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nutrients
Review
Promoting Healthy Eating among Young People—A Review of
the Evidence of the Impact of School-Based Interventions
Abina Chaudhary 1, František Sudzina 2, 3, * and Bent Egberg Mikkelsen 4
1Independent Researcher, Kastrupvej 79, 2300 Copenhagen, Denmark; abinachaudhary@yahoo.com
2Department of Materials and Production, Faculty of Engineering and Science, Aalborg University, A. C.
Meyers Vænge 15, 2450 Copenhagen, Denmark
3Department of Systems Analysis, Faculty of Informatics and Statistics, University of Economics, nám. W.
Churchilla 1938/4, 130 67 Prague, Czech Republic
4Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen,
Rolighedsvej 23, 1958 Frederiksberg C, Denmark; bemi@ign.ku.dk
*Correspondence: sudzina@business.aau.dk or frantisek.sudzina@vse.cz
Received: 1 July 2020; Accepted: 3 September 2020; Published: 22 September 2020
Abstract:
Intro: Globally, the prevalence of overweight and obesity is increasing among children and
younger adults and is associated with unhealthy dietary habits and lack of physical activity. School
food is increasingly brought forward as a policy to address the unhealthy eating patterns among
young people. Aim: This study investigated the evidence for the effectiveness of school-based food
and nutrition interventions on health outcomes by reviewing scientific evidence-based intervention
studies amongst children at the international level. Methods: This study was based on a systematic
review using the PRISMA guidelines. Three electronic databases were systematically searched,
reference lists were screened for studies evaluating school-based food and nutrition interventions that
promoted children’s dietary behaviour and health aiming changes in the body composition among
children. Articles dating from 2014 to 2019 were selected and reported effects on anthropometry,
dietary behaviour, nutritional knowledge, and attitude. Results: The review showed that school-based
interventions in general were able to affect attitudes, knowledge, behaviour and anthropometry,
but that the design of the intervention affects the size of the effect. In general, food focused interventions
taking an environmental approach seemed to be most effective. Conclusions: School-based
interventions (including multicomponent interventions) can be an effective and promising means for
promoting healthy eating, improving dietary behaviour, attitude and anthropometry among young
children. Thus, schools as a system have the potential to make lasting improvements, ensuring healthy
school environment around the globe for the betterment of children’s short- and long-term health.
Keywords: school children; food and nutrition; intervention; healthy eating
1. Introduction
Childhood is one of the critical periods for good health and development in human life [
1
,
2
].
During this age, the physiological need for nutrients increases and the consumption of a diet high in
nutritional quality is particularly important. Evidence suggests that lifestyle, behaviour patterns and
eating habits adopted during this age persist throughout adulthood and can have a significant influence
on health and wellbeing in later life [
3
,
4
]. Furthermore, the transition from childhood into adolescence
is often associated with unhealthy dietary changes. Thus, it is important to establish healthful
eating behaviours early in life and specially focus on the childhood transition period. A healthy diet
during the primary age of children reduces the risk of immediate nutrition-related health problems of
primary concern to school children, namely, obesity, dental caries and lack of physical activity [
5
–
7
].
Nutrients 2020,12, 2894; doi:10.3390/nu12092894 www.mdpi.com/journal/nutrients
Nutrients 2020,12, 2894 2 of 34
Furthermore, young people adopting these healthy habits during childhood are more likely to maintain
their health and thus be at reduced risk of chronic ailments in later life [
7
–
9
]. Thus, healthy behaviours
learnt at a young age might be instrumental in reaching the goals of good health and wellbeing of the
2030 Sustainability Agenda which has implications at the global level.
Globally, the prevalence of overweight and obesity rose by 47.1% for children and 27.5% for
adults between 1980 and 2013 [
10
]. A recent WHO (World Health Organization) Commission
report [
10
] stated that if these same trends were to continue, then by 2025, 70 million children are
predicted to be affected [
11
]. Hence, the increased prevalence might negatively affect child and adult
morbidity and mortality around the world [
12
,
13
]. Worldwide the dietary recommendations for healthy
diets recommend the consumption of at least five portions of fruits and vegetables a day, reduced
intake of saturated fat and salt and increased consumption of complex carbohydrates and fibres [
14
].
However, studies show that most children and adolescent do not meet these guidelines [
15
,
16
] and,
thus, as a result, childhood and adolescent obesity are alarming nearly everywhere [
17
]. Recent figures
show that the prevalence has tripled in many countries, making it the major public health issue in the
21st century [
18
–
21
]. According to WHO [
4
], 1 in 3 children aged 6–9 were overweight and obese in
2010, up from 1 in 4 children of the same age in 2008.
The increased prevalence of overweight and obesity has fuelled efforts to counteract the
development, as seen for instance in the action plan on childhood obesity [
17
]. Increasingly policy
makers have been turning their interest to the school setting as a well-suited arena for the promotion
of healthier environments [
18
]. As a result, schools have been the target of increased attention from
the research community to develop interventions and to examine the school environment to promote
healthful behaviours including healthy eating habits.
Globally, interventions in the school environment to promote healthier nutrition among young
people have received considerable attention from researchers over the past years. But there is far from a
consensus on what are the most effective ways to make the most out of schools’ potential to contribute
to better health through food-based actions. Is it the environment that makes a difference? Is it the
education or is it the overall attention given to food and eating that plays the biggest role? School food
and nutrition intervention strategies have witnessed a gradual change from knowledge orientation to
behavioural orientation [
22
] and from a focus on the individual to the food environment. Research
evidence has shown that adequate nutrition knowledge and positive attitudes towards nutrition do not
necessarily translate to good dietary practices. Similarly, research has shown that the food environment
plays a far bigger role in behaviour than originally believed [23,24].
School-based interventions can a priori be considered as an effective method for promoting
better eating at the population level. Schools reach a large number of participants across diverse
ethnic groups. It not only reaches children, but school staffs, family members as well as community
members [
8
,
25
]. Schools can be considered a protected place where certain rules apply and where
policies of public priority can be deployed relatively easily. In addition, schools are professional spaces
in which learning and formation is at the heart of activities and guided by a skilled and professional
staff. Schools, as such, represent a powerful social environment that hold the potential to promote and
provide healthy nutrition and education. Besides the potential to create health and healthy behaviours,
good nutrition at school has, according to more studies, the potential to add to educational outcomes
and academic performance [26–28].
However, taking the growth in research studies and papers in the field into account, it is difficult for
both the research community and for policy makers to stay up to date on how successful school-based
interventions have been in improving dietary behaviours, nutritional knowledge and anthropometry
among children. Also, the knowledge and insights into how it is possible to intervene in the different
corners of the school food environment has developed which obviously has influenced over recent
decades how programs and interventions can be designed. It has also become clear that food at school
is more than just the food taken but includes curricular and school policy components. The findings
from school-based studies on the relationship between school, family as well as community-based
Nutrients 2020,12, 2894 3 of 34
interventions and health impact suggest that health impacts are dependent on the context in which
they have been carried out as well as the methodology. Thus, an updated overview as well as a more
detailed analysis of initiatives is needed in order to develop our understanding of the nature of the
mechanisms through which the school can contribute to the shaping of healthier dietary behaviour
among children and adolescents before more precise policy instruments can be developed. Our study
attempted to fill the need for better insight into which of the many intervention components works
best. It attempted to look at school food and nutrition interventions reported in the literature that have
been looking at healthy eating programmes, projects, interventions or initiatives.
School-based interventions in the Western world are traditionally targeted at addressing obesity
and over-nutrition, but school food interventions are also addressing under nutrition and, as such,
their role in a double burden of disease perspective should not be underestimated. Many studies
have reported on micronutrient malnutrition among school-aged children in developing countries
(for instance [
29
–
31
]) but it has also been reported in the context of developed countries [
32
]. Against this
backdrop, the aim of this study was to provide an analysis of the evidence of the effectiveness of
school-based food interventions by reviewing recent scientific, evidence-based intervention studies
on healthy eating promotion at school. The specific objectives of the study were to identify which
interventions had an effect on primary outcomes, such as BMI, or on secondary outcomes such as
dietary behaviour, nutritional knowledge and attitude.
2. Materials and Methods
The functional unit of the review were healthy eating programmes, projects or initiatives that have
been performed using the school as a setting. We included only programmes, projects or initiatives that
were studied in a research context, in the sense that they were planned by researchers, carried out under
controlled settings using a research protocol, and reported in the literature. School-based programmes,
projects, interventions or initiatives are, per definition, cluster samples where a number of schools
first were chosen for intervention followed by performing an outcome measurement before and after
the intervention and, in most cases, also in one or more control schools. The outcome measurement
in the studies reviewed was performed on a sample of students that was drawn from each school
(cluster).For this, the systematic review and meta-analysis (PRISMA) guidelines and the standardised
quality assessment tool “effective public health practice project (EPHPP) quality assessment tool for
quantitative studies” were used for analysing the quality assessment of the included studies [
33
].
This EPHPP instrument can be used to assess the quality of quantitative studies with a variety of
study designs.
2.1. Literature Search
The literature review involved searches in PubMed, Web of Science and Cochrane Library database.
The search strategy was designed to be inclusive and focused on three key elements: population
(e.g., children); intervention (e.g., school-based); outcome (e.g., diet and nutrition, knowledge, attitude
and anthropometrics). The search terms used in PubMed database were: “effectiveness of school food
AND nutrition AND primary school children”, “effectiveness of school food AND nutrition AND
interventions OR programs AND among primary school children AND increase healthy consumption”,
“primary school children and education and food interventions”, “Effectiveness of school-based food
interventions among primary school”, “effectiveness of school-based nutrition and food interventions”,
“primary school interventions and its effectiveness”, and “obesity prevention intervention among
Primary schools”. Search terms such as: “effectiveness of school-based food interventions among
primary school”, “effectiveness of school based food and nutrition interventions”, “primary school
interventions and its effectiveness” and “obesity prevention interventions”, were used in the Web
of Science database. Lastly, search terms such as: “nutrition interventions in primary schools” and
“Nutrition education interventions in school” were used in the Cochrane Library database to find the
articles. In addition, reference lists of all retrieved articles and review articles [
34
] were screened for
Nutrients 2020,12, 2894 4 of 34
potentially eligible articles. The search strategy was initially developed in PubMed and adapted for use
in other databases. In addition, snowballing of the reference list of the selected articles was conducted.
2.2. Inclusion Criteria
Studies selected for the inclusion were studies which investigated the effectiveness of a school-based
interventions targeting food and nutrition behaviour, healthy eating and nutrition education as a
primary focus during the intervention. Also, to be included in this review, only articles from
2014 to 2019 were selected and of those inclusion criteria included articles targeting primary
school children aged between 5 and 14 years. Participants included both boys and girls without
considering their socio-economic background. Study design included randomized controlled trial
“RCT”, cluster randomized controlled trial “RCCT”, controlled trial “CT”, pre-test/post-test with and
without control “PP”, experimental design “Quasi”. Studies which did not meet the intervention
components/exposures, such as information and teaching (mostly for the target group and parents were
additional), family focus on social support and food focus (which mainly focuses on the availability
of free foods including food availability from school gardening), were excluded. Systematic review
papers and studies written in different language except for English were excluded as well. Studies
which met the intervention criteria but had after school programs were excluded.
2.3. Age Range
Since the review covers a broad range of different countries and since school systems are quite
different, the sampling principle had to include some simplification and standardisation. The goal
of the review was to cover elementary (primary) and secondary education and, as a result, the age
range of 5–14 was chosen to be the best fit, although it should be noted that secondary education in
some countries also covers those 15–18 years of age. In most countries, elementary education/primary
education is the first—and normally obligatory—phase of formal education. It begins at approximately
age 5 to 7 and ends at about age 11 to 13 and in some countries 14. In the United Kingdom and some
other countries, the term primary is used instead of elementary. In the United States the term primary
refers to only the first three years of elementary education, i.e., grades 1 to 3. Elementary education is,
in most countries, preceded by some kind of kindergarten/preschool for children aged 3 to 5 or 6 and
normally followed by secondary education.
2.4. Assessment of Study Eligibility
For the selection of the relevant studies, all the titles and abstracts generated from the searches
were examined. The articles were rejected on initial screening if the title and abstract did not meet
the inclusion criteria or met the exclusion criteria. If abstracts did not provide enough exclusion
information or were not available, then the full text was obtained for evaluation. The evaluation
of full text was done to refine the results using the aforementioned inclusion and exclusion criteria.
Thus, those studies that met predefined inclusion criteria were selected for this study.
2.5. Analytical Approach
The first step of data collection was aimed at organizing all studies with their key information.
In the second step, we created coded columns. A coded column served as a basis for being able to do
further statistical analysis. In other words, in a coded column we added a new construct not originally
found in the papers as a kind of dummy variable that standardized otherwise non-standardized
information, allowing us to treat otherwise un-calculable data statistically. For the impact columns,
we used the following approach to construct codes where impacts where put on a 1–4-point Likert
scale with 1 being “ineffective”, 2 “partially effective”, 3 “effective” and 4 “very effective”.
For the design column, the following approach was adopted as illustrated in the Table 1. Quasi
experimental/pre–post studies were labelled QED and were considered to always include a baseline
and follow-up outcome measurement. As the simplest design with no comparison but just a pre/post
Nutrients 2020,12, 2894 5 of 34
study of the same group, we constructed a power column and assigned 1 to this for a QED design.
For the controlled trial (CT), we assigned the power 2. A controlled trial is the same as QED but with a
comparison/control in which no interventions are made and with no randomization. We considered a
study to be of that kind if some kind of controls were made which could be, for instance, matching.
All CTs in our study included 2 types of comparisons: pre and post (baseline and follow-up) as well
as a comparison between intervention/no intervention. For the RCT/RCCT—a trial that is controlled
through the randomization—we assigned the power 3. This “top of hierarchy” design includes the
case (intervention) and a control (no intervention) and normally two types of comparisons (pre and
post) as well as an intervention/no intervention. For the context of this study, we did not differentiate
between RCTs and RCCTs. The latter is sometimes used to stress the fact that the school (or the class) is
the sampling unit from which the subjects are recruited. But since in the context of schools RCCT is
simply a variation of RCT, we coded them in the same class of power. We simply assumed that when
authors spoke about an RCT, they in fact meant an RCCT since they could not have been sampling
subjects without using the school as the unit.
Table 1.
Coding table for study designs. The table shows the types of studies examined in the review
and the power assigned to them.
Code Design Power
PP Pre-Test/Post-Test 1
OBS Observational 1
CT Controlled Trial 2
RCT Randomized Controlled Trial 3
RCCT Randomized Controlled Cluster Trial 3
Codes and categorization were used to standardize the information found in the papers for our
statistical analysis. Categorisation of the age/class level, such as EA—Early age, EML—Early middle
late, EL—Early late, was used.
For the intervention components (“what was done”) we translated all studies into three columns:
information and teaching, family and social support and environmental components, food provision
and availability. The latter was further expanded into three columns labelled as: focus on and
provisioning of F & V; free food availability through school gardening and availability of food and
healthier food environment. Our inclusion criteria were that studies should contain at least one of
these components. For the environmental component—food provision and availability intervention
components—we identified 2 distinct types: either a broad healthier eating focus or a narrow and
more targeted fruit and vegetable focus. After the coding, we started to ask questions about the data.
Most importantly, we were interested in knowing whether there existed a relationship between “what
was done” and “what was the impact”. In other words, we were interested in knowing more whether
there was a pattern in the way the studies intervened and the outcomes.
2.6. Queries Made
We performed queries for each intervention component (the independent variable in columns K,
L and M) for each single outcome measure.
Is there a relationship between age and outcome? We used the coded column (EA, EML, etc.) to
study that relationship.
In addition, we made queries regarding the relationship among study designs. For instance,
would the duration of studies influence whether an effect could be found or not? Would more powerful
designs result in more impact?
Furthermore, we made queries on the relationship between one intervention and a
multi-interventional component and their effect on the outcome measure. Also, the queries on
target groups were made. Codes such as S and NS (refer Table 4) in the column were used to study the
Nutrients 2020,12, 2894 6 of 34
relationship. In our analysis a distinction was made between “standard” and “extreme” (special cases).
From the reviewed papers, it was clear that some studies put little emphasis on the school selected.
We classified those as standard (S). However, a few papers used a stratification approach and case/cluster
selection that can be classified as an “extreme” or non-standard case. We coded these as non-standard
(NS). For instance, studies could be targeted to include only refugees or subjects of low socio-economic
status. It can be speculated that being a “special case” or extreme case could have an influence.
As a result, we reserved a code for these cases, although it became clear that they represented only
a minority.
In our study, availability plays a central role, since it is used in many food-at-school intervention
studies. Availability signals that food is “pushed” as opposed to being used in the “pull” mode,
where individuals are expected to request food in the sense that is the behaviour of the individual
that becomes the driving force rather than the “out thereness”. Availability is in most studies used
in combination with the idea of a food environment. The literature shows that availability can be of
two types. One is when food is made available for the individual to take where visibility, salience,
product placement, etc., are used as factors. The other type of availability is when it is made free
and the individual as a result does not have to pay. Free availability has been studied extensively in
intervention studies but for obvious reason it is difficult to implement “post-study” since there needs
to be a permanent financing present. The only exceptions to this are the collective meal models found
in countries such as Sweden, Finland, Estonia and Brazil as well as in the EU scheme where the EU
subsidizes the fruit.
Study design and other characteristics are provided in Table 2, and their findings are provided in
Table 3.
Nutrients 2020,12, 2894 7 of 34
Table 2.
The review sample: study design/characteristics. The table shows the 43 studies of the review Illustrating study design and study characteristics of the
included studies.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Harake et al.
[35]
2018
Impact of pilot school-based
nutrition intervention on
dietary knowledge,
attitudes, behaviours and
nutritional status of Syrian
refugee children in the
Bekaa, Lebanon
This study aimed to
evaluate the impact of a
six-month pilot
school-based nutrition
intervention on changes in
dietary knowledge, attitude,
and behavior of Syrian
refugee children enrolled in
informal primary schools
located in the rural region
of the Bekaa in Lebanon. A
secondary objective of the
study was to explore the
effect of the intervention on
the dietary intake and
nutritional status of
children.
Nutritional
knowledge,
attitude, HE &
FV
GHATA Bekaa Lebanon Quasi
experimental QED 1 x x
Adab P,et al.
[36]
2018
Effectiveness of a childhood
obesity prevention
programme delivered
through schools, targeting
>6 (more than 6 years) and
7 years old cluster
randomised controlled trial
(WAVES study)
To assess the effectiveness
of a school and family
based healthy lifestyle
programme (WAVES
intervention) compare with
usual practice, in
preventing childhood
obesity.
Anthropometry,
HE & FV WAVES
UK primary
schools from the
West Midlands
within 35 miles of
the study centre
Randomized
Controlled Cluster
Trials RCCT 3 x
Harley A, et al.
[37]
2018
Youth Chef Academy: Pilot
Results From a Plant-Based
Culinary and Nutrition
Literacy Program for Sixth
and Seventh Graders
The study aim was to
examine the effectiveness of
Youth Chef Academy
(YCA), a classroom-based
experiential culinary and
nutrition literacy
intervention for sixth and
seventh graders (11- to
13-year-old) designed to
impact healthy eating.
HE & FV,
Nutritional
knowledge YCA US (exact location
is missing) Controlled Trial
(CT) CT 2 x
Hermans R.C.J.
et al. [38]
2018
Feed the Alien! The Effects
of a Nutrition Instruction
Game on Children’s
Nutritional Knowledge and
Food Intake
The aim of this study was to
test the short-term
effectiveness of the Alien
Health Game, a videogame
designed to teach
elementary school children
about nutrition and healthy
food choices.
HE & FV,
Nutritional
knowledge AHG
Dutch, Netherland
Pre-test post-test,
experimental
study design QED 1 x
Nutrients 2020,12, 2894 8 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Piana N., et al.
[39]
2017
An innovative school-based
intervention to promote
healthy lifestyles
To describe an innovative
school-based intervention
to promote healthy
lifestyles. To evaluate its
effects on children’s food
habits and to highlight the
key components which
contribute most to the
beneficial effects obtained
from children’s, teachers’
and parents’ perspectives.
HE & FV,
Nutritional
knowledge,
Physical
activity
Kidmed
test Spoleto, Umbria Pre-test post-test PP 1 x x
Battjes-Fries
M.C.E., et al.
[40]
2017
Effectiveness of Taste
Lessons with and without
additional experiential
learning activities on
children’s willingness to
taste vegetables
The aim of this study was to
assess the effect of Taste
Lessons with and without
extra experiential learning
activities on children’s
willingness to taste
unfamiliar vegetables, food
neophobia, and vegetable
consumption.
HE & FV,
attitude TLVM Dutch province of
Gelderland
Quasi
experimental
design QED 1 x
Bogart L.M., et
al. [41]
2014
A Randomized Controlled
Trial of Students for
Nutrition and eXercise
(SNaX): A
Community-Based
Participatory Research
Study
To conduct a randomized
controlled trial of Students
for Nutrition and eXercise
(SNaX), a 5-week
middle-school-based
obesity-prevention
intervention combining
school-wide environmental
changes, multimedia,
encouragement to eat
healthy school cafeteria
foods, and peer-led
education.
HE & FV,
Nutritional
knowledge SNaX Los Angeles
Unified School
District
Randomized
Controlled Trial RCT 3 x
Shriqui V.K.,et
al. [42]
2016
Effects of a School-Based
Intervention on Nutritional
Knowledge and Habits of
Low-Socioeconomic School
Children in Israel: A
Cluster Randomized
Controlled Trial
Examining the effect of a
school-based
comprehensive intervention
on nutrition knowledge,
eating habits, and
behaviours among low
socioeconomic status (LSES)
school-aged children was
performed
Anthropometry,
HE & FV,
Nutritional
knowledge
NRI & PA Beer Sheva, a big
metropolis in
southern Israel
Randomized
Controlled Cluster
Trial RCCT 3 x x
Nutrients 2020,12, 2894 9 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Sharma S.V.et
al. [43]
2016
Evaluating a school-based
fruit and vegetable co-op in
low-income children: A
quasi-experimental study
The purpose of this study
was to evaluate the
effectiveness of a new
school-based food co-op
program, Brighter Bites
(BB), to increase fruit and
vegetable intake, and home
nutrition environment
among low-income 1st
graders and their parents.
HE & FV,
Nutritional
knowledge BB Houston, Texas
Quasi-experimental
non-randomized
controlled study QED 1 x x x
Lawlor A.D. et
al. [44]
2016
The Active for Life Year 5
(AFLY5) school-based
cluster randomised
controlled trial: effect on
potential mediators
To determine the effect of
the intervention on
potential mediators
Anthropometry,
HE & FV AFLY5 South East of
England Cluster RCT RCCT 3 x x
Steyn P.N.et al.
[45]
2016
Did Health kick, a
randomised controlled trial
primary school nutrition
intervention improve
dietary quality of children
in low-income settings in
South Africa?
To promote healthy eating
habits and regular physical
activity in learners, parents
and educators by means of
an action planning process
HE & FV,PA HK Western Cape
(WC) Province Cluster RCT RCCT 3 x
Jones M. et al.
[46]
2017
Association between Food
for Life, a Whole Setting
Healthy and Sustinable
Food Programme, and
Primary School Children’s
Consumption of Fruit and
Vegetables: A cross
Sectional Study in England
The aim of the study was to
examine the association
between primary school
engagement in the Food for
Life programme and the
consumption of fruit and
vegetables by children aged
8–10 years.
HE & FV,
Nutritional
knowledge FLP England
Cross sectional
school matched
comparison
approach
Cross-sectional
study design 1 x x
Larsen L.A. et
al. [47]
2015
RE-AIM analysis of a
randomized school-based
nutrition intervention
among fourth-grade
classrooms in California
To promote healthy eating
behaviours and attitudes in
children
HE & FV,
Nutritional
knowledge,
Attitude
NPP California
RCT with pre-,
post-, and
follow-up
assessments
RCT 3 x x
Nutrients 2020,12, 2894 10 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Shen, Hu and
Sun [48]
2015
Assessment of School-Based
Quasi-Experimental
Nutrition and Food Safety
Health Education for
Primary School Students in
Two Poverty-Stricken
Counties of West China
Aimed to assess the
reliability of the knowledge,
attitude and behaviour of
nutrition and food safety
questionnaire for primary
school students (Grade 4 to
6) in poverty-stricken
counties of China, and
evaluate the effectiveness of
health education through a
quasi experiment, in order
to promote policy
establishment for child and
adolescent health in the
future
HE & FV,
Nutritional
knowledge,
Attitude
NFSE West China
(Shaanxi and
Yunnan provinces)
Quasi-experimental
design QED 1 x
Gallotta C.M.
et al. [21]
2016
Effects of combined
physical education and
nutritional programs on
schoolchildren’s healthy
habits
To evaluate the efficacy of
three 5-month combined
physical education (PE) and
nutritional interventions on
body composition, physical
activity (PA) level,
sedentary time and eating
habits of schoolchildren
Anthropometry,
HE & FV,
Nutritional
knowledge,
PA
ESFS Rome (Italy) Randomised
Controlled Cluster
Trial RCCT 3 x x
Fairclough J.S.
et al. [49]
2013
Promoting healthy weight
in primary school children
through physical activity
and nutrition education: a
pragmatic evaluation of the
CHANGE! randomised
intervention study
To assess the effectiveness
of the CHANGE!
intervention on measures of
body size, PA and food
intake
Anthropometry,
HE & FV,PA CHANGE Wigan Borough in
northwest
England, UK
Cluster
randomised
intervention RCCT 3 x
Cunha B.D. et
al. [50]
2013
Effectiveness of a
randomized school-based
intervention involving
families and teachers to
prevent excessive weight
gain among Adolescents in
Brazil
To evaluate the
effectiveness of a
school-based intervention
involving the families and
teachers that aimed to
promote healthy eating
habits in adolescents; the
ultimate aim of the
intervention was to reduce
the increase in body mass
index (BMI) of the students
Anthropometry,
HE & FV,PA PAPPAS Duque de Caxias,
Rio de Janeiro,
Brazil
Paired cluster
randomized
school-based trial RCCT 3 x
Nutrients 2020,12, 2894 11 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Aviles O.A. et
al. [51]
2017
A school-based intervention
improved dietary intake
outcomes and reduced
waist circumference in
adolescents: a cluster
randomized controlled trial
The program aimed at
improving the nutritional
value of dietary intake,
physical activity (primary
outcomes), body mass
index, waist circumference
and blood pressure
(secondary outcomes)
Anthropometry,
HE & FV,PA
ACTIVITAL
Urban area of
Cuenca, Ecuador
Pair-matched
cluster
randomized
controlled trial
RCCT 3 x x
Muros J.J. et al.
[52]
2013
Results of a seven-week
school-based physical
activity and nutrition pilot
program on health-related
parameters in primary
school children in Southern
Spain
To determine the effect of
nutrition education
combined with sessions of
vigorous extracurricular
physical activity (VEPA) on
the improvement of
health-related parameters
in children in primary
education
Anthropometry,
HE & FV,PA VEPA Southern Spain Pilot study, PP QED 1 x
Moss A et al.
[53]
2013
Farm to School and
Nutrition Education:
Positively Affecting
Elementary School-Aged
Children’s Nutrition
Knowledge and
Consumption Behavior
To introduce the CATCH
nutrition curriculum and
Farm to School program to
assess nutrition knowledge
of 3rd grade students, and
increase their fruit and
vegetable consumption
behavior
HE & FV,
Nutritional
knowledge CATCH Southern Illinois
Quasi-experimental
design QED 1 x
Zota D. et al.
[54]
2016
Promotion of healthy
nutrition among students
participating in a school
food aid program: a
randomized trial
To evaluate the potential
benefits on students’ eating
habits, of incorporating
healthy nutrition education
as part of a school food aid
program
Anthropometry,
HE & FV DIATROFI Greece
Randomised
Controlled Trial
with the aspects of
pre and post
intervention
questionnarie
RCT 3 x x x
Gold A. et al.
[55]
2017
Classroom Nutrition
Education Combined With
Fruit and VegetableTaste
Testing Improves
Children’s Dietary Intake
To test the classroom
curriculum, go wild with
fruits & veggies! (GWWFV)
effectiveness to increase FV
intake of third graders in
rural and urban
communities in North
Dakota
HE & VF GWWFV North Dakota
Intervention study
with RCT aspects
(the schools were
randomized to
control and
intervention
school)
RCT, Intervention
study 3 x
Mbhatsani
H.V.,et al. [56]
2017
Development and
Implementation of
Nutrition Education on
Dietary Diversification for
Primary School Children
To ensure that people
consume a variety of foods
that, together, provide
adequate quantities of all
the essential micronutrients
necessary for health
HE & FV,
Nutritional
knowledge
NET &
HBoIF
Vhembe District of
Limpopo Province
in South Africa
Quasi-experimental,
with a one-group
pre-test/post-test
intervention
QED 1 x
Nutrients 2020,12, 2894 12 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Hutchinson J.
et al. [57]
2015
Evaluation of the impact of
school gardening
interventions on children’s
knowledge of and attitudes
towards fruit and
vegetables. A cluster
randomised controlled trial
To evaluate whether
ongoing gardening advice
and gardening involvement
from the Royal
Horticultural Society (RHS)
gardening specialists was
associated with better fruit
and vegetable outcomes in
children than those at
teacherled schools that
obtained standard advice
from the RHS Campaign for
School Gardening
Nutritional
knowledge,
Attitude CFSG
London boroughs,
Wandsworth,
Tower Hamlets,
Greenwich and
Sutton
Randomised
Controlled Cluster
Trial RCCT 3 x x
Viggiano A et
al. [58]
2018
Healthy lifestyle promotion
in primary schools through
the board game Kaledo: a
pilot cluster randomized
trial
The board game Kaledo
seems to improve
knowledge in nutrition and
helps to promote a healthy
lifestyle in children
attending middle and high
schools. So, this study was
conducted to investigate
whether similar effects of
Kaledo could be found in
younger children in
primary school.
Anthropometry,
HE & FV,
Nutritional
knowledge
Kaledo Campania, Italy Pilot cluster
randomized trial RCCT 3 x
Waters E. et al.
[59]
2017
Cluster randomised trial of
a school-community child
health promotion and
obesity prevention
intervention: findings from
the evaluation of fun ‘n
healthy in Moreland!
Fun ‘n healthy in Moreland!
aimed to improve child
adiposity,school policies
and environments, parent
engagement, health
behaviours and child
wellbeing
Anthropometry,
HE & FV FHM Victoria, Australia Randomised
Controlled Cluster
Trial RCCT 3 x
Xu F et al. [60]
2015
Effectiveness of a
Randomized Controlled
Lifestyle Intervention to
Prevent Obesity among
Chinese Primary School
Students: CLICK-Obesity
Study
To evaluate whether the
lifestyle intervention was
able to reduce obesity risk
and increase healthy
behaviors and knowledge
Anthropometry,
Nutritional
knowledge
CLICK-Obesity
Mainland China Randomised
Controlled Cluster
Trial RCCT 3 x x
Jung et al. [61]
2018
Influence of school-based
nutrition education
program on healthy eating
literacy and healthy food
choice among primary
school children
To examine the
effectiveness of a
school-based healthy eating
intervention program, the
Healthy Highway Program,
for improving healthy
eating knowledge and
healthy food choice
behavior among elementary
school students
Nutritional
knowledge,
HE & FV
Healthy
highway
program
Oswego County,
New York State Pre-/post-test QED 1 x
Nutrients 2020,12, 2894 13 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Jhou W et al.
[62]
2014
Effectiveness of a
school-based nutrition and
food safety education
program among primary
and junior high school
students in Chongqing,
China
Toexamine the effectiveness
of a school-based nutrition
and food safety education
program among primary
and junior high school
students in China
Nutritional
knowledge,
attitude
school-based
nutrition
and food
safety
education
Chongqing, China Pre-/post-test QED 1 x
Anderson EL,
et al. [63]
2016
Long-term effects of the
Active for Life Year 5
(AFLY5) school-based
cluster-randomised
controlled trial
To investigate the long-term
effectiveness of a
school-based intervention
to improve physical activity
and diet in children.
HE & FV,PA AFLY5 Southwest of
England
Randomised
Controlled Cluster
Trial RCCT 3 x
Griffin T.L. et
al. [64]
2015
A Brief Educational
Intervention Increases
Knowledge of the Sugar
Content of Foods and
Drinks but Does Not
Decrease Intakes in Scottish
Children Aged 10–12 Years
To assess the effectiveness
of an educational
intervention to improve
children’s knowledge of the
sugar content of food and
beverages
Nutritional
knowledge,
attitude NEMS Aberdeen,
Scotland
Randomised
Controlled Cluster
Trial RCCT 3 x
Kipping R.R.
et al. [65]
2014
Effect of intervention aimed
at increasing physical
activity,reducing sedentary
behaviour, and increasing
fruit and vegetable
consumption in children:
Active for Life Year 5
(AFLY5) school-based
cluster randomised
controlled trial
To investigate the
effectiveness of a
school-based intervention
to increase physical activity,
reduce sedentary behaviour,
and increase fruit and
vegetable consumption in
children
HE & FV,PA AFLY5 South west of
England
Randomised
Controlled Cluster
Trial RCCT 3 x
Gaar V.M.et al.
[66]
2014
Effects of an intervention
aimed at reducing the
intake of sugar-sweetened
beverages in primary school
children: a controlled trial
Aimed at reducing
children’s SSB consumption
by promoting the intake of
water
Nutritional
knowledge,
attitude
Water
campaign Rotterdam,
Netherland Controlled trial CT 2 x
Moore GF et al.
[67]
2014
Impacts of the Primary
School Free Breakfast
Initiative on socio-economic
inequalities in breakfast
consumption among
9–11-year-old
schoolchildren in Wales
To examine the impacts of
the Primary School Free
Breakfast Initiative in Wales
on inequalities in children’s
dietary behaviours and
cognitive functioning
HE & FV FSM Wales, UK Randomised
Controlled Cluster
Trial RCCT 3 x
Nutrients 2020,12, 2894 14 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Nyberg G. et
al. [68]
2016
Effectiveness of a universal
parental support
programme to promote
health behaviours and
prevent overweight and
obesity in 6-year-old
children in disadvantaged
areas, the Healthy School
Start Study II, a
cluster-randomised
controlled trial
To develop and evaluate the
effectiveness of a parental
support programme to
promote healthy dietary
and physical activity habits
and to prevent overweight
and obesity in six-year-old
children in disadvantaged
areas
Anthropometry,
HE & FV
A Healthy
School
Start
Stockholm,
Sweden
Randomised
Controlled Cluster
Trial RCCT 3 x
Mittmann S.,
Austel A., and
Ellrott T. [69]
2016
Behavioural effects of a
short school-based fruit and
vegetable promotion
programme: 5-a-Day for
kids
To evaluate the acceptance
of the scheme as well as the
short- and
intermediate-term effects of
the German “5-a-day for
kids” project
HE & FV 5-a-day for
kids Hannover,
Germany Pre-/post-test PP 1 x x
Huys N. et al.
[70]
2019
Effect and process
evaluation of a real-world
school garden program on
vegetable consumption and
its determinants in primary
schoolchildren
To investigate the
effectiveness of a school
garden program on
children’s vegetable
consumption and
determinants and to gain
insight into the process of
the program
HE & FV,
Nutritional
knowledge
Taste
Garden Ghent, Belgium
Non-equivalent
pre-test. Post–test
control group
design
PP 1 x x
Weber K.S. et
al. [71]
2017
Positive effects of
promoting physical activity
and balanced diet in a
primary school setting with
a high proportion of
migrant school children
To evaluate the effects of a
school-based intervention
offering additional hours of
supervised physical activity
and dietary education for
3rd and 4th graders in
primary schools
HE & FV,
Nutritional
knowledge
‘Be smart.
Join in. Be
fit.’
Düsseldorf,
Germany Controlled trial CT 2 x
Llargue’s E. et
al. [72]
2016
Four-year outcomes of an
educational intervention in
healthy habits in
schoolchildren: the Avall 3
Trial
To investigate the impact of
the intervention on physical
activity,BMI and
prevalence of overweight
and obesity after 4 years
Anthropometry
The Avall
project Granollers, Spain Randomised
Controlled Cluster
Trial RCCT 3 x
Martins M.L.
et al. [73]
2015
Strategies to reduce plate
waste in primary
schools—experimental
evaluation
To determine and compare
the effect of two
interventions in reducing
the plate waste of school
lunches
Nutritional
Knowledge Reduce
plate waste
City of Porto,
Portugal Controlled trial CT 2 x x
Nutrients 2020,12, 2894 15 of 34
Table 2. Cont.
Author Year Title/Reference Main Aim (from Abstract) Main Aim in
Brief
Program
Name
Location &
Country Study Design Study Design
Coded Power Intervention Components
Acronym Column I RCT, PP, CT, RCCT,
Quasi
Information
and
Teaching
Food Focus
Family/Social
Support
Environmental/Food
Focus on Healthy
Meal Availability
Environmental/Food
Focus through
School Gardening
Rosario R. et al.
[74]
2016
Impact of a school-based
intervention to promote
fruit intake: a cluster
randomized controlled trial
To examine the effects of a
six-month dietary
education intervention
programme, delivered and
taught by trained teachers,
on the consumption of fruit
as a dessert in children aged
6–12 years
HE & FV
Dietary
education
intervention
programme
City in north of
Portugal
Randomised
Controlled Cluser
Trial RCCT 3 x
Zafiropulos V.
et al. [75]
2015
Preliminary results of a
dietary intervention among
primary school children
To evaluate the
effectiveness of the dietary
intervention by measuring
body composition and
dietary behavior of children
prior to and after the
intervention
Anthropometry,
HE & FV WBDI central/eastern
Crete Greece
RCT with the
aspects of pre and
post intervention RCT 3 x
Table 3. The review sample-findings. The table shows the findings from the 43 studies of the review.
Author Year Age Age Coded Sample Size, n Time
Duration/Month Outcome Measures Effectiveness Among Children Target Group Target Group
Coded
Years EA EML EL Anthropometry HE/FV Nutritional
Knowledge Attitude Anthropometry HE/FV Nutritional
Knowledge Attitude S NS
Harake et al.
[35]
2018
6–14 years x x x 183 6 x x x x 3 3 4 2
Syrian refugee
children in grade 4 to 6
from three informal
primary schools (2
intervention and one
control)
x
Adab P,et al.
[36]
2018
6–7 years x 1392 12 x x 1 1 UK primary schools x
Harley A, et al.
[37]
2018
11–13 years x 248 1and half x x 4 4 8 public kindergarten x
Hermans R.C.J.
et al. [38]
2018
10–13 years x x 108 N.A. x x 1 1
Dutch children
(elementary school
children)—3 primary
school in the souther
part of Netherland
x
Piana N., et al.
[39]
2017
7–9 years x x 190 4 x x 4 4 11 primary school
classes in five schools x
Battjes-Fries
M.C.E., et al.
[40]
2017
10–11 years x x 1010 3 X X 1 1 children of 34
elementary school
grade 6 and 7 x
Bogart L.M., et
al. [41]
2014
N.A. 2997 41 x x 4 4 10 schools x
Shriqui V.K.,et
al. [42]
2016
4–7 years x 240 10 x x x 2 4 4 Children attending
LSES school classes x
Nutrients 2020,12, 2894 16 of 34
Table 3. Cont.
Author Year Age Age Coded Sample Size, n Time
Duration/Month Outcome Measures Effectiveness Among Children Target Group Target Group
Coded
Years EA EML EL Anthropometry HE/FV Nutritional
Knowledge Attitude Anthropometry HE/FV Nutritional
Knowledge Attitude S NS
Sharma S.V.et
al. [43]
2016
N.A. (first grade
students) x 172 24 x x 3 3
Public or charter
schools 1st grade
students and their
family members
x
Lawlor A.D. et
al. [44]
2016
9–10 years x
2221 (valid
data for the 10
mediators were
available for
87% to 96% of
participants
36 x x 1 1 primaryschool
children x
Steyn P.N.et al.
[45]
2016
Mean age 9.9 years x 500
intervention
and 498 control
36 x 1 primaryschool
children from low
income settings x
Jones M. et al.
[46]
2017
8–10 years x 2411 24 x x 4 4 schools engaged with
the Food for Life
programme x
Larsen L.A. et
al. [47]
2015 (fourth grade students)
average 9 years x 1713 2 x x x 4 4 3 47 fourth-grade
California classrooms x
Shen, Hu and
Sun [48]
2015
10.80 ±1.14 x 478 8 x x x 4 4 1 Twelve primary
schools in west China x
Gallotta C.M.
et al. [21]
2016
8–11 years x x 230 5 x x x 3 4 3
three primary schools
in the rural area in the
north of the city of
Rome (Italy)
x
Fairclough J.S.
et al. [49]
2013
10–11 years x x 318 6 x x 3 1 12 primary schools x
Cunha B.D. et
al. [50]
2013
10–11 years x x 574 9 x x 1 3 20 schools with fifth
grade classes x
Aviles O.A. et
al. [51]
2017
12–14 years x 1430 28 x x 2 3 20 schools x
Muros J.J. et al.
[52]
2013
10–11 years x x 54 2 x x 2 2
2 schools from rular
environment with
same socio economic
status
x
Moss A et al.
[53]
2013
N.A. 3rd grade
students 65 1 x x 3 4 3rd grade students x
Zota D. et al.
[54]
2016
4–11 years x x x 21261 12 x x x 3 4 3
students attending
both elementary and
secondary schools in
areas of low
socioeconomic status
(SES)
x
Nutrients 2020,12, 2894 17 of 34
Table 3. Cont.
Author Year Age Age Coded Sample Size, n Time
Duration/Month Outcome Measures Effectiveness Among Children Target Group Target Group
Coded
Years EA EML EL Anthropometry HE/FV Nutritional
Knowledge Attitude Anthropometry HE/FV Nutritional
Knowledge Attitude S NS
Gold A. et al.
[55]
2017
8–9 years x 662 12 x 4 3rd grade children
from 26 schools x
Mbhatsani
H.V.,et al. [74]
2017
9–14 years x x 172 6 x x 3 3
2 rural primary
schools with similar
socioeconomic
backgrounds
x
Hutchinson J.
et al. [57]
2015
7–10 years x x 1256 12 x x x 3 3 2 21 London schools x
Viggiano A et
al. [58]
2018
7–11 years x x x 1313 2.5 x x x 2 3 3 10 primary schools x
Waters E. et al.
[59]
2017
5–12 years x x x 2965 42 x x x 1 3 3
24 schools of Moreland
municipality x
Xu F et al. [60]
2015
Mean age 10.2 x 1182 10 x x 2 3 4th grade students
from 8 schools of
Nanjing, China x
Jung et al. [61]
2018
NA (elementry
school-kindergarden,
2nd, 3rd, 4th, 5th and
6th graders)
x x x 646 12 x x x 2 3 2 2 elementary schools x
Nutrients 2020,12, 2894 18 of 34
The information from abstracts were organized in a table with the following information:
Column A: Authors. The column lists the researchers/authors conducting the study.
Column B: Year. The column shows the year of the publication of the article.
Column C: Title/Reference. The column lists the title of the article.
Column D: Main aim. The column lists the main aim presented by authors in the abstract of
each article.
Column E: Main aim in brief. This column is a constructed variable that refers to the main aim of
each study. The idea was to give in brief the study idea and which outcome measures was focused on
in the study.
Column F: Program name. The column gives the name of the project, program or intervention
reported in in the article.
Column G: Location and Country. The column lists the specific place or location where the study
was performed.
Column H: Study design. The column shows research design of the study according to authors.
Column I: Study design coded. This column is a constructed variable to capture the research
design of the study and used to make an analysis of power possible, see Column J.
Column J: Power. The column was constructed to express the strength of the design. It is a dummy
variable that was assigned a numerical value that allowed for a quantitative analytical approach.
Column K, L and M: Intervention components. The column shows which intervention components
that was used in the study. We used a model that categorizes components into three different mechanisms
of influence: cognitive (K), environmental (L, M, N) and social (O).
The environmental component includes actions where availability of meals—or fruit and vegetable
(F & V)—were increased. Either through passive provision (F & V and meals) or through active
participation such as gardening. The social category included actions where families and/or peers were
actively influencing the participants. The cognitive category included teaching and learning.
Column L: Environmental/food focus on F & V. In this column, interventions which were targeted
towards fruits and vegetables were flagged. This includes interventions whose focus was providing
cooking lessons and maintaining healthy cafeterias during the intervention periods. Also, maintaining
healthy cafeteria here refers to school canteens providing healthy options to its menu where children’s
while buying food have healthier options to choose.
Column M: Environmental/food focus on increasing availability through school gardening. In this
column, interventions which provided free foods among participants through gardening within the
school were listed.
Column N: Environmental/food interventions focused on healthy meal availability. Interventions
which provided healthy meals, breakfast, snacks during the school hours and distributed fresh fruits
among the participants were listed in this column.
Column O: Family/social support. In this column interventions that included social components
were flagged. These interventions included peer and family influence mechanisms.
Column P: Age. The column lists the age of the targeted groups of the intervention expressed in
years according to the primary article data provided by authors.
Column Q: Age construct EA. This column shows a constructed variable for the age categorization
based on the primary data given by authors. The constructed code was made to make statistical
analyses possible. The construct Early Age (EA) was assigned if intervention were carried out in
early school.
Column R: Age construct EML. This column shows a constructed variable for the age categorization
based on the primary data given by authors. The code Early Middle Late (EML) was assigned if
intervention was targeted all age groups.
Column S: Age construct EL. This column shows a constructed variable for the age categorization
based on the primary data given by authors. The code EL refers to Early late and was assigned if the
intervention was targeted early and early and late school.
Nutrients 2020,12, 2894 19 of 34
Column T: Sample size. The number of young people enrolled in the intervention was listed in
this column.
Column U: Time duration. This column shows the length of the intervention expressed in months.
It is a constructed variable based on the primary data given by authors and was made to standardize
duration and make it ready for cross study analysis.
Columns V, W, X, Y: Outcome measures. In Columns T, U, V, W, the outcome measures named as
Anthropometry, HE/FV (healthy eating fruits and vegetables), Nutritional knowledge, and Attitude,
respectively, were listed according to our outcome model shown in Figure 1. Only a few include all
outcome measures, but all studies included at least one of them.
Nutrients 2020, 12, x FOR PEER REVIEW 15 of 29
Column T: Sample size. The number of young people enrolled in the intervention was listed in
this column.
Column U: Time duration. This column shows the length of the intervention expressed in
months. It is a constructed variable based on the primary data given by authors and was made to
standardize duration and make it ready for cross study analysis.
Columns V, W, X, Y: Outcome measures. In Columns T, U, V, W, the outcome measures named
as Anthropometry, HE/FV (healthy eating fruits and vegetables), Nutritional knowledge, and
Attitude, respectively, were listed according to our outcome model shown in Figure 1. Only a few
include all outcome measures, but all studies included at least one of them.
Figure 1. Outcome measures model. The figure illustrates the four types of outcome measures found
in the interventions.
Columns X, AA, AB, AC: Effectiveness. The effectiveness as measured by the outcomes
measured are listed in this column. Each outcome measure was rated using a Likert scale from 0–4.
The effectiveness of outcome measures among participants as measured by the measures in our
model (Figure 1): attitude, anthropometry, HE/FV, nutritional knowledge and attitude were listed in
the Columns X, Y, Z, AA, respectively.
Column AD: Target group. This column provides information on the target group of
interventions such as information on grades of subjects and municipalities.
Columns AE, AF: Target group. This column is a constructed variable created to capture if the
intervention had a special ethnic or socio-economic focus. Columns AC and AD consisted of coded
target group named as Standard (S) and Non-Standard (NS). The “NS” here represents the target
group either from refugees or immigrants or lower socio-economic classes.
Column AG: Keywords. This column lists the keywords found in the interventions.
Ordinary least squares regression was applied in this study; specifically, we used the linear
regression function in IBM SPSS 22. We opted for a multi-variate approach; i.e., multiple linear
regression was used. Anthropometry, behaviour (healthy eating and food focus), attitude and
nutritional knowledge were used as dependent variables. In order to better account for control
variables, such as sample size and study length, a dummy variable was introduced for study length
of one year and more; and a logarithm of the sample size was used instead of the actual sample size
to eliminate scaling effects. We grouped countries by continents (while splitting Europe into North
and South as there were enough studies and no countries in between) and introduced related
dummy variables. The remaining variables were used as independent variables without any
additional manipulations.
Since the aim was to create models consisting only of independent variables that significantly
influence the dependent variables, we used the backwards function. Because there were too many
independent variables for the backwards function for the attitude model (with only eight
observations), the stepwise function was used instead.
Figure 1.
Outcome measures model. The figure illustrates the four types of outcome measures found
in the interventions.
Columns X, AA, AB, AC: Effectiveness. The effectiveness as measured by the outcomes
measured are listed in this column. Each outcome measure was rated using a Likert scale from
0–4. The effectiveness of outcome measures among participants as measured by the measures in our
model (Figure 1): attitude, anthropometry, HE/FV, nutritional knowledge and attitude were listed in
the Columns X, Y, Z, AA, respectively.
Column AD: Target group. This column provides information on the target group of interventions
such as information on grades of subjects and municipalities.
Columns AE, AF: Target group. This column is a constructed variable created to capture if the
intervention had a special ethnic or socio-economic focus. Columns AC and AD consisted of coded
target group named as Standard (S) and Non-Standard (NS). The “NS” here represents the target group
either from refugees or immigrants or lower socio-economic classes.
Column AG: Keywords. This column lists the keywords found in the interventions.
Ordinary least squares regression was applied in this study; specifically, we used the linear
regression function in IBM SPSS 22. We opted for a multi-variate approach; i.e., multiple linear
regression was used. Anthropometry, behaviour (healthy eating and food focus), attitude and
nutritional knowledge were used as dependent variables. In order to better account for control
variables, such as sample size and study length, a dummy variable was introduced for study
length of one year and more; and a logarithm of the sample size was used instead of the actual
sample size to eliminate scaling effects. We grouped countries by continents (while splitting Europe
into North and South as there were enough studies and no countries in between) and introduced
related dummy variables. The remaining variables were used as independent variables without any
additional manipulations.
Since the aim was to create models consisting only of independent variables that significantly
influence the dependent variables, we used the backwards function. Because there were too many
Nutrients 2020,12, 2894 20 of 34
independent variables for the backwards function for the attitude model (with only eight observations),
the stepwise function was used instead.
Information and teaching was present in all but one study. Free food was found only in two
studies and focus on fruit and vegetables in three studies. Therefore, it is not surprising that neither of
the three variables were found to be significant in any of the models.
2.7. Study Sample
The search strategy resulted in 1826 titles which were screened for duplicates and potential
relevance. After this initial screening, 345 titles and abstracts were assessed against the inclusion
and exclusion criteria. Articles that studied school interventions after school hours were excluded.
In addition, articles which studied interventions among children in out of school context such as at
community level were excluded. The justification is that both “after school” and “out of school” since
can be regarded as non-typical school environments. We aimed to study the “school” as an artefact
that can be considered as a “standard” across countries despite some national differences. For both
“after school” and “out of school”, we argue that there are considerable differences among countries
and that an inclusion of such studies would negatively influence our analytical approach. In total,
42 articles
were identified as relevant and full papers were obtained as the final sample. Figure 2below
illustrates the search terms and selection process of articles.
Nutrients 2020, 12, x FOR PEER REVIEW 16 of 29
Information and teaching was present in all but one study. Free food was found only in two
studies and focus on fruit and vegetables in three studies. Therefore, it is not surprising that neither
of the three variables were found to be significant in any of the models.
2.7. Study Sample
The search strategy resulted in 1826 titles which were screened for duplicates and potential
relevance. After this initial screening, 345 titles and abstracts were assessed against the inclusion and
exclusion criteria. Articles that studied school interventions after school hours were excluded. In
addition, articles which studied interventions among children in out of school context such as at
community level were excluded. The justification is that both “after school” and “out of school”
since can be regarded as non-typical school environments. We aimed to study the “school” as an
artefact that can be considered as a “standard” across countries despite some national differences.
For both “after school” and “out of school”, we argue that there are considerable differences among
countries and that an inclusion of such studies would negatively influence our analytical approach.
In total, 42 articles were identified as relevant and full papers were obtained as the final sample.
Figure 2 below illustrates the search terms and selection process of articles.
Figure 2. Review flow chart. The figure shows the progress of the literature review process following
the PRISMA 2009 approach.
2.8. Intervention Study Characteristics
For all 43 items in our sample, Table 2 provides the information about the study, intervention
methodologies, characteristics strategies, etc. In our extract of studies, the sample size ranged from
65-2997 subjects/participants, and the intervention duration ranged from 1 and half month to 36
Figure 2.
Review flow chart. The figure shows the progress of the literature review process following
the PRISMA 2009 approach.
2.8. Intervention Study Characteristics
For all 43 items in our sample, Table 2provides the information about the study, intervention
methodologies, characteristics strategies, etc. In our extract of studies, the sample size ranged
Nutrients 2020,12, 2894 21 of 34
from 65-2997 subjects/participants, and the intervention duration ranged from 1 and half
month to 36 months. The systematic review locations identified by the author were: 26
from Europe
[21,36,38–40,44,46,49,52,54,57,58,63–75]
, six from Asia [
35
,
42
,
48
,
59
,
60
,
62
], 10 from
America [
37
,
41
,
43
,
45
,
47
,
50
,
51
,
53
,
55
,
61
] and one from Africa [
56
]. We categorized all interventions
according to their intervention components.
To this end
, we had constructed three classes: Information
and Teaching, Food Focus and Family/Social support as illustrated. The interventions characteristics of
each included study are shown in Table 2.
Of the total study sample, the majority of studies (n=41) involved “Information and Teaching”
components consisting mainly of classroom-based activities (e.g., an adapted curriculum and
distribution of educational materials, health and nutrition education program). Another 12 studies
along with “Information and Teaching” involved a food focus and availability component. These food
and availability components which consisted mainly of supervised school gardening, environmental
modifications to stimulate a more healthful diet, such as increased availability and accessibility of
healthy foods, distributions free food programmes, school provided free breakfast, school lunch
modifications and incentives. Only two studies combined all the three intervention components of
this study. Family/social support intervention was clearly focused on in nine study. In other studies,
even though their interventions were not primarily or secondarily focused on family/social support
component, they indirectly acknowledged the importance of parents and included them in their studies.
All of the reviewed studies included intervention components that were delivered in school
settings and within school hours. Our sample showed that consumption of fruit and vegetables
was the most used intervention component and was include in more than half of the interventions.
Most studies were designed and carried in a way where a research assistant was trained by senior
researchers/co-authors to ensure that each members of the research team followed same procedures
for data collection. Since all studies were “in situ” studies included a close researcher/school staff
cooperation component. In most of the listed studies, teachers being the responsible person to
implement the interventions were trained beforehand.
2.9. Types of Interventions
Table 2shows an overview of the programmes and their intervention components. From the
table, it can be seen that studies differed according to how broadly they intervened. Some studies have
included a narrow intervention (i.e., only one intervention components which targeted behavioural
components), whereas others included multicomponent approaches where all three intervention
components were used in the study.
3. Results
Finding the right approach to intervening for healthier eating at school is a major challenge.
In other words, which interventions create which impacts and how should the public best invest in
new policies, strategies, and practices at school if long term health is the intended end point?
The purpose of this review was to compile the evidence regarding the effectiveness of successful
school-based interventions in improving dietary behaviours, nutritional knowledge, attitudes and
anthropometry among children. The analysis of the data showed a number of relationships between
outcome effect and a number of other characteristics of the intervention (i.e., age, location/region,
intervention type, duration). Descriptive statistics are provided in Table 4.
Nutrients 2020,12, 2894 22 of 34
Table 4. Descriptive statistics.
NMinimum Maximum Mean Standard Deviation
Power 42 1.00 3.00 2.2619 0.91223
InfoAndTeach 42 0.00 1.00 0.9762 0.15430
FandV 42 0.00 1.00 0.0714 0.26066
FreeFood 42 0.00 1.00 0.0476 0.21554
AvailFood 42 0.00 1.00 0.1667 0.37720
FamilySocialSupport 42 0.00 1.00 0.2143 0.41530
EA—early age 42 0.00 1.00 0.3810 0.49151
EML—early middle late age 42 0.00 1.00 0.7381 0.44500
EL—early late age 42 0.00 1.00 0.5476 0.50376
SampleSize 42 54.00 21261.00 1464.2619 3277.18184
log10SampleSize 42 1.73 4.33 2.7904 0.54986
Months 41 1.00 112.00 14.6585 19.00245
YearOrMore01 41 0.00 1.00 0.4390 0.50243
AnthropometryScale 18 0.00 4.00 2.0000 1.13759
HEFVScale 36 1.00 4.00 2.5556 1.27491
NutritionalKnowledgeScale 26 1.00 4.00 3.1923 0.89529
AttitudeScale 9 1.00 3.00 1.7778 0.66667
The linear regression models carried out for each intervention component is added in the text
and the tables have been referred to each associated result. Out of 42 studies, 36 studies reported
the outcome on HE/FV behaviour scale while anthropometry and attitude impacts were observed in
18 and six studies, respectively. The item one of the results in this article presents the most general
finding from the literature review, item two describes the variable found significant in two cases, while
the remaining variables were significant in once case each. Additionally, item four, five and six are
related “design” phenomena effects in the sense that they are not related to intervention components
but to the study was designed your study. The rest is related to (intervention components rather than
designs. In Table 5, the outcome measures for which an effect could be seen has been listed. The linear
regression model describing what influences the attitude is provided in Table 6.
Table 5. Linear regression model for attitude.
Model
Unstandardized Coefficients Standardized Coefficients tSignificance
B SE Beta
(Constant)
FamilySocialSupport
EA—early age
1.250 0.177 7.071 0.000
1.000 0.395 0.500 2.530 0.045
0.750 0.250 0.593 3.000 0.024
Table 6. Linear regression model for anthropometry.
Model
Unstandardized Coefficients Standardized Coefficients tSignificance
B SE Beta
(Constant)
Power
AvailFood
YearOrMore
log10SampleSize
4.140 1.008 4.109 0.001
1.511 0.468 0.859 3.231 0.007
3.432 0.804 0.976 4.267 0.001
0.870 0.403 0.384 2.161 0.050
−2.437 0.503 −1.267 −4.846 0.000
With regards totheexplanatorypowerofthemodel, R
2
=0.789, R
2
adj. =0.719, and
significance =0.009
.
The linear regression model describing what influences the anthropometry is provided in Table 6.
With regards to the explanatory power of the model, R
2
=0.683, R
2
adj. =0.586,
and significance =0.003
.
The linear regression model describing what influences the behaviour is provided in Table 7.
Nutrients 2020,12, 2894 23 of 34
Table 7. Linear regression model for behaviour.
Model
Unstandardized Coefficients Standardized Coefficients tSignificance
B SE Beta
(Constant)
FamilySocialSupport
2.321 0.229 10.131 0.000
1.054 0.486 0.348 2.168 0.037
With regards to the explanatory power of the model, R
2
=0.121, R
2
adj. =0.096,
and significance =0.037.
An alternative linear regression model describing what influences the behaviour is provided in
Table 8.
Table 8. Alternative linear regression model for behaviour.
Model
Unstandardized Coefficients Standardized Coefficients tSignificance
B SE Beta
(Constant)
Neurope 3.227 0.205 15.761 0.000
−1.727 0.328 −0.670 −5.260 0.000
With regards to the explanatory power of the model, R
2
=0.449, R
2
adj. =0.432,
and significance <0.001.
3.1. School-Based Interventions in General Create Impact
Looking across the whole study sample, it can be seen that in general the interventions created
an impact in one or more ways either on knowledge, intentions, eating habits and/or anthropometry.
In other words, it was hard to find studies that created no impact. This finding adds to the body of
evidence that suggests that food-based interventions are a well-suited and effective policy tool when it
comes to promoting healthier eating among young people.
3.2. Family Support Affects Healthier Eating Behaviour and Attitude
Out of all the included studies, nine studies focused on family support as an intervention
component. But out of those, our analysis showed that the family involvement was impactful among
participants when it comes to promoting healthier food choices. Parents being influencers and role
models in the family in these studies seemed to help to influence children’s dietary habits. Studies
which involved participants’ parents in the intervention and provided them with nutritional knowledge
and healthy cooking skills (i.e., knowledge about the importance of healthy food and nutrition during
the early age of their children), seemed to be able to help young people prepare more healthy and
nutritious food at home. As studies showed, this seemed to increase children’s intentions towards
eating more fruits and vegetables and eventually resulted in consumption of more healthy foods.
However, this did not seem to be the case for all ages. Intention to eat more fruits and vegetables was
seen among early age participants (EA) either alone or with family support. It should be noted that
the regression models did not include interactions, since the number of analysed studies was only
~40. It was not possible to include age as a continuous variable in the models because (as it can be
seen in Table 5) age was a range, and sometimes even a wide range, e.g., 8–11 or 4–11. Family support
increases the outcome measure by approximately 1 in both cases. Please refer to Tables 5and 7for
detailed linear regression model used for attitude and behaviour.
3.3. Interventions Done in Northern Europe (7 Studies) Had a Smaller Impact on Behaviour than the Studies
Conducted in the Rest of the World (22 Studies)
The results from the models which was created to measure the efficiency of HE/FV highlighted
the fact that HE/FV scale depends only on region where the intervention was done. The behaviour
Nutrients 2020,12, 2894 24 of 34
outcome for Northern Europe was on average 1.5 while the average for the rest was 3.2 (please refer to
Table 8).
3.4. Effect of Anthropometry Measures Increases with Study Power
The results suggested that the design of the study plays a role when it comes to be able to show
impact of interventions. From the findings, it was clear that the anthropometry measured among the
participants were increasing with the power of the study. That is, the stronger the design the greater the
likelihood of being able to measure impact on anthropometric outcomes—a unit increase in the design
power is associated with an outcome increase of approximately 1.5 (please refer to Table 6). To examine
the influence of study design we used the score that was constructed for the purpose (please refer to
Table 1). This score assigns a higher power to randomized designs than non-randomized ones.
3.5. Study Duration Impacts Anthropometric Outcomes
It was also clear that the intervention duration does have impact on the outcome, i.e., the longer
the duration better the anthropometric results among the children. Interventions that lasted a year or
more, had the outcome measure on average almost one unit higher than shorter studies (please refer to
Table 6).
3.6. Larger Samples Impacts Anthropometry Measures
Results showed that anthropometric outcome decreased within the sample size. Increasing the
sample size by a factor of 10, from approximately 100 to 1000, decreased the outcome measure by
almost 2.5 (please refer to Table 6). Thus, bigger the sample size a reverse effect on outcome was
obtained. The studies whose intervention was done for long period of time (i.e., couple of months or
year and among small participants) were found to be effective in the outcome. It might be the case that
it was hard to administer the same thing to large sample size post intervention and thus could have
decreased the anthropometry outcome among the participants.
3.7. Food Availability Interventions Influence Anthropometric Outcomes
Our analyses showed that a food focus, specifically healthy meal availability had an impact on the
children’s anthropometric outcomes—increasing it by almost 3.5 on average (please refer to Table 6).
3.8. Interventions among Younger Students Influence Attitude Among Participants
Results showed that the younger the study subjects were, the more influence interventions had
on attitudes (the outcome was on average 0.75 higher than for other age groups). Thus, the result
suggests that the participants’ attitude increases when they are in their early age (EA) i.e., 4–7 years
old. Furthermore, results suggest that increased family support associated with participants’ attitude
towards healthy eating helps in changing the behaviour among them. Early age (EA) and family
support seemed to impact positively both alone and together. Meaning that the intervention had
positive impacts on participants (i.e., EA participants) attitudes towards healthy eating either with the
involvement of their family support or without the involvement of family support. Please refer to
Table 5for detail linear regression model for attitude.
3.9. No Effect of School Based Interventions on Nutritional Knowledge
Findings showed that nutritional knowledge among participants (i.e., of all age group) does
not depend on school-based interventions. Thus, none of the collected variables have influences on
nutritional knowledge.
Nutrients 2020,12, 2894 25 of 34
4. Discussion
4.1. Discussion of Results of This Review in Relation to Others
In the discussion we aim to relate our findings with what has been found in previous studies,
discuss our methodological approach and reflect on what are the policy implications. Since the
discussion on how to counteract the unhealthy eating pattern and the worrying increase in nutrition
related disorders among young people is attracting much attention and since the discussion on how
the school could contribute we aim to give policy makers and practitioners an up to date insight into
the potentials of the school to act as a hub for promotion of healthier eating and provide inspiration for
the development of new types of school-based interventions and strategies.
The huge interest in using the infrastructure of the school to initiate and promote healthier eating
among young people has resulted in a large number of interventions studies over the past decades.
This research interest per definition as the same time creates a need for syntheses of the findings in
order to make them feed into the public health and school policy cycle and to “send the results to
work”. Taken the huge investment that better food at school strategies at school will cost for states it
is worth appreciating that the Evidence-Informs-Policy pathway seems to be working. At the same
time the conceptual approaches and the understanding of what intervention components might work
better than others, which age groups might benefit the most etc. as developed considerably which
again adds to the rationale for synthesis of intervention study findings. Most recent reviews by Julie
et al. [
76
], Noguera el al. [
77
],
Evans et al. [78]
, Cauwenberghe et al. [
34
] and Brown et al. [
79
] has
created a time gap of almost five years. Covering the last five years of research our review makes a
needed contribution and in addition we argue it makes a needed contribution to a standardization and
conceptualization of both sampling and intervention design methodologies.
Overall, the findings from this review suggest that school-based interventions that include
intervention components such as information and teaching, food focus and family support are effective
in improving the HE/FV, anthropometric measurements and attitude towards healthy dietary behaviour
among the participants. On the other hand, nutritional knowledge among participants did not seem to
be influenced much by any of the intervention components used.
Impacts on HE/FV behaviours were observed, but mostly among early age children revealing
a distinct age pattern in the findings. Thus, age was seen as a significant factor in determining
effectiveness in several study [
35
,
37
,
39
,
42
]. Impact was greater on young children in the 4–7 year old
age range, suggesting that dietary influences may vary with age.
Multicomponent approaches that includes good quality instruction and programs, a supportive
social environment both at school and home, family support has been effective in addressing childhood
related diseases through focusing on diet and physical activity. Most of the studies in this review
implemented with combination of school staffand intervention specialists provide evidence for the
effectiveness of the program. Thus, evidence supports that family involvement and nutrition education
curriculum delivered by the teacher under supervision of intervention specialists can alter the intake
of fruit and vegetables while impacting positively on anthropometric measurements. Teacher led
interventions have been effective and can be the most sustainable approach for long term impact of
the program. The same conclusion was found in a review done in investigating the effectiveness of
school-based interventions in Europe which provided the effectiveness of multicomponent intervention
promoting a healthy diet in school aged children in Europe [
34
].Studies with a food focus in their
intervention approaches showed significant improvements in BMI [
35
,
54
,
58
]. Significant improvements
in BMI here refers to the studies whose probability value was less or equal to 0.05. This means that the
interventions in that case showed reduction in body mass of participants. We looked at studies whose
aim was to focus on interventions of obesity prevention or reduction among primary school children’s.
Thus, search term such as: “obesity prevention intervention among primary schools”, was used as
explained in the methods section. When performing the search for school-based interventions we did
not encounter any studies that were focusing on underweight. Making the options for healthy choices
Nutrients 2020,12, 2894 26 of 34
of food in the school cafeterias and having the option of free food from the school gardens decreases the
sugar sweetened beverages and junk options among the children’s and thus resulting in improvements
in BMI. This review evidence further highlights that duration of the intervention, i.e., a year or more
has an impact on anthropometric measurements. This is in contrast to reviews of Julie et al. [
76
] and
Cauwenberghe et al. [
34
] review that found that making the better options of food choices and duration
of the studies were effective in reducing the sedentary behaviour and noting improvements in BMI.
This study also found that larger sample sizes reverse the outcome of anthropometric measurements
(i.e., sample size negatively influences the outcome). This might be the case because it might be harder
to administer the same thing to more individual. Thus, more studies are needed to examine the effects
of bigger sample sizes.
Our study is far from being the first to create overview of the large number of studies that are
studying interventions that can promote healthier eating habits and that can counteract the worrying
increase in obesity and overweight among young people the general. The huge interest is reflected in
the number of studies trying to assess the impact and effectiveness of school-based interventions as
well as in the number of reviews aiming to synthesize the findings from the growing body of evidence
of the effect of school-based food interventions into actionable school food policies. Our study adds to
this body of knowledge and fills a gap since our study looks at the most recent studies.
Comparing our review with others we find that the majority of the studies on school food-based
interventions have been conducted in high income countries. This is also the case in our study and
this fact is important to keep in mind since it introduces a bias in the insight created from school
food effectiveness reviews. It is also important to keep in mind that studies—and as a result also
reviews-covers different types of school food cultures. These cultures can roughly be divided in
collective, semi collective and non-collective types. In the collective type found in countries such as
Sweden, Finland, Estonia and Brazil school food provision is an integrated—and mainly free—part
of the school day. In semi-collective approaches food is in most cases traditionally a part of what
is offered at school, but due to payment. In the non-collective approach found in countries such as
Denmark, Norway and the Netherlands there is little infrastructure and tradition for school organized
foodservice. In this approach parents organized lunch boxes as well as competitive foods traditionally
play a bigger role.
A further important note to make is the distinction between narrow F & V approaches and broader
healthier eating intervention approaches. This classification can also be seen in previous studies and
in more recent reviews. The first type of interventions that follow the six-a-day tradition that to
some extent has been fuelled by the European School Fruit program introduced by the EU in 2009
was reviewed by Noguera et al. [
77
] and by Evans et al. [
78
]. In a study by Noguera el al. [
77
] a
meta-analysis on F&V interventions was done but limited to educational interventions in the sense that
it only looked at computer-based interventions and covering mostly European research. The study
showed that this targeted but narrowed approach was effective in increasing FV consumption but
that broader multicomponent types of interventions including free/subsidized FV interventions were
not effective. In the review paper from 2012 by Evans et al. [
78
] examined studies done in United
Kingdom, United States, Canada, Denmark, New Zealand, Norway and the Netherlands. Evans and
co-workers [
78
] found that school-based interventions were able to moderately improve fruit intake
but that they had only minimal impact on vegetable intake. These reviews and previous ones generally
conclude that F&V targeted interventions are able to improve young people’s eating patterns towards
higher intake of fruit.
In the category of reviews taking a broader approach to healthier lifestyle promotion we find
studies and reviews that looks at promotion of healthier eating in general—and that in some cases
include physical activity. A review by Julie et al. [
76
] covered studies from United States, United
Kingdom, Australia, Spain and the Netherlands. This review also included physical activity as part of
broader school-based obesity prevention interventions. In particular, interventions should focus on
extending physical education classes, incorporating activity breaks, and reducing sedentary behaviours
Nutrients 2020,12, 2894 27 of 34
to improve anthropometric measures. Julie et al. concluded that interventions taking a broader
approach should include employing a combination of school staffand intervention specialists to
implement programs; that they should include psychosocial/psychoeducational components; involve
peer leaders; use incentives to increase fruit and vegetable consumption and should involve family.
In a study by Cauwenberghe et al. [
34
] intervention studies done in a European union studies were
reviewed. This review—as our study do—made an age distinction in the sense that a categorization was
done between children and adolescents. Among children the authors found a strong evidence of effect
for multicomponent interventions on fruit and vegetable intake. For educational type of interventions
Cauwenberghe et al. [
34
] found limited evidence of effect as found when looking at behaviour and
fruit and vegetable intakes. The study found limited evidence on effectiveness of interventions that
specifically targeted children from lower socio-economic status groups. For adolescents Cauwenberghe
et al. [
34
] found moderate evidence of effect was found for educational interventions on behaviour
and limited evidence of effect for multicomponent programmes on behaviour. In the same way as
our review authors distinguished between behaviour and anthropometrics and found that effects
on anthropometrics were often not measured in their sample. Therefore, evidence was lacking and
resulted in inconclusive evidence. Cauwenberghe et al. [
34
] concluded that there was evidence was
found for the effectiveness of especially multicomponent interventions promoting a healthy diet but
that evidence for effectiveness on anthropometrical obesity-related measures was lacking. In a review
by Brown et al. [
79
] studies mostly from Europe but also covering United States, New Zealand, Canada
and Chile it was found that intervention components most likely to influence BMI positively included
increased physical activity, decreased sugar sweetened beverages intake, and increased fruit intake.
Our review adds to the increasing support for the idea that school should play a role in promoting
healthier eating habits among young people. As such the school can be seen as an important actor when
it comes to the promotion of human rights. In particular; the right to adequate food, the right to the
highest attainable standard of health and right to the education, school plays an integral part which has
also been highlighted in the “United Nations System Standing Committee on Nutrition” new statement
for school-based and nutrition interventions [
25
]. Furthermore, Mikkelsen and colleagues [
80
] in their
study have also suggested the fact that the international framework of human rights should invoke its
strategies, policies, and regulations in the context of school and that national, regional, and local level
actors has important roles to play. Additionally, they have highlighted that ensuring healthy eating in
school environment can be a good investment in children short- and long-term health and education
achievements. Thus, schools, as a system have the potential to make lasting improvements in students
nutrition both in terms of quality and quantity and simultaneously contribute to realization of human
rights around the globe [25].
4.2. Discussion of Methods
Strengths and Limitations
All attempts to reduce complexity of research studies in a research field suffers from in built
weaknesses. Standardising the work of others in attempts to make generalizations is always difficult.
As per definition a review includes attempts to standardize its study material in order to create an
overview of “what works” and what “this that works” depends on. For obvious reasons research
protocols depends very much on the context of the study: What is doable in one study setting
on one country might not work on other settings. Additionally, reporting procedures vary among
authors. The aim of a review is to standardize this heterogeneity to something that is homogenous
and computable. So, in our case our constructs represent an attempt to make different studies with
similar but slightly different approaches and methodologies comparable by making them computable.
This has obviously some disadvantages.
Another limitation is that our review restricted itself to cover only published English language
articles. Therefore, publication bias cannot be excluded, as it is possible that the inclusion of unpublished