Exclusion criteria

1) Descriptive only articles

2) Articles without results

3) Interventions without separate findings for attending an after-school programme

1) Obesity treatment studies

2) Unpublished articles, conference papers, dissertations

1) Articles without data results

2) Articles with only baseline data

3) Review articles

1) Descriptive articles only

2) Interventions on diets only

3) Studies involving children suffering from eating disorders or drug or alcohol problems

1) Conference abstracts

2) Unpublished articles

3) Dissertations

4) Non-English papers

Quality control

None stated

None stated

Assessed using NICE tool for randomized trials (i.e., 10 internal validity items such as study design and sample size)

None stated

None stated

Adapted version of the Quality Assessment Tool for Quantitative Studies (e.g., selection bias, blinding)

Studies

included (Number)

n = 12

n = 13

n = 9

n = 21

n = 15

n = 15

Number of studies based on a theory

Not mentioned

n = 5

n = 6

n = 8

n = 2

n = 8

Participant age (years)

8 - 12

≤18

5 - 15

Kindergarten through middle school, average age 9 to 10 years

≤19

5 - 18