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Educational intervention on nutritional status and knowledge on diet and physical activity in school children


How to cite this article:
Benítez-Guerrero V, Vázquez-Arámbula IJ, Sánchez-Gutiérrez R, Velasco-Rodríguez R, Ruiz-Bernés S, Medina-Sánchez MJ. Intervención educativa en el estado nutricional y conocimiento sobre alimentación y actividad física en escolares. Rev Enferm Inst Mex Seguro Soc. 2016;24(1):37-43.

Educational intervention on nutritional status and knowledge on diet and physical activity in school children

Verónica Benítez-Guerrero,1 Imelda de Jesús Vázquez-Arámbula,1 Rogelio Sánchez-Gutiérrez,1 Raymundo Velasco-Rodríguez,2 Salvador Ruiz-Bernés,3 María de Jesús Medina-Sánchez1

1Unidad Académica de Enfermería, Universidad Autónoma de Nayarit; 2Facultad de Enfermería, Universidad de Colima. 3Unidad Académica de Nutrición, Universidad Autónoma de Nayarit. México

Correspondence: Veronica Benitez Guerrero

E-mail: veronica.benitez@uan.edu.mx

Date received: November 10th, 2014

Date judged: February 18th, 2015

Date accepted: May 20th, 2015


Introduction: Currently obesity at international, national and regional levels is an important part of a challenge to solve.

Objective: To evaluate the effectiveness of an educational intervention in the nutritional status and knowledge level about food and physical activity in school.

Methodology: Quantitative study, descriptive, cross-sectional, quasi-experimental. The sample consisted of 368 schoolchildren from 12 schools in the nutritional status. For the knowledge level the sample was 352 students, it was a simple random sampling using the formula for finite populations.

Results: The results showed that the educational intervention was able to reduce the rates of low birth weight but increased overweight and obesity. The prevalence of overweight and obesity was present in both male and females, it was 43.3 % before the intervention to 44 % post-intervention, manifesting mostly in boys than in girls. The T-tests indicated significant differences in the IMC in the control group and in girls in the study group, but no significant difference in the study group were found in children. The level of nutrition knowledge after the educational intervention increased proportionally by 83.59 % for the study group and 263.44 % in the control group.

Conclusions: The educational intervention can be effective in increasing knowledge of nutrition and induce children to significant changes in health habits. Greater parental involvement is suggested for best results.

Keywords: Nutritional status; Adolescent health; Physical education and training


Nutrition, over the course of life, has been considered one of the main determinants of health, physical and mental performance, and productivity; both insufficient and excessive nutrient intake have complex causes involving biological, socioeconomic, and cultural factors.1

Excess body weight is one of the most worrying public health challenges in the twenty-first century, because the prevalence of obesity has tripled in the last two decades. This increase in cases of obesity has led to WHO to determine this phenomenon as a global epidemic.2,3 In the pediatric population, the estimated prevalence of obesity is 2.7% and overweight is 7.6%; these average figures contrast with the report of the Encuesta Nacional de Salud y Nutrición (ENSANUT, 2012) yielding figures of 19.8% for overweight and 14.6% for obesity, with a combined national prevalence of overweight and obesity of 34.4% in children aged 5 to 11.4

In Mexico, as in other Latin American countries, the prevalence of malnutrition in children has increased; on the one hand, the malnutrition characteristic of developing countries continues to present itself, and on the other hand, increased overweight and obesity; this is due, among other factors, to imbalances in nutrient intake, either by excess or deficit, both due to imbalance between caloric consumption and expenditure.
Obesity is the main modifiable risk factor in the prevention of chronic noncommunicable diseases, cardiovascular diseases, and other complications. In the past three decades, its prevalence has seen an unprecedented increase and rate of increase in all ages and in all economic strata, including the poorest.5

The World Health Organization (WHO) reports that physical inactivity in adults has increased 14% over the past three years worldwide; this is the most important risk factor for mortality in Mexico, associated with the appearance and uncontrolled development of hypertension, diabetes mellitus, dyslipidemia, osteoporosis, and certain types of cancer.6 Therefore, the promotion of physical activity is recognized in the Acuerdo Nacional para la Salud Alimentaria (ANSA) as the first objective of a policy for overweight prevention and control at the national level.  

Several studies with different perspectives have addressed the issue of obesity and overweight in children, as well as the effects produced such as hypertension and diabetes,7 and their prevalence;8-11 other studies have documented results of intervention programs aimed at reducing overweight and obesity.12,13

The prevalence of nutritional problems in childhood shows that obesity, overweight, and malnutrition prevention strategies must start in the early years of life. Thus, the school age is an opportunity to take action to promote good nutritional status, as health-related behaviors are established during that stage that remain relatively stable the rest of life.14

Health education aims primarily to design intervention programs aimed at changing unhealthy beliefs, customs, and habits, and to promote, protect, and encourage health, to give people the means to improve health, requiring intervention from the institutions involved in addressing this public health problem.15

It is therefore necessary to change overweight and obesity and unhealthy lifestyles in the school population, which are the reflection of a complex web of cultural, economic, and biological aspects and family dynamics currently observed in societies. It is important to develop actions to promptly identify the determinants of nutritional status and to propose preventive care models supported by healthy lifestyles. The impact of intervening in this population will be reflected in future generations, as today’s child with good nutrition will be tomorrow’s healthy adult.

The purpose of this study was to evaluate the effectiveness of an educational intervention on nutritional status and level of knowledge about nutrition and physical activity in schoolchildren in the urban area of ​​Tepic, Nayarit, Mexico.


An intervention study was conducted on a sample from 12 public elementary schools in the urban area of ​​Tepic, the capital of Nayarit state, of which children in fourth and fifth grade were selected, of both sexes, between 9 and 11 years old. A raffle method was used to select schools, the sample size was calculated with the finite proportions formula, with a confidence level of 95% and a significance level of 0.05. The sample consisted of 368 students, 207 assigned to the intervention group and 161 to the control group.

The study was conducted in three phases: the first was diagnostic, to assess students’ nutritional status, measurements were made of body weight, height, and body mass index (BMI); the nutritional status of girls and boys was determined based on the Cartilla Nacional de Salud parameters with: Underweight (UW), Normal (N), overweight (OW) and obesity (O).

The weight and height readings were made without shoes and with uniform before the students left for recess; a Microlife-brand digital portable scale was used for weight, a mobile rod was used for height, and BMI was determined with both measurements. This stage used an instrument made for the purpose, structured into 6 categories related to food groups, macro and micronutrients, healthy food and junk food, general hygiene measures, beverages and liquids for proper hydration, and physical activity, to assess schoolchildren’s knowledge about eating habits and physical activity.

The second phase was intervention, in which two health education programs were developed with topics of nutrition and physical activity for the intervention group, and addiction prevention for the control group, each lasting three months.

In the third phase of evaluation, the instrument and weight, height, and BMI measurements were applied again, after the intervention.

The Statistical Package for Social Science (SPSS) version 18.0 for Windows was used. The analysis used descriptive and inferential statistics to characterize the population with frequencies, proportions, and measures of central tendency and variability. Student’s t-test was used in quantitative variables for dependent samples with significance level of 0.05. This test was applied for BMI in both girls and boys in the study and control groups.
The research adhered to the regulations of the Ley General de Salud16 in research, Article 14, informed consent letter signed by parents, authorized by the Secretaría de Educación Pública and the principals of the schools participating in the study.


Regarding the nutritional status of underweight and normal weight before the intervention, in girls it was 17% and 13% in the intervention group, while in the control group was 18.6% and 10%, respectively; in boys it was 10.1% and 16.4%, and 16.1% and 14.3% in the respective groups; overweight and obesity were found in the group of girls at 12.5% ​​and 8.2% in the intervention group and 9.3% and 7.4% in the control group. Boys predominated with overweight and obesity at 13% and 9.6%, and 14.3% and 10% in the respective groups.

After the intervention, the results show that girls in the study group managed to transition to a normal weight, decreasing underweight and overweight, reflecting a positive effect from the intervention. As for the boys, it shows that the percentage of underweight, overweight, and obesity increased, so the intervention had no effect on boys (Table I).

Table I. Nutritional status of schoolchildren of both sexes pre- and post-intervention
Groups Before intervention
Sex Underweight Normal Overweight Obesity
(n = 207)
F % F % F % F %
Female 35 17 27 13 26 12.5 17 8.2
Male 21 10.1 34 16.4 27 13 20 9.6
(n = 161)
Female 30 18.7 16 10 15 9.3 12 7.4
Male 26 16.1 23 14.3 23 14.3 16 10
After intervention
(n = 207)
F % F % F % F %
Female 28 13.5 34 16.4 24 11.5 17 8.2
Male 24 11.5 29 14 30 14.4 21 10.1
(n = 161)
Female 25 15.6 18 11.1 17 10.5 11 6.8
Male 22 13.6 24 14.9 26 16.1 18 11.1
F = frequency

Student’s t-tests for dependent samples confirmed that there were no statistically significant differences in BMI in boys (p > 0.05), but statistically significant differences were found in BMI from pretest to posttest for girls. For the control group, frequencies of overweight and obesity increased, and underweight decreased (Table I). Notwithstanding, t-tests confirmed that there were statistically significant differences (p < 0.05) in BMI for both boys and girls, as the analysis showed higher mean values ​​in the posttest than the pretest (Table II).

Table II.  Student's t-tests for dependent samples in relation to BMI by sex pre- and post-intervention
Groups Sex Before intervention After intervention p *
X1 S1 X2 S2
Study Female 18.88233 4.297684 19.97466 4.799672 0.000146
Male 19.86952 4.987991 20.23308 4.013103 0.232340
Control Female 18.84746 4.067575 19.97423 4.409601 0.000000
Male 19.47811 4.379648 20.64244 5.063563 0.000014
BMC = body mass index; X1 = median of pre-test; S1 = standard deviation of pre-test; X2 = median of post-test; S2 = standard deviation of post-test
* Calculated with Student’s t-test

Students’ knowledge pre- and post-educational intervention showed that their knowledge of nutrition and physical activity increased in both groups subsequent to the educational intervention; for the study group this was reflected in the levels of excellent (pre 4.4% and post 7.2%) and satisfactory (pre 31.5% and post 37%), and the control group significantly increased levels of satisfactory (pre 21.3% and post 42.1%) and sufficient (pre 25% and post 36.6%). Unlike the study group, in the control group the increase occurred naturally without intervention on the subject, suggesting that there may be other factors that reinforce this variable (Table III).

Table III.Schoolchildren’s level of knowledge of nutrition and physical activity (pre- and post-test)
Level of knowledge Groups
Intervention Control
Pre Post Pre Post
F % F % F % F %
Excellent 9 4.4 15 7.2 3 2.1 8 5.5
Satisfactory 65 31.5 76 37 31 21.3 61 42.1
Sufficient 69 33.1 61 29.4 36 25 53 36.6
Basic 33 16 30 14.4 31 21.3 15 10.3
Poor 31 15 25 12 44 30.3 8 5.5
F = frequency

According to the different categories evaluated in the instrument to measure students’ knowledge levels, the results indicate a positive effect of the intervention in both the experimental group and the control group, indicating that student knowledge increased about food groups, macro and micronutrients, healthy food and junk food, general hygiene measures, beverages and fluids, and physical activity (Table IV).

Table IV. Knowledge of schoolchildren by category pre-and post-intervention
Categories Study groups Pre-intervention p * Post-intervention
N1 X1 Mode S1 N2 X2 Mode S2
Food groups Study 207 18.04 19 4.86 0.010 207 19.28 24 4.78
Control 145 15.60 19 5.03 0.000 145 18.13 19 3.90
Macro- and micronutrients Study 207 15.34 16 3.98 0.014 207 14.39 16 3.89
Control 145 14.64 16 4.14 0.000 145 16.30 16 3.46
Healthy food and junk food Study 207 14.34 12 3.98 0.014 207 14.39 10 3.89
Control 145 14.64 12 4.14 0.000 145 16.30 10 3.46
N1 and N2 = number of data of pre- and post-test respectively; X1 = median of pre-test; S1 = standard deviation of pre-test; X2 = median of post-test; S2 = standard deviation of post-test
*Calculated with Student’s t-test


This study verified the nutritional status of schoolchildren through intervention, and also explored their level of knowledge about nutrition and physical activity.

Regarding the first objective of identifying nutritional status, we see that the highest percentages of students’ BMI in the study group were distributed among the categories of underweight, normal, and overweight at the ages of 9 and 10 years respectively, after the intervention. In the age group of 10-year-olds, percentages decreased in the categories of underweight and overweight, but obesity increased; something similar happened in the control group, in which the underweight and normal weight were steady, overweight decreased, but obesity increased. These data somewhat match with Olivares et al. (2007)17 and Loaiza and Atalah (2006),18 showing prevalence of overweight and obesity in children, although it is noteworthy that these studies did not make an intervention, but were more descriptive studies. Similarly, the results coincide with Encuesta Nacional de Salud y Nutrición (ENSANUT 2012)4 under the WHO criteria, which reports that there was an increase in obesity in the 5 to 11 age group. With regard to gender, a higher percentage of overweight (14.5%) and obesity (10.1%) was found in boys compared to girls (11.6% to 8.2%), similar findings to those reported by the Encuesta Nacional de Salud y Nutrición (ENSANUT 2012),4 indicating a percentage of 36.9% obese boys compared with 32% girls. They also agree with Gonzalez et al. (2011),8 reporting that the prevalence of overweight in girls was between 18.3 and 32.2%, and obesity between 4.5 and 15.1%, while in boys they reported a percentage of overweight between 10.9 and 26.1% and obesity 4.7 and 12.6%, respectively.

However, t-tests conducted by sex and study group established that the boys in the study group, apparently due to the intervention, did not show an increase in BMI unlike the girls and the control group. One can appreciate that the variability of the study group also decreases in boys, since most of the variability occurred in the control group (Table II). Notwithstanding, further studies should be conducted at different times to confirm the findings of this work. The BMI changes that the study presents, especially in girls after intervention, seem confounded by the difference found with boys. However, there are many factors that may have been involved in these differences, both physiological and behavioral changes and other factors affecting children of school age, which are outside the scope of our research and exceed the goals of this work. School age and adolescence are crucial stages for establishing eating habits and other lifestyles that persist into later stages, with repercussions (Aranceta, 2005).19

Finally, regarding the second objective of measuring the level of student knowledge pre- and post-educational intervention in relation to nutrition and physical activity, the results show that schoolchildren’s knowledge increased in both groups subsequent to the educational intervention, for the experimental group this was reflected in the levels of outstanding (pre 4.4% to post 7.2%) and satisfactory (pre 31.5% to post 37%), and the control group significantly increased levels of satisfactory (pre 21.3% to post 42.1%) and sufficient (pre 25% to post 36.6%). Unlike the control group, this increase occurred naturally, without intervention on the subject, suggesting that there were other factors reinforcing this variable, such as creating new healthy policies through strategies in schools, including contents of the curriculum of different subjects related to the balanced diet, good hydration practices, and others; also the creation of healthy school stores that promote the sale of healthy foods and eliminate junk food, and continuous and permanent physical activity as a measure to combat the sedentary lifestyle.  

The results indicate a positive effect of the intervention in both the experimental group and the control group in increasing student knowledge level in relation to: food groups, macro- and micronutrients, healthy food and junk food, general hygiene measures, beverages and fluids, and physical activity.

In this regard, these results agree with Valdez et al. (2008)20 that educational intervention does increase knowledge in the various areas addressed by improving self-esteem and practices related to food, but they also differ because the dietary practices of the students in this study show no relation to their nutritional status due to weight gain towards obesity.

These facts are of great importance to generate other studies to address factors other than lack of knowledge that can determine the nutritional status of schoolchildren. Among these we could mention the lack of parental modeling of proper nutrition, family routine, economic and social factors, and low motivation of parents to promote physical activity in their children.


Regarding nutritional status, it was observed that the educational intervention made in children ages 9 to 11 managed to reduce the rate of underweight, however overweight and obesity increased. The prevalence of overweight and obesity was 43.3 to 44.4% in both genders, manifesting itself more in boys than in girls.

Our results show that an educational intervention may be effective to increase knowledge and understanding of the importance of a balanced diet and physical activity, which, even without showing a positive change in nutritional status, can induce significant changes in the short- and long-term health habits of children this age, and may also help reduce the risk factors of chronic degenerative diseases.


The researcher professors of the Unidad Académica de Enfermería of the Universidad Autónoma de Nayarit thank the Asociación Regional de Facultades and the Escuela de Enfermería de la Zona Pacífico, for their technical support, and the Unidad Académica de Enfermería of the Universidad Autónoma de Nayarit for the technical and financial support and facilities provided to execute this study. We also appreciate the participation of the students of the public primary schools in the state of Nayarit. 

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