To report the design and baseline results of a rewards-based incentive to promote purchase of fruit and vegetables by lower-income households.

A four-phase randomized trial with wait-listed controls. In a pilot study, despite inadequate study coupon use, purchases of fresh fruit (but not vegetables) increased, but with little maintenance. In the present study, credits on the study store gift card replace paper coupons and a tapering phase is added. The primary outcome is the number of servings of fresh and frozen fruit and vegetables purchased per week.

A large full-service supermarket located in a predominantly minority community in Philadelphia, Pennsylvania, USA.

Fifty-eight households, with at least one child living in the home.

During the baseline period, households purchased an average of 3·7 servings of fresh vegetables and an average of less than 1 serving of frozen vegetables per week. Households purchased an average of 1·9 servings of fresh fruit per week, with little to no frozen fruit purchases. Overall, the range of fresh and frozen produce purchased during this pre-intervention period was limited.

At baseline, produce purchases were small and of limited variety. The study will contribute to understanding the impact of financial incentives on increasing the purchases of healthier foods by lower-income populations.

To examine whether parents offering a sticker reward to their child to taste a vegetable the child does not currently consume is associated with improvements in children's liking and consumption of the vegetable.

A randomized controlled trial evaluated the effectiveness of exposure only (EO) and exposure plus reward (E + R), relative to a control group, on children's liking and consumption of a target vegetable. Assessments were conducted at baseline and 2 weeks from baseline (post-intervention). Follow-up assessments were conducted at 4 weeks and 3 months from baseline.

The study took place in Adelaide, South Australia. Participants were self-selected in response to local media advertisements seeking to recruit parents finding it difficult to get their children to eat vegetables.

Participants were 185 children (110 boys, seventy-five girls) aged 4–6 years and their primary caregiver/parent (172 mothers, thirteen fathers).

The E + R group was able to achieve more days of taste exposure. Both EO and E + R increased liking at post-intervention compared with control and no further change occurred over the follow-up period. All groups increased their intake of the target vegetable at post-intervention. Target vegetable consumption continued to increase significantly over the follow-up period for E + R and control but not for EO.

The findings provide support for the effectiveness of using a sticker reward with a repeated exposure strategy. In particular, such rewards can facilitate the actual tastings necessary to change liking.