nutrition Coupon Program

Other Identifiers

195904

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

REB24-1774

Identifier Type: -

Identifier Source: org_study_id