A competition scheme to improve the intake of healthy food by children at lunchtime increases their likelihood of choosing a fruit or vegetable and leads to enduring habits.
Poor nutrition is linked to high blood pressure, high blood glucose, and obesity. According to the World Health Organization, these three conditions are within the top five which present the highest risks for mortality. To reduce the number of people affected by these conditions due to poor nutrition, interventions are needed to provide information on healthy eating habits to change eating behaviours in the long-term. Incentives have proven to motivate people to exercise and eat better, but it is uncertain as to what incentives work best for certain groups of people. Instilling healthy eating habits in children so that they will hopefully make better food choices as adults is a strategy that has great promise. A group of researchers in England set out to examine whether the intake of fruits and vegetables by school-aged children at lunchtime could be improved by providing incentives.
The researchers conducted their field studies in 31 schools in England to examine healthy food eating behaviours of children in Grades 2 (6-7 years old) and 5 (10-11 years old) for 6 weeks.The first week was used to establish baseline levels for healthy item choices, followed by 4 weeks of treatment, and then a final week with the treatment removed. Participating schools had similar numbers of students as well as school characteristics like socioeconomic background of students, school quality, and school type. The treatment groups consisted of a control group who received no incentives, an individual-based incentive group, and a competition-based incentive group. In both incentive schemes, students were given a sticker for bringing or choosing a fruit or vegetable as part of their lunch for 4 weeks. On Friday afternoon, the children had the opportunity to choose a larger prize if they had collected 4 stickers during the week.
In the individual-based incentive scheme, each student participated in the scheme on their own. In the competition-based incentive scheme, children were randomly assigned to a group of four and at the end of the week, the child in that group the most stickers was able to choose a larger prize. Children did not know which group they were assigned to until the end of the week to prevent them from strategizing with others. In the case where there was a tie, all children with the highest number of stickers were eligible to choose a prize. It was hypothesized that children will choose and consume more fruit and vegetables if they were rewarded for bringing or choosing them at lunchtime, and that they will continue to do so after the reward was removed. Lunch monitors recorded whether children ‘tried’ or consumed the fruit or vegetable.
Overall, there was no statistically significant differences between the control group and two incentivized groups. In fact, children in the control and incentive groups were choosing a fruit or vegetable with their lunch 83% of the time at baseline. During the first week of incentives, significantly more fruits and vegetables were chosen and consumed, but the likelihood of this action increased in the control group to eventually catch up to incentive group levels. The introduction of an incentive, however, increased the probability of a child to ‘try’ a healthy item, defined in this study by eating a portion of the fruit or vegetable. At baseline levels, 70% of students tried a healthy item. With the introduction of incentives, there was a significant and immediate increase in consumption of fruit and vegetables to approximately 75% in the incentive groups. After 3 weeks, a divergence in activity was observed between the incentive groups, where the incentive effect was diminished in the individual-incentive scheme to 68%, but the effect of competition remained constant at 75% through weeks 3 and 4. These results show that the competitive incentive scheme had a positive and enduring effect over 4 weeks in increasing the consumption of fruits and vegetables.
Age, gender, and socioeconomic status of children also played a role in their choices. In the week immediately following the removal of the incentive, it was observed that younger children continued to choose less fruit and vegetables, whereas older children chose healthy items 16% more often than they did at baseline. Older children also responded more positively to individual incentives. Competition-based incentives worked better for young children, girls, and children of lower socioeconomic status, suggesting that competition-based schemes may be a more effective strategy to facilitate the consumption of fruits and vegetables in these subgroups. The overall effect of the incentive schemes was mixed as boys and older children tended to respond consistently and more positively in the last week with no incentives, whereas young children responded negatively. Schools were contacted 6 months following the study to conduct an additional week of monitoring, and the majority (21 of 31 schools) agreed the effects of the study led to more enduring habits.
This study demonstrates how two different incentive schemes impact the choice of fruit and vegetables for lunch in school-aged children. Although it was discovered that individual and competitive schemes have different effects in certain subgroups of children, the competition-based incentive scheme was more robust and effective overall. The individual scheme, in contrast, had varying effects and was relatively short-lived. According to the researchers, future studies should focus on more research to explore further differences between subgroups and which interventions work best to increase healthy food choices.
Written By: Fiona Wong, PhD