Poor nutrition is a primary cause behind the rising cost of health care in many developed countries. Although pupils have good knowledge of what is healthy and what is not, that does not always translate into necessarily choosing to eat fruit and vegetables. Parents and teachers know how difficult it can be to encourage children to try healthy food.
The use of incentives that reward healthy eating or other forms of good behaviour are one option being discussed as a way round this. In our recent work we explored the use of incentives in the form of stickers and small rewards – such as small toys, yoyos and stationery – in order to increase fruit and vegetable consumption among primary school children.
It worked well, but we found that adding an element of competition meant children were three times more likely to eat fruit and vegetables.
Rewards for fruit and veg
Recent research in education, smoking cessation and exercise has shown that incentives can induce individuals to engage in positive behaviour. In relation to nutrition, it remains an open question whether rewarding individuals for eating healthier will have any effect on behaviour or will play any lasting role in solving the problems caused by poor nutrition.
In order to explore this, we carried out a randomised controlled trial in 31 schools in England involving more than 600 pupils in years 2 and 5. Children’s dietary choices at lunch were monitored for a period of six weeks and an intervention was carried out in two-thirds of the schools for a period of four weeks. Sometimes we observed that children were choosing, or were given fruit and vegetables, but decided not to eat it.
Schools were randomly placed into one of three groups. In control schools, no incentives were provided for healthy eating, but pupils choices and consumption were checked. In the second group of schools, an individual-based reward scheme was carried out where children were given a sticker if they chose a fruit or vegetable for their school meal or brought one in their packed lunch. Children also received an additional small reward if they chose a healthy item on four or more days over the course of the week.
In the final group of schools, competition was introduced between the pupils. As well as being given stickers for choosing or bringing in a fruit or vegetable, if pupils collected more stickers than their peers the child with most stickers in each group would receive an additional reward, such as a highlighter pen. They were assigned randomly each week to groups of four and their group was only revealed to them at the end of the week – after all their consumption choices had been made.
We found that incentivising children to choose a fruit or vegetable at lunchtime had an overall positive effect on both choice and consumption: on average children chose 3% more fruits and vegetables and consumed 4.5% more than the control group. Of those who were initially less inclined to choose fruit and vegetables, they increased their choice of healthy items by 19% and consumed by 17% more. Those results suggest that the incentive is changing the behaviour of those students with initially poor eating habits.
But introducing an element of competition was nearly twice as effective in getting children to choose a healthy item and more than three times as effective at getting children to consume healthy items. Children in the competitive scheme chose healthy items 33% more often than those in the control group and consumed healthy items 48% more.
Girls more competitive
The effects for different age groups were stark. We found that younger children respond negatively and older children respond positively to the non-competitive incentive. These results are consistent with the findings of food neophobia (the predisposition to reject novel food) by age discussed in previous health research on how food preferences develop. Yet the competitive incentive scheme had the same effect across the board: everyone chooses and consumes more healthy items.
Girls, students from poorer backgrounds and younger children responded more positively to competition than the individual-based incentive. Boys, older children, and students from wealthier socio-economic backgrounds responded positively to both the competitive and the individual incentive scheme. But adding the element of competition had a bigger impact in nearly every case.
Using a competitive incentive could improve effectiveness by increasing the choice and consumption of those already responding to the individual scheme and those groups that typically do not respond to health interventions.
These results are important in our efforts to combat problems associated with poor nutrition. Incentives can work to encourage healthy dietary choices. But a “one-size-fits-all” reward scheme is not likely to work. The mixed effects suggest that different policies may have to be developed for different groups.
Competition-based schemes could have larger and longer-lasting effects in cases where individual-based incentive schemes do not.