Effective interventions to increase fruit and vegetables intake in children used at least three behavior change techniques

While health benefits of fruit and vegetables are well-known for children, their intake remains insufficient among this population in the US. A growing number of interventions are designed to promote their intake at preschool age, as this stage of life may be an optimal time for dietary interventions. The impact of those interventions is assessed by numerous reviews, yet those present key gaps and inconsistencies. A recent systematic review was therefore conducted, taking into account all these gaps, to assess interventions’ effectiveness in improving fruit and vegetables intake. According to this work, multicomponent interventions, including nutrition education and behaviour change techniques (BCT) are the most effective.

With only 40% and 7% of all US children (2-18 years old) meeting the recommended intake for fruit and vegetables respectively, it is essential to develop strategies to improve their consumption in children as these foods are critical to support proper brain and body development (Wachs et al, 2014). Preschool age (2-5 years old) may be an optimal time for dietary interventions as during this stage, children begin developing their own dietary habits by gaining autonomy over their food choices (Lioret et al, 2020).

Numerous scientific reviews aimed to evaluate the impact of dietary interventions in promoting fruit and vegetables in children, yet they present key gaps and inconsistencies. A recent review (Hasan et al, 2023) was therefore conducted to systematically identify published randomized controlled trials (RCTs) evaluating childcare- or preschool-based interventions designed to increase objectively measured intake of fruit, vegetables, or both in US preschool children (aged 2-5 years). In addition, the review also aimed to identify whether each study used or not BCTs (see box) and to assess their effectiveness in improving fruit and vegetables intake.

Interventions that include nutrition education components were consistently effective at improving fruit and vegetables intake, especially if they contain multiple components

A total of nine interventions were identified according to the eligibility criteria of the review, six of them significantly increased fruit and vegetables intake. The use of nutrition education was incorporated in five of the six effective interventions.

All interventions based on nutrition education were interactive for children and improved their fruit and vegetables intake. Merely the knowledge of the importance of fruit and vegetables led to increases in consumption.

Other similar reviews to this work showed comparable findings. Particularly, interventions related to experiential learning of nutritional concepts and healthy eating improved significantly fruit and vegetables preference and intake in young children, compared to those relying on parental involvement or contingent reinforcement (Dudley et al, 2015), and especially if they contain multiple components or strategies (Charlton et al, 2021 ; Varman et al, 2021).

Manipulating the feeding environment was not consistently effective solely and need to be accompanied by an additional component

Changing the feeding environment was not consistently effective according to this work. The only manipulation that was effective at improving fruit intake, but not vegetable, was serving fruit and vegetables five minutes before the rest of the meal (Harnack et al, 2012).

Conversely, interventions that manipulated the feeding environment by providing pre-portioned meals at preschool (Harnack et al, 2012) or sent fruit and vegetables for children to take home without directly educating children, showed inconsistent results including decreases in fruit and vegetables intake. These findings suggest that an improvement of fruit and vegetables intake amongst preschoolers cannot be achieved solely by making them more available but an additional component, such as nutrition education, may be required (Nicklas et al, 2017).

Effective studies used at least three « Behavior change techniques », although no association was observed between their use and the intervention effect

According to the review, studies with no significant improvement in fruit and vegetables intake used fewer BCTs whereas effective studies used at least three BCTs and covered at least two domains of the 16. The most commonly used domains were “Antecedents” with the BCT “Adding objects to the environment” and “Identity” with the most commonly used BCT “Framing/reframing”. The most frequently used domains were “Antecedents” and “Repetition and substitution”.

However, overall, findings suggest that no association was observed between use of BCTs and intervention effect.

Key gaps are still present in this field despite the promising results

Despite the promising results reported by some of the studies identified in this review, there are still key gaps in this field. The authors stressed the need for more studies to test fruit and vegetables interventions in US childcare settings that:

1. Use robust designs with objective measures of dietary intake,
2. Directly compare intervention components and BCTs using a factorial model,
3. Include follow-up measures to assess long-term behavior change.

Based on: Hasan F, et al. Preschool- and childcare center-based interventions to increase fruit and vegetable intake in preschool children in the United States: a systematic review of effectiveness and behavior change techniques. Int J Behav Nutr Phys Act. 2023 Jun 3;20(1):66.