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 over up to 26 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., 1-2 weeks before the farmers' market a household shops at closes for the season). 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.