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53
Food advertising and television exposure: influence on eating
behavior and nutritional status of children and adolescents
SUMMARY. This study aimed to evaluate the influence
of food advertising and television exposure on
eating behaviour and nutritional status of children and
adolescents. It was a cross sectional study developed
among 116 students from a private school in Brazil.
Socio-demographic and health conditions were evaluated.
Anthropometric data, food consumption,
physical activity, television viewing habits and behaviour
in relation to food advertising were also investigated.
Among the results, a 1:2 relationship was
identified between the number of televisions and residents
per household. Excessive weight was present
in 25.8% of subjects and 66.4% of children watched
television while eating. Children were exposed to television
for a median of 3.0 hours daily (95% CI: 2.9
to 3.6). There was a direct association between attraction
to foods advertised and purchasing the product
(p<0.001) and a positive relationship between the
number of televisions per household and body weight
(r=0.246, p=0.015) and the amount of liquid consumed
during meals (r=0.277, p=0.013). Findings also
highlighted the association between watching television
while eating and the reduced probability of fruit
consumption (p=0.032), contrasted with a greater likelihood
of daily artificial juice intake (p=0.039). In
conclusion, watching television is associated with
lower probability of daily consumption of fruits and
the number of television at household is positively related
to BMI in children and adolescents.
Key words: Anthropometry, food consumption; food
publicity, television.
RESUMEN. Publicidad de los alimentos y la exposicion a la
television: Influencia sobre la conducta alimentaria y el estado
nutricional de los ninos y adolescentes. El estudio objetivo
evaluar la influencia de la publicidad de alimentos y la
exposicion a la television en la conducta alimentaria y estado
nutricional de ninos y adolescentes. El estudio es transversal con
116 estudiantes de una escuela privada en Brasil. Informacion
sociodemografica y de la condicion de salud fueron evaluadas.
Antropometria, el consumo de alimentos, practica de actividad
fisica, habitos de ver la television y el comportamiento en relacion
con la publicidad de alimentos tambien fueron investigados.
Entre los resultados, una relacion de 1:2 fue identificada entre
el numero de televisores por hogar y los residentes. El exceso
de peso estaba presente en 25,8% de los sujetos y 66,4% de ellos
veian la television mientras comian las refecciones. Los ninos
fueron expuestos a la television por un promedio de 3,0 horas al
dia (95% IC: 2,9-3,6). Se observo una asociacion directa entre
la atraccion de los alimentos anunciados y la compra del producto
(p<0,001) y una relacion positiva entre el numero de televisores
por hogar y el peso corporal (r=0,246; p=0,015) y la
cantidad de liquido consumido durante las refecciones (r=0,277;
p=0,013). Los resultados presento la asociacion entre ver la television
mientras se alimenta y la probabilidad de reduccion del
consumo de frutas (p=0,032), en contraste con una mayor probabilidad
de consumo de jugo artificial (p=0,039). En conclusion,
ver la television en demasiado se asocia con una menor
probabilidad de consumo diario de frutas y el numero de televisores
en el hogar se relaciona positivamente con el indice de
masa corporal.
Palabras clave: Antropometria, consumo de Alimentos, publicidad
de alimentos, television.
INTRODUCTION
The last decades were marked by an increase in the
occurrence of childhood and adolescent obesity in developing
countries, such as Brazil (1). This condition
is defined as multifactorial and is influenced by biological,
psychological, socioeconomic and environmental
factors (2). Among these, the role of television
exposure and food advertising with poor nutritional
content has been shown to contribute to excessive
weight gain and inappropriate food consumption (3).
Statistical projections show that if children and
adolescents were less exposed to food advertising
from 80.5 minutes per week (United States average)
Suzane Mota Marques Costa, Paula Martins Horta, Luana Caroline dos Santos.
Department of Physiology and Pharmacology, Institute of Biological Sciences, Federal University of Minas
Gerais, Belo Horizonte, MG, Brazil. Department of Maternal-Infant Nursing and Public Health, Nursing
School, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
ARCHIVOS LATINOAMERICANOS DE NUTRICION
Organo Oficial de la Sociedad Latinoamericana de Nutricion
Vol. 62 No 1, 2012
54 MOTA MARQUES COSTA et al.
to zero, which is not a feasible format to allow analysis
of the effect of these advertisements on the obesity
rate, the total food consumption by American children
and adolescents would drop by 4.5%. This reduction
represents a decrease of 0.38 kg/m2 in the body mass
index (BMI) average of this population and a decrease
in the prevalence of obesity among boys from 17.8 to
15.2% and in girls from 15.9 to 13.5%. In addition to
these estimates, some experts believe that these figures
could eventually drop to 11 and 9%, respectively (4).
Literature has also indicated that exposure to food
advertising corresponds to a greater likelihood of daily
consumption of sweets and soft drinks to the detriment
of fruit and vegetable consumption (5).
Considering the current debate over television exposure
and food advertising and their influence on
food intake and body weight, in addition to the facts
that a) during a period of one year, an individual is exposed
to more than 40,000 advertisements and b) food
industries spend around $9.6 billion in marketing their
products, of which $1.7 billion is specifically targeted
to children and adolescents (6), the present study
aimed to evaluate the influence of food advertising and
television exposure on the eating behaviour and nutritional
status of children and adolescents.
MATERIALS AND METHODS
Study design and sample
This was a cross-sectional study developed among
children and adolescents enrolled in a private school
in Belo Horizonte, Minas Gerais, Brazil. Three hundred
and fifty students were enrolled in the school,
who attended either in the morning (n=200) or evening
(n=150), and whose ages ranged from kindergarten
through high school.
A convenience sample was adopted. All children
and adolescents who were enrolled in elementary
school (n=250, 71.4% of total students) and answered
the questionnaire of data collection and whose parents
or guardians authorized their participation in the study
were included in the sample. This authorization was
obtained by signing a term of informed consent after
reading an explanation of the research objectives, measures
and information to be collected and the risks
and discomforts involved in the research, according to
the guidelines laid down in the Declaration of Helsinki.
The present study was approved by Research
Ethics Committee of the Federal University of Minas
Gerais under protocol number 091/09.
The age group from 7 to 15 years was studied, taking
into consideration that it is the group most exposed
to food advertising and television (7), in addition
to the fact that children under seven have more difficulty
understanding the advertising content (8).
Data collection
Data were collected by applying a self-administered
and self-explanatory questionnaire. Socio-demographic
and economic variables, levels of regular
physical activity and food consumption were evaluated.
Parents or guardians of children (7 to 09 years)
were given the task of answering the questionnaire,
and adolescents (10 to 15 years) responded to questions
by themselves.
Concerning socio-demographic and economic variables,
the sex and age of the students and the nature
of the family head (father, mother or other) and his/her
educational level were investigated. In addition, the
number of residents and televisions per household and
family income were also evaluated.
TABLE 1
Socio-demographic and economic
conditions of children and adolescents from
a private school in Brazil in 2009.
Socio-demographic
and economic conditions Frequency (%)
Sex - Female 67.2
Age group - Adolescent 72.4
Family head
Father 60.5
Mother 31.6
Other 7.9
Family head schooling
Elementary school 20.2
High school 37.7
Higher education 42.1
Family Income (R$)
.1,000.0 29.7
1,000.1-1,999.9 32.7
2,000.0-2,999.9 15.8
.3,000.0 21.8
FOOD ADVERTISING AND TELEVISION EXPOSURE 55
The respondents were also asked about their weekly
frequency of physical activity, time (in hours)
spent in physical activity per day and the place where
physical activity most commonly occurred (such as
school or home, for example).
Food consumption was investigated by applying a
Food Frequency Questionnaire (FFQ) and focused on
eating habits. The FFQ, which was qualitative and designed
specifically for this study, referred to the six
months preceding the |
interview and contained 14
types of food from different food groups, including the
most common products consumed by Brazilian children
and adolescents (9).
The evaluation of food habits included the number
of daily meals, self-perception of chewing quality,
drinking liquids during meals and characteristics of
school meals (packed lunch, purchased or not eaten).
As soon as students returned the questionnaire, it
was checked for data consistency. After verifying all
questionnaires, studentsf anthropometric data were
measured by two properly trained nutrition faculty
members from the Federal University of Minas Gerais.
The anthropometric evaluation consisted of measuring
weight and height to obtain BMI, according to
techniques described in the literature (10). This index
was classified according to studentsf age and sex,
adopting growth curves published by the WHO (11).
Television exposure and eating
behaviour in relation to food advertising
Television exposure and eating behaviour in relation
to food advertising was evaluated by applying
another self-administered and self-explanatory questionnaire.
This questionnaire included questions about
habits of television-watching, time (in hours) spent in
this activity and food intake concomitant with this
practice.
Additionally, the questionnaire included questions
about the habit of acquiring food advertised on television
and, if applicable, the main types of products purchased.
Finally, the attraction to a new food product
advertised on television and this acquisition were also
investigated by this study.
Data analysis
Food frequency consumption reported by the child
or adolescent was transformed to units of daily frequency
to obtain the probability of consumption of a
given food type in one day. For example, if the respondent
reported a food frequency consumption of
twice a week, this measure was converted into 0.29
(two divided by seven), representing a 29% chance of
consuming this product in a day. Similar transformations
were conducted for weekly and monthly frequencies,
keeping the ratings rare or non-ingestion (option
"never") intact. For those individuals who consumed
fruit daily, regardless of the amount, a 100% probability
of consumption was adopted.
Statistical analysis included Pearson and Spearman
correlations, simple Studentfs t-test, ANOVA, the
Mann-Whitney test and the Kruskal-Wallis test. These
analyses were performed using the Statistical Package
for Social Sciences (SPSS) 15.0 for Windows, Student
Version (2006). A significance level of 5%
(p<0.05) was adopted. The results were presented as
the mean (standard deviation) for variables with normal
distribution and as median (confidence interval -
95%) for others.
RESULTS
The sample consisted of 116 students (46.4% of all
students invited), with the majority being females
(67.2%), with a mean age of 11.6 (3.3) years. The table
1 presents all the other socio-demographic and economic
conditions evaluated. The median of residents per
household observed was 4.0 (CI 95%: 3.8-4.2) and
there were a median of 2.0 (CI 95%: 2.1-2.6) televisions
per household.
Physical activity was reported by 98.2% of children
and adolescents, and in 74% of cases it took place in
the school environment. In addition, students exercised
2.0 (95% CI: 2.3 to 2.7) times per week for 0.8
(95% CI: 1.0 to 1.3) hours at a time.
Regarding the anthropometric findings, 10.3% of
the students were underweight, while 25.8% were
overweight, and 12.9% were obese.
Food consumption data corroborate anthropometric
inadequacy, with 33.6% of students referring chewing
food poorly, 87.6% drinking liquids during meals
(250.0 mL, 95% CI: 212.1 to 256.9) and 66.4% consuming
food while watching television. Moreover,
there was a daily median number of 4.0 (95% CI: 3.9
to 4.4) meals.
As for feeding fractionation, 21.4% of students said
they did not eat meals at school, which corresponds to
56 MOTA MARQUES COSTA et al.
more than four hours of fasting. Among the students
remaining, 26.8% reported buying a snack at the
school canteen, and 48.1% brought meals from home.
An analysis of food consumption frequency revealed
a higher probability of daily consumption of sweets,
candies and chocolates compared to those
observed for vegetables. It is notable that there were a
percentage of students who never consumed vegetables
and fruits, but there was no such category for the
consumption of sweets, candies and chocolates, ice
cream or sandwiches (Table 2).
Watching television was practiced by the students
for a median of 3.0 (95% CI: 2.9 to 3.6) hours per day.
Additionally, 46.9% of children and adolescents reported
obtaining foods advertised in the television
media, and 54.9% were attracted by new products they
had seen advertised. As a result, 25% reported buying
food, and there was a statistically significant association
(p<0.001) between being attracted to a product
and purchasing it.
Analysis of the influence of food television advertising
on the eating behaviour and nutritional status of
the students showed a positive relationship between
the total number of hours spent watching television
and body weight (r=0.246, p=0.015) and the amount
of liquid ingested during meals (r=0.277, p=0.013)
(Table 3).
A positive relationship between the number of televisions
per household and the probability of daily consumption
of both artificial juice (r=0.277, p=0.029) and
beans (r=0.246, p=0.027) was also found (Table 3).
Moreover, we found that children and adolescents
who have the habit of eating while watching television
were less likely to consume fruits daily - 60% of students
who had this practice presented a 50 to 100%
probability of consuming fruits daily, whereas in students
who did not have this habit, the percentage was
74.3% (p=0.032). In contrast, the consumption of artificial
juices was more frequent for students who ate
while watching television - it was found that 45.7% of
children and adolescents who did not watch television
while eating consumed artificial juices rarely, in comparison
with 30% who had this habit (p=0.039).
With respect to food acquisition through television
advertising, those students who had this habit were
more likely (50 to 100%) to consume ice cream daily
in relation to others: 10.2% versus 3.6%, respectively
(p=0.033).
DISCUSSION
Among the results of the study, there was a high
prevalence of habitual television watching and a long
duration of this practice in a given day. Nutritional di-
TABLE 2
Probability of daily food consumption of children and adolescents from a private school in Brazil in 2009.
Food Probability of daily food consumption
100-75,1% 75-50,1% 50-25,1% .25% Rarely Never
Green vegetables 31.7 7.7 13.5 23.1 14.4 9.6
Other vegetables 36.3 4.9 11.8 28.4 10.8 7.8
Fruits 60.4 4.7 7.5 20.8 4.7 1.9
Milk 70.7 2.0 2.9 13.7 2.9 7.8
Dairy products 48.5 6.1 10.1 24.2 8.1 3.0
Beans 70.3 2.0 5.9 11.9 6.9 3.0
Processed meats 8.9 3.0 9.9 48.5 26.7 3.0
Sweets, candies and chocolates 42.3 1.9 12.5 33.7 9.6 0.0
Ice cream 5.8 1.0 6.7 69.2 17.3 0.0
Fried food 17.3 4.8 17.3 48.1 11.5 1.0
Sandwiches 2.8 1.0 2.8 60.4 33.0 0.0
Regular soft drinks 20.1 5.8 18.3 41.3 8.7 5.8
Natural juice 27.9 1.9 11.5 40.4 12.5 5.8
Artificial juice 28.6 5.7 6.7 23.8 25.7 9.5
FOOD ADVERTISING AND TELEVISION EXPOSURE 57
sorders and poor eating habits were also found in the
sample, which related to television exposure and food
advertising influence. These findings suggest the need
for intervention, which should be directed towards improving
the control of television advertising and reducing
the exposure of children and adolescents to
television.
This study describes the important role that television
exerts in the daily lives of Brazilian people, as a
1:2 relationship was identified between the number of
televisions and the number of residents. Moreover, the
median number of hours spent watching television we
observed, although similar to that seen in other studies
(5,12), was considered elevated according to recommendations
for Brazilfs population (13).
It is noteworthy that this study also found a positive
relationship between time spent watching television
and body weight. Weels et al. (14) previously reported
similar evidence in a cohort study conducted with
4,452 adolescents aged 10 to 12 years in Pelotas, Brazil.
However, in their study these authors observed a
contribution of television exposure on increases in
body fat and blood pressure (14).
The prevalence of nutritional disorders in the sample
exceeded the data verified for the Brazilian population
aged 10 to 19 years (15). One possible
explanation for the high prevalence of nutritional disorders
among children and adolescents under study
is their inadequate food intake, as evidenced by the
practice of unhealthy eating habits. We found inadequate
fractionation of feeding with omission of meals,
which results in lower consumption of healthy foods
(16). Furthermore, drinking liquids during meals and
chewing |
food improperly can promote excessive
weight gain because of a reduced stimulation of satiety
central controls (16,17).
Regarding this last habit, drinking liquid during
meals, students who spent longer periods per day watching
television also showed a higher intake of liquid
on these occasions. One possible explanation for this
TABLE 3
Relation between food advertising and television exposure and eating behavior and nutritional
status of children and adolescents from a private school in Brazil in 2009.
Variables Hours spent watching television Number of televisions
r p-value r p-value
Anthropometric variables
Weight 0.246 0.015* 0.101 0.310
Height 0.191 0.061 0.098 0.326
Body Mass Index 0.156 0.127 0.086 0.385
Number of daily meals -0.113 0.282 -0.101 0.327
Liquid ingested during meals 0.277 0.013* 0.190 0.080
Probability of daily food consumption
Green vegetables -0.171 0.177 0,205 0.082
Other vegetables 0.030 0.809 0.065 0.579
Fruits -0.106 0.330 0.013 0.906
Milk -0,15 0.194 -0.057 0.612
Dairy products 0.033 0.777 0.098 0.394
Beans -0.018 0.876 0.246 0.027*
Processed meats 0.059 0.652 -0.038 0.769
Sweets, candies and chocolates 0.077 0.498 0.105 0.336
Ice cream -0.181 0.122 0.071 0.545
Fried food 0.034 0.766 0.074 0.514
Sandwiches -0.100 0.439 0.099 0.443
Regular soft drinks -0.137 0.240 0.066 0.563
Natural juice -0.054 0.641 0.003 0,98
Artificial juice 0.230 0.094 0.277 0.029*
*p<0.05
58 MOTA MARQUES COSTA et al.
relationship might be frequent student exposure to scenes
of children and adolescents drinking beverages during
meals in cartoon food advertisements and other
television program commercials.
Another important habit observed in this sample is
eating while watching television. A study conducted
with 4,746 teenagers attending American public schools
observed that children who ate while watching television
had a lower intake of vegetables in general,
especially dark green and yellow vegetables, grains
and products high in calcium; this habit was also associated
with higher consumption of regular soft
drinks compared to those children who did not watch
television while eating(18). Similar findings were verified
by this study with regard to this habit and the intake
of fruit, artificial juices and ice cream.
However, the study found a relationship between
bean consumption and the number of televisions per
household. It may have been a function of the study
design bias and the fact that beans constitute a major
component of the Brazilian peoplefs daily diet(9).
This study also pointed to the relationship between
being exposed to advertisements of new products and
purchasing them. In this sense, food industries have
worked hard to attract consumers to the product long
enough to hold their interest in acquiring it. The use
of jingles is common in 35% of television food advertisements
and in the commercials is associated with
the use of 39% of cartoons and 42% of children consuming
the product (19).
Facing these problems, the Brazilian Ministry of
Health issued Resolution number 24, dated 15 June
2010, which laid down minimum requirements for
supply, advertising, publicity, information and other
related practices, that address the dissemination and
trade promotion of food and beverages containing high
amounts of sugar, saturated fat, trans fat, and sodium
and low nutritional content (20).
In addition to this type of approach, there is another
that has been undertaken by Escobar-Chaves et al.(21)
with childrenfs parents, aiming to reduce media exposure.
Families of 202 children from six to nine years
were recruited to participate in the study for a duration
of six months; 101 families constituted the study group.
Intervention consisted of a two-hour workshop and delivery
of six letters bi-monthly. The intervention proposed
to: 1) reduce the daily time spent watching
television, 2) turn off the television when nobody is watching
it, 3) not watch television during meals, 4) not
have television in childrenfs room; and 5) realize diversionary
activities not related to media vehicles. Among
the results, goals two, three and four were achieved to
a greater extent among the intervention group.
Despite its limitations, such as an adopted study
design, a reduced sample size (less than 50% of eligible
individuals of the study), the use of self-applied
questionnaires that was applied differently considering
age group, and the lack of assessment of caloric intake
and nutrients, this study describes the contribution of
television exposure and food advertising to increased
body weight and inappropriate eating habits among
students in a private school in Brazil.
ACKNOWLEDGMENTS
This study was sponsored by the Pro-Reitoria de
Pesquisa da Universidade Federal de Minas Gerais In
addition, there is no conflict of interest in this study.
Concerning the authorfs contribution, S.M.M Costa
and P.M. Horta participated in data collection, database
construction, statistical analysis, data discussion
and writing of the article. L.C. Santos participated in
project design, data collection coordination and article
revision.
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Recibido: 18-11-2011
Aceptado: 10-04-2012 |
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