Effects of financial incentives for the purchase of healthy groceries on dietary intake and weight outcomes among older adults: A randomized pilot study

Abstract

Providing financial incentives can be a useful behavioral economics strategy for increasing fruit and vegetable intake among consumers. It remains to be determined whether financial incentives can promote intake of other low energy-dense foods and if consumers who are already using promotional tools for their grocery purchases may be especially responsive to receiving incentives. This randomized controlled trial tested the effects of offering financial incentives for the purchase of healthy groceries on 3-month changes in dietary intake, weight outcomes, and the home food environment among older adults. A secondary aim was to compare frequent coupon users (FCU) and non-coupon users (NCU) on weight status, home food environment, and grocery shopping behavior. FCU (n = 28) and NCU (n = 26) were randomly assigned to either an incentive or a control group. Participants in the incentive group received $1 for every healthy food or beverage they purchased. All participants completed 3-day food records and a home food inventory and had their height, weight, and waist circumference measured at baseline and after 3 months. Participants who were responsive to the intervention and received financial incentives significantly increased their daily vegetable intake (P = 0.04). Participants in both groups showed significant improvements in their home food environment (P = 0.0003). No significant changes were observed in daily energy intake or weight-related outcomes across groups (P < 0.12). FCU and NCU did not differ significantly in any anthropometric variables or the level at which their home food environment may be considered 'obesogenic' (P > 0.73). Increased consumption of vegetables did not replace intake of more energy-dense foods. Incentivizing consumers to make healthy food choices while simultaneously reducing less healthy food choices may be important.

Keywords: Diet; Financial incentives; Groceries; Obesity.

Figure 1

Mean (± SEM) vegetable intake (cups/day) at baseline and month 3 for participants in the Control (baseline: n = 18; month 3: n = 19) and participants in the Incentive group who received financial incentives for returning nutrition facts labels for healthy foods/beverages (baseline: n = 10; month 3: n = 10). All subjects included in this subgroup analysis were deemed plausible reporters. A mixed-effects linear model with repeated measures was used to assess 3-month changes in vegetable intake by group. The results showed a significant group-by-time interaction (P = 0.04) for vegetable intake. Post-hoc comparisons indicated a significant difference in daily vegetable intake between baseline and month 3 for the Incentive group (P = 0.02; denoted by (*), but not for the Control group (P = 0.91).