Would you pay your kids to eat their fruit and vegetables? Science says it's worth a try

Bribery could be effective in getting your children to form long-term healthy eating habits, finds study.
Bribery could be effective in getting your children to form long-term healthy eating habits, finds study. Photo: Getty Images

Would you pay your kids to eat their fruit and vegetables? Sounds ridiculous, right? And yet - new research suggests that when it comes to building long-term healthy eating habits, a little incentive (read: bribery) could actually go a long way.

A study published in the Journal of Health Economics, recruited 40 schools in Utah to participate in a program designed to promote healthy eating in their students. 

The research involved 8000 children in grades 1- 6 over an 18-month period.

Participating students were able to receive a token each day for consuming at least one serving of fruit or vegetables. Worth 25 cents each, students could used their tokens at the school store, carnival or book fair.

Schools were assigned to complete the program for either three or five weeks – the authors highlighting the conventional wisdom that it takes 21 days to form a habit. 

Students' fruit and vegetable consumption was tracked before, during and two months after the program. To ensure no "cheating", researchers were present in the cafeterias to observe students' lunch trays.

And the results were surprising. 

The researchers found that receiving tokens resulted in a dramatic increase in the amount of fruit and vegetables students consumed during the incentive period. Most importantly however, students didn't just eat more fruit and vegetables when they were getting the tokens -– the behaviour change lasted for at least two months after children stopped receiving incentives.

More specifically, two months after the tokens stopped, schools that ran the program for three weeks had 21 per cent more students eating at least one serving of fruit or vegetables at lunch time than before.

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For schools that handed out tokens for five weeks, the results were even better: two months later there was a 44 per cent increase in fruit and vegetable consumption among students.

Looking more closely at the results, the researchers found that while girls and boys increased their fruit and vegetable intake at similar levels, boys had slightly lower levels of habit formation. In addition, incentives were more effective in younger children.

The use of extrinsic rewards (such as a star chart) to reinforce certain behaviours is not without its controversy, however. As the authors highlight, prior research has shown that it can crowd out intrinsic motivation - or the internal "good" feeling you get from doing something.

And yet, the authors note, this criticism overlooks the role habit formation plays in promoting long-term behavioural change.

So how – and why – did the brief incentive program work? The researchers propose three explanations for the effect:

1."Classic" habit formation: Students grew used to eating fruits and vegetables over lunch - and the behaviour became an automatic pattern.

2. Consuming fruits and vegetables may have resulted in some students either rediscovering certain tastes or being exposed to new ones. As the authors note, "repeated exposure to specific items can influence an individual's food preferences."

3. Making fruit and vegetables more "popular" (albeit via tokens, the authors write) may have shifted social norms around consuming these foods.

"Regardless of which mechanism or combination of mechanisms is at work, however," the researchers conclude, "we did observe a sustained post-intervention increases in fruit and vegetable consumption at a modest cost."

While it's certainly positive that students were still selecting fruits and vegetable two months down the track, would they still be doing so six to 12 months later? Well, that part isn't quite so clear.

And yet, if you're at your wits' end with your picky eater - perhaps it's worth a try.

What do you think? Would you pay your kids to eat more fruit and vegetables?

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