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. 2022 Aug 10;81(3):304–321. doi: 10.1093/nutrit/nuac057

Table 3.

Characteristics of included systematic reviews and meta-analyses

Delgado-Noguera et al. (2011)36 (3/19)

Reference (relevant/total primary studies) Outcomes assessed Components assessed (no. of primary studies) Standardized mean differences or ESsa and main results and findingsb Conclusionsb
FV intake

  • FV provision (1 RCT)

  • Gaming/computer (2 RCTs)

  • SMD

  • FV provision: no significant results (SMD: 0.02 (95% CI -0.11, 0.14)

  • Gaming/computer: 2 studies showed positive effect (SMD, 0.33 [95%CI, 0.16, 0.50] and SMD, 0.27 [95%CI, 0.06, 0.48]).

  • FV provision: the intervention was not effective

  • Gaming/computer: the interventions were effective in increasing FV intake
Dudley et al. (2015)1 (16/49)

  • FV intake

  • NK

  • Gaming/computer (1 CCT and 2RCTs)

  • Curriculum (4 RCTs, 6 NRCTs)

  • Experiential learning (1 NRCT)

  • Reward/incentives (1 NRCT, 1 RCT)

  • ES (Cohen’s d)

  • Gaming/computer: 1 study indicated positive effect on NK and FV intake (ES, 0.77 and E, 0.15, respectively) and 1 study found significant effect on NK (ES, NR). One study did not find any significant results.

  • Curriculum: Five studies found significant results for F/V intake, FV intake, or NK, but did not report ES. Three studies did not find significant results for NK, V intake, or FV intake. One study found positive effect on FV intake, V intake, and NK (ES, 0.10, 1.04, and NR, respectively), but no effect on F intake (NS). One study found positive effect on F intake, V intake, and NK (ES, 0.74, 0.28, 0.59, respectively), but no significant effect on FV intake (ES, 0.47).

  • Experiential learning: 1 study found positive effect on NK in 2 groups grades K–3 and grades 4–6 (ES: 1.98 and 1.94, respectively).

  • Reward/incentives: 1 study showed positive effect on F intake for both age categories (ES for ages 5–7 y; 2.12; and ES for ages 7–11 y: 2.36) and significance was NR for V intake, but the ESs were, for ages 5–7 y and 7–11 y, 2.01 and 1.51, respectively. One study showed significant results for V intake but ES was NR.

  • Gaming/computer: mixed results, but slightly positive effect on FV intake and NK

  • Curriculum: mixed results, but the curriculum component generally contributes to enhancement of FV intake and NK

  • Experiential learning: positive effect on NK, but only based on 1 study

  • Reward/incentives: positive effect on F and V intake, but only based on 2 studies that include some insufficient data (NR)
Evans et al. (2012)19 (8/27) FV intake

  • FV provision (2 RCTs, 3 NRCTs)

  • Gaming/computer (2 RCTs)

  • Curriculum (1 NRCT)

  • Weighted MD (95%CI) by using n and SEM

  • FV provision: 2 studies did not find an effect, 1 study found positive effect on FV intake (increase of 1 FV portion), 1 study indicated positive effect on F intake (MD, 0.09 [–0.20, 0.38]) and 1 study found positive effect on V intake (0.1 portion difference), but no effect on FV intake.

  • Gaming/computer: 1 study found positive effect on V intake (MD, 0.24 [0.10, 0.38]), and 1 study found slightly positive effect on V intake (MD, 0.02 [–0.14, 0.18]), but negative effect on F intake (MD, –0.10 [–0.22, 0.02]).

  • Curriculum: 1 study found positive effect on FV intake (MD, 2.7 [–0.12, 5.52]) and V intake (MD, 2.10 [0.96, 3.24]), but negative effect on F intake (difference, –0.5 portion).

  • FV provision: mixed results with neutral/positive effects, with only few positive effects found on FV intake

  • Gaming/computer: positive effect on V intake, but negative effect on F intake (which is only based on 1 study)

  • Curriculum: positive effect on FV and V intake, but negative effect on F intake (only based on 1 study)
Langellotto et al. (2012)37 (3/20)

  • FV intake

  • NK

  • Curriculum (1 NRCT)

  • Experiential learning (2 NRCTs)

  • ES (Hedge’s g)

  • Curriculum: 1 study found positive effect on F (intervention ES, –0.141, control ES, –0.256) and V intake (intervention ES, 0.038, control ES, –0.126).

  • Experiential learning: 1 study found positive effect on F (intervention ES, 0.115, control ES, –0.028) and V intake (intervention ES, 0.122, control ES, –0.082), and 1 study found negative effect on NK (intervention ES, 0.201, control ES, 0.274), but positive effect on V intake (intervention ES, 3.75, control ES, –0.106).

  • Curriculum: positive effect on F and V intake but based on 1 study

  • Experiential learning: positive effect on F and V intake, but negative effect on NK (the NK result is based on 1 study)
Metcalfe et al. (2020)38 (4/29) FV intake Nudging (4 RCTs)

  • Outcome results (based on primary studies)

  • Nudging: 2 studies did not find any significant results, 1 study found positive effect on F intake (0.73 servings pre- and 0.83 postintervention), and V intake (0.57 servings pre- and 0.86 postintervention). One study found positive effect on F consumption (students who selected fruit were more likely to consume fruit in the intervention school [87%] compared with the control schools [65%]; odds ratio, 2.3, [95%CI, 1.3–4.2]).

 Nudging: mixed results with neutral/positive effects. Two studies showed positive effect on F and/or V intake.
Micha et al. (2018)22 (6/91) FV intake FV provision (4 RCTs, 2 NRCTs)

  • ES (mean changes standardized across studies to consistent units such as 80 g serving/d for FV intake)

  • FV provision: 3 studies found positive effect on F intake (ES, 0.09, 0.30, and 0.43). One study found positive results on F intake (ES, 0.10), negative results for V intake (ES, –0.10) and neutral results for FV intake (ES, 0.00). One study found positive results for F intake and FV intake (ES, 0.58 and 0.55, respectively), and negative results for V intake (ES, –0.03). One study found positive results for FV intake (ES, 0.50).

 FV provision: positive effect on F intake, negative effect on V intake (based on 2 studies), and neutral/positive effect on FV intake
Morgan et al. (2020)39 (1/23) FV intake Caregiver involvement (1 RCT)

  • MD (95%CI) between intervention and control group

  • Caregiver involvement: 1 study showed positive effect on FV intake (MD, 0.38 servings/d [–0.51, 1.27]).

 Caregiver involvement: positive effect on FV intake, but only based on 1 study
Silveira et al. (2011)40 (5/24) FV intake

  • FV provision (3 RCTs)

  • Gaming/computer (2 RCTs)

  • Outcome results (based on primary studies)

  • FV provision: 1 study showed positive effect on F intake (MD, 0.31 pieces/d), 1 study did not find significant results, and 1 study showed positive effect on FV intake (servings/d) at school (post hoc analysis: intervention, 1; control, 0.5), but nonsignificant results for FV intake at home.

  • Gaming/computer: 1 study showed positive effect on F and V intake (MD, 0.52 and 0.24 respectively) and 1 study resulted in nonsignificant results.

  • FV provision: mixed results, neutral/positive effect on F and FV intake

  • Gaming/computer: mixed results, 1 no effect, 1 positive on F and V intake
a

ESs with r = 0.10 are defined as small effect—the effect explains 1% of the total variance; r = 0.30 as medium effect—the effect accounts for 9% of the total variance; and r = 0.50 is defined as large effect—the effect accounts for 25% of the variance.34

b

Based on only relevant primary studies (eg, primary studies on adults, or after-school programs only are not included).

Abbreviations: CCT, cluster-controlled trial; ES, effect size; F, fruit; FV, fruit and vegetables; MD, mean difference; NK, nutrition knowledge; NR, not reported; NRCT, nonrandomized controlled trial; NS, nonsignificant; QET, quasi-experimental trial; RCT, randomized controlled trial; SMD, standard mean difference; V, vegetable.