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Obesity in children

By Kevin L. Joseph, Kong H. Ang, Khiem M. Ngo, Gregory F. Y. Yim

Internet publication: 4 March, 1996
Work by Monash University Medical students, produced as part of the health promotion subject offered at year three.
NB: Appendices are not available on the online version.

Joseph K, Ang K, Ngo K, Yim G. Obesity in children. Internet Journal of Health Promotion, 1996. URL:


This project was conducted to demonstrate that simple intervention techniques can be an effective approach towards reducing the prevalence of obesity in children and its related health problems. Fifth/sixth graders (n=67) and teachers (n=17) from a public primary school were identified as our target population. An educational seminar was conducted for teachers. An interactive session/talk and several activities were used to educate the children about the importance and methods of leading healthy lifestyles, and to serve as reinforcement sessions. Pre and post-intervention questionnaires and results from the activities were used to assess improvement in knowledge, intent to practice prevention (children only) and thus, the approach used. Teachers showed increases in knowledge about obesity (89%) and its prevention (92%). 97% of the children knew more and intended practicing healthy lifestyles. In conclusion, the approaches used were effective in improving knowledge and intention of practicing prevention - important steps towards reducing the prevalence of obesity in children.

Key Words:

Obesity, Children, Obesity - Prevention & Control, Obesity - Complications, Obesity - Epidemiology.

Health Issue

The purpose of this project is to demonstrate that approaches towards preventing the health issue - obesity in children - and its related problems at a community level, namely in a primary school, can be achieved through simple intervention techniques; and that these methods can be used to attain prevention at a population level. This report will define the health issue, the methods and strategies utilised in tackling this issue as well as evaluate the success of the intervention and provide recommendations for future programs.

Obesity is defined as an increase in body weight resulting from an excessive increase in body fat (1,2). Quantitatively, obesity is best determined using the Body Mass Index (BMI)*. According to this index, an individual is deemed as being obese if his/her BMI exceeds the cut-off point for his/her age. Below is the World Health Organisation's (WHO) recommended broad guidelines for determining obesity (3):

Age (years) BMI (kg/m2)
< 14 19-20
15 25
> 16 28

There are many factors that contribute to the development of obesity. These can be grouped into the non-modifiable and modifiable risk factors (4). In the former group, it has been shown that the incidence of childhood obesity increases with the number of biologically obese parents (4,5). Obesity is also seen more commonly in males (2,3), the lower socioeconomic group of society and individuals who have been obese as a child (4,5). Although these factors play an important role, it is the modifiable factors, namely dietary intake (energy input) and physical activity (energy expenditure), that are of greater importance in the development of obesity (4). A prolonged increase in fat intake and/or a reduced amount of physical activity (that is, an energy imbalance) can lead to obesity (2,4,5) and as such, it is these parameters that must be the target for prevention. It is important to note however, that obesity may primarily be due to reduced amounts of physical activity rather than increased fat intake (2,6).

The importance of prevention can be best demonstrated by considering the effects of obesity on health. Obesity has been associated with an increased risk of (2,4,5,7,9):

  • heart diseases (due to increases in serum cholesterol and blood pressure, and a decrease in high density lipoproteins (HDL) (7,8))
  • non-insulin dependent diabetes mellitus (NIDDM)
  • gallbladder disease and
  • cancers of the breast, colon, endometrium and prostate.

In addition, mortality rates from all causes at all ages are increased in the obese (10). Obese individuals often tend to have a low self-esteem and lead socially isolated lifestyles (11,12).

There is indeed cause for concern in Australia as approximately 50% of men and 33% of women are overweight or obese (8), and about 16% of adolescents are obese (3). Furthermore, recent studies have shown that too few people exercise regularly (8). This together with the ample supply of food, especially high energy foods (10), certainly encourage the development of obesity. Thus, it is imperative to actively promote prevention especially in children (11).

Priority Population Group

Teachers and children (in Grades 5/6) at Clayton South Primary School were chosen as the priority population. The fifth/sixth graders were further identified as being of primary interest based on the fact that 80% of obese adolescents become obese adults (3). By targeting this group, as they step into adolescence and become more autonomous (13), we hope to inculcate in them the importance of living healthy lifestyles* with the intention that they practice these and in doing so, prevent the onset of adolescent (11) and/or subsequent adult obesity. Although we realised the importance of intervening in lower grades, we felt that the fifth/sixth graders, being mature enough to understand the concepts and information to be presented, would be the most receptive group. Time constraints further restricted our involvement in other grades.

Teachers were included with the aim that once armed with enough knowledge about obesity and its prevention, they would subsequently educate their students over the years to come hence, enabling prevention to begin at as early an age as possible. Grade 5/6 teachers specifically would be able to reinforce our message and answer questions raised by their students during the post-intervention period. Additionally, teachers would also be able to identify children at risk of becoming obese and alert parents of this to avoid the development of obesity.

Parents were also identified as an important group as they often determine a child's food choices and amount of physical activity. Despite this, parents were not directly involved (although avenues were made available) as most parents at this school showed minimal interest in their child/children's schooling in the past.

Goals and Targets

The goal of this project is to reduce the prevalence of obesity in children, with the long term aim of reducing the prevalence of obesity in Australia. In order to achieve this, several targets were set to be achieved within the intervention period as follows:

  1. To increase teachers' knowledge and awareness about obesity, its associated health risks and prevention, placing emphasis on prevention during childhood.
  2. To increase, among children:
    • the knowledge and awareness about leading a healthy lifestyle, and
    • the practice of healthy lifestyles.

The different targets set for children were to accommodate for ethical issues, namely to avoid children labelling others as being obese.

Strategies and Methods

We began our project by approaching three public schools in Clayton as we felt that a public school would be more representative of the general population than a private school. Clayton South Primary School was then randomly selected for this project.

As our project involved both teachers and students, two different approaches were adopted.

Teachers' Program

  1. Pre-intervention questionnaire - this questionnaire was designed with the help of Dr. Frank Ng, our supervisor.
  2. Teachers seminar - a 45 minute seminar was conducted in which issues relating to obesity were discussed with particular emphasis on the weaker aspects of the teachers' knowledge. These included:
    • qualitative and quantitative definitions of obesity
    • the prevalence of obesity in children and society and the correlation between the two
    • the significance of childhood obesity, its causes and complications
    • preventative methods - maintaining healthy diets and increasing physical activity.

In addition, examples of approaches that could be used to encourage children to eat healthier foods were discussed. A copy of the seminar and supplementary visual aids (overhead projector and posters), utilised to improve presentation, are included in Appendix 1 and 2 respectively. A handout (Appendix 3) was also distributed prior to the seminar to aid understanding and for use as future reference. Finally, the teachers were briefed on Health Week with the intention that they would take this opportunity to teach their students about staying healthy.

Children's Program - Health Week

For ethical reasons, all references to obesity were avoided and healthy lifestyles were promoted instead.

  1. Promotion - in the week preceding Health Week, a banner and posters* depicting healthy foods and activities were placed around the school to capture the students' attention and interest.
  2. Pre-intervention questionnaire - this was designed with the help of Dr. Kenneth V. Jones (a senior lecturer in the Behavioural Sciences and Psychiatry Departments, Monash University). This questionnaire was distributed and collected before the children's talk.
  3. Children's talk (Appendix 4) - a 20 minute talk was given to each of the three Grade 5/6 classes. The children were told of the benefits of being healthy and then taught two methods of leading healthy lifestyles which were:
    • maintaining a healthy diet - the children were introduced to the food pyramid, the concept of grouping food into those that should be eaten most, moderately and least of, with the aid of posters and demonstrations with actual foods. Correct food habits, for example, eating a wide variety of foods were also discussed.
    • exercising - examples of exercises and methods of exercising were discussed while emphasising that exercise could be enjoyable and need not be strenuous.

As a precautionary measure, we stressed that excessive exercising and inadequate dietary intake could be detrimental to one's health and should be avoided.

  1. Art competition - the students were given four days to draw pictures depicting healthy lifestyles. Besides serving as a reinforcement, this competition enabled participation from the lower grades.
  2. Healthy Day - children were encouraged to bring healthy foods for recess to encourage future practice. Having joined them for recess, we later played games with them.
  3. Activities - three games (refer to Appendix 5, not available on-line) designed to be educational yet entertaining were conducted. This also served as a reinforcement session, an evaluation and inter-class competition.
  4. Prize-giving ceremony - the winners of the activities and art competitions were presented with a basketball and certificates-cum-synopsis (Appendix 6, not available on-line). Later, we presented all fifth/sixth graders with a synopsis to serve as a long term reinforcement. We also presented the school with a synopsis about obesity (Appendix 7, not available on-line).

Evaluation Plan

Two questionnaires - pre and post-intervention - were used to evaluate the extent to which our program achieved its targets (impact evaluation). The teachers' questionnaires (Appendix 8 and 9, not available on-line) were used to assess the level of knowledge about obesity (Q1-5, 7-9 pre-intervention; Q1,2,4 post-intervention). The pre-intervention questionnaire required answers to be selected from the choices provided while the post-intervention questionnaire consisted of a combination of scaled (1-5) ratings, Yes/No and open-ended questions.

For the children, the pre-intervention questionnaire (Appendix 10, not available on-line) was designed to assess food and exercise practices (Q1,4), preferences (Q2,3,5) and knowledge (Q6-9). A choice selection and Yes/No format was adopted. The post-intervention questionnaire (Appendix 11, not available on-line) aimed to assess knowledge acquisition (Q1,2,5). As the intervention period was too short to illicit any behaviour change, healthy lifestyle practices were evaluated based on intent (Q3). This questionnaire was kept simple and used a Yes/No format because:

  1. judging from the pre-intervention questionnaire, this format appeared to be less confusing hence, yielding better results
  2. it was to be completed within the normal school curriculum hours and as such simplicity was necessary to minimise interruption
  3. it was to be complemented by the evaluation of the activities (the food game and quiz) in which all the fifth/sixth graders participated. To improve the reliability of the results, participants were selected randomly
  4. the alternative option of reusing the pre-intervention questionnaire could have resulted in non-compliance and reproduction of answers as it had been completed before thus, rendering the results unreliable.

From this evaluation, most of the teachers were found to have a better understanding about obesity (88.9%) and its prevention (92.3%) following the teacher's seminar (refer to Figure 1). Among the children, 97% said that they had acquired new knowledge about leading healthy lifestyles (Table 5 and Figure 6). On the whole, 83% (refer Appendix 5) of the information that we had presented was retained while 97% of the children indicated intentions of practicing this knowledge (Table 5 and Figure 6).




Teachers generally had a poor understanding about obesity (58.4%) although their insight into prevention was much better (74.6%) (Appendix 12 and Figure 1). Many teachers failed to identify the importance of genetic factors and a lack of exercise in the aetiology of obesity (Table 1) although most correctly identified dietary factors as being of importance. Paradoxically, every teacher suggested increasing physical activity while only 29% cited reducing high energy food intake as a means of prevention. Many however, felt that stopping children from snacking would be preventative (Table 2 and Figure 2). These observations reflect their failure to identify:

  • obesity as being a disorder of energy balance
  • that both food and exercise affect energy balance and
  • that different foods contribute different amounts of energy.

In addition, more than half were not aware of the correlation between adolescent and adult obesity (Appendix 12, not available on-line). On the other hand, most teachers knew of the health risks associated with obesity with 94% selecting hypertension (Appendix 12, not available on-line).


Refer to Tables and Figures 3 and 4 for results.



The children had a good understanding (83.2%) (Figure 5) about leading healthy lifestyles although this figure is questionable. Most children correctly selected foods that most people know are healthy (such as fruits and vegetables) but 38% failed to identify fried chicken, a more vague option, as being unhealthy (Appendix 13). In addition, very few were actually leading healthy lifestyles (43%) and only 46.5% on average would have chosen to a healthy food or activity if given the choice (Appendix 13, not available on-line and Figure 5).


The children indicated that they would have liked more activities. This together with their interest to learn more indicates that edutainment approaches are the preferred learning methods for children. Refer to Table 5 and Figure 6 for further results.

Table 1:
Teachers' Pre-Intervention Questionnaire -
Causes Of Obesity (Q4)
Causes Number Percent
Lack Of Exercise 10 58.8
Excessive Eating 12 70.6
Increased Saturated Fat Intake 14 82.4
Genetic Causes 10 58.8
Increased Carbohydrate Intake 9 52.9
Increased Polyunsaturated Fat Intake 7 41.2


Figure 1: Teachers' knowledge of obesity and prevention

Table 2:
Teachers' Pre-Intervention Questionnaire -
Preventing Obesity In Children (Q6)
Prevention Number Percent
Less High Energy Food 5 29.4
More Activity 17 100
Appetite Suppressants 0 0
More Fruits & Vegetables 15 88.2
Crash Diet 0 0
Stop Snacking 10 58.8


Figure 2: Teachers' pre-interview knowledge of prevention (Q6)


Table 3:
Teachers' Post-Intervention Questionnaire (Q1,2,6)
Question 1 3 4 5
Seminar Content 0 % 84.6 % 15.4 % 0 %
Seminar Understandability 0 % 30.8 % 46.1 % 23.1 %
"Health Week" 0 % 46.1 % 38.5 % 0 %


Figure 3: Teachers' post-intervention questionnaire (Q1,2,6)


Table 4:
Teachers' Post-Intervention - Questionnaire (Q4,5,7)
  Response (Percent)
Question Yes No
Obesity Knowledge 76.9 23.1
Prevention Knowledge 92.3 7.7
"Health Week" Beneficial 76.9 3.1


Figure 4: Teachers' post-intervention questionnaire (Q4,5,6)


Table 5:
Children's Post-intervention Questionnaire (Q1-5)
Questions Response
Yes No
Number Percent Number Percent
Acquired New Knowledge 65 97 2 3
Enjoyed "Health Week" Activities 65 97 2 3
Try To Stay Healthy 65 97 2 3
Tell Others About Staying Healthy 57 85 15 15
Would Like To Learn More 66 98.5 1 1.5


Figure 5: Children's pre-intervention survey


Based on the results, we can conclude that this project has been successful in achieving its targets. This conclusion subsequently indicates that it is possible to improve knowledge about obesity and its prevention, either directly among teachers or indirectly among children, through the use of simple techniques such as seminars and edutainment activities. The intention to practice preventative measures was very high. This coupled with the elevated knowledge could improve the likelihood of practice in the future.

One must realise however, that the conclusions have several limitations. Firstly, the increase in knowledge could be simply be a result of the information still being fresh in the subjects' memory. This is possible as only a short time had lapsed between the intervention and distribution of questionnaires. Secondly, actual practice of prevention could not be determined due to the short intervention period. Thirdly, although intention to practice prevention among children was high, actual practice may not be improved mainly due to:

  • the possible lack of practising healthy lifestyle among parents
  • parents often determining their child's/children's food choices and exercise opportunities.

Finally, keeping these limitations in mind, the following recommendations may help improve the success of future projects:

  • increasing the duration of the intervention period for example, over a month, with more reinforcement sessions
  • beginning intervention at lower grades and earlier in the year
  • target parents for example through home visits, newsletters, community awareness groups etc.
  • conducting reinforcement programmes following the initial intervention
  • assessing knowledge and practice after a month, a year or five years.


We would like to acknowledge the following people for their guidance and help in our project:

  • Dr. Frank Ng, our supervisor, for his invaluable help throughout the duration of our project
  • Dr. Kenneth V. Jones for his advice in drawing up the children's pre-intervention questionnaire and approaches to change behaviour in children (used in the teachers' seminar)
  • Prof. M. Wahlqvist, Department of Medicine, Monash Medical Centre, for providing us with information regarding obesity
  • Dr. Bridget Hsu-Hage, the course convenor
  • Ms. Wendy McPhee and the Department of Community Medicine for help in preparing the synopses
  • the National Heart Foundation of Australia, Australian Dairy Corporation and Australian Nutrition Foundation for the posters which were used for promotion and during "Health Week".

We also extend our sincerest gratitude to the teachers and students (especially those from Grade 5/6) of Clayton South Primary School without whom our project would not have been possible. Special thanks also to Ms. E. Mulhern, the Vice Principal, who helped us organise and run our project in the school.


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