Adolescence is a critical time for the development of eating behaviour. Most young people are aware that healthy nutrition is important. But most of them do not eat enough vegetables and fruit, while many of them eat high-calorie products with a low nutritional value on a daily basis. Such imbalanced dietary habits have an impact on health in the short and long term. Moreover, childhood and youth are when dietary habits are developed, laying the groundwork for adult eating behaviour.
The consumption of high-calorie snacks with high fat and sugar content tends to be driven by a desire for pleasure, rather than by hunger or energy depletion. High-calorie snacks therefore have a more "rewarding" effect than low-calorie foods such as vegetables and fruit. Linking a different form of reward to healthy snacks could be a promising strategy for encouraging healthy food choices.
In the study, De Cock tested a method for encouraging young people to ultimately choose healthier snacks. This method is based on the principles of behavioural choices and rewarding desirable behaviour and involves increasing the reinforcing value of healthy snacks by associating them with a class competition.
In order to study the use of rewards in a controlled setting, 165 young people from different class groups took part in an experimental study. By performing computer assignments, they could earn points, which they could then exchange for snacks: the more points they earned, the more snacks they received. The class groups were divided into three parts:
- Group 1: could earn points to exchange for fruit: grapes, apples, pears, plums or mandarin oranges
- Group 2: could earn points to exchange for unhealthy snacks: candy bars, chocolate, marshmallows, biscuits or crisps
- Group 3: could earn points to exchange for fruit in combination with an intangible reward: the student with the highest number of points would be the class winner
Group 3 proved to have higher motivation to win fruit than Group 1, who could only earn fruit. The extra competitive aspect therefore generated an increase in the reinforcing value of the fruit. Group 3 was even practically as motivated to win the fruit as Group 2 who were working to earn unhealthy snacks.
De Cock: "If we would repeatedly reward young people for choosing healthy snacks, by means of a competition, they could ultimately associate healthy snacking in their minds with positive consequences, and make this behaviour more frequent."
However, this concept will need to be confirmed through more large-scale real-life studies. There will also need to be research to determine which rewards have the greatest effect and whether combining them with strategies that reduce the reinforcing value of unhealthy snacks would reinforce the effects.
"If further studies confirm the effectiveness of this method of rewarding, these methods could easily be applied at school or at the individual level, and could have a positive impact on the dietary habits and the current and future health of these young people", concludes De Cock.
Professor Ian Rowland, Chairman of the Scientific Advisory Committee of the Alpro Foundation, congratulates Dr. De Cock on her original and innovative study. "Dietary choices in adults are often based on habits learned at a young age. Alpro Foundation wants to spread knowledge about the health and sustainability benefits of plant-based eating and how different target groups, such as young people, can be encouraged to increase their intake of plant foods. This study provides new knowledge on the subject that can provide effective routes to achieving such dietary change. With the Alpro Foundation Award we hope to stimulate young researchers to continue with such relevant research."
17/04/2018 Alpro Foundation
Full bibliographic information
The article "Adding a reward increases the reinforcing value of fruit." De Cock N, Vervoort L, Kolsteren P, Huybregts L, Van Lippevelde W, Vangeel J, Notebaert M, Beullens K, Goossens L, Maes L, Deforche B, Braet C, Eggermont S, Van Camp J, Lachat C. This article appeared in Br J Nutr. 2017 Feb;117(4):611-620.