Is brand visibility on snacks packages affecting their consumption in children? Results from an experimental ad-libitum study

Dario Gregori, Giulia Lorenzoni, Simonetta Ballali, Maria Gabriella Vecchio, Elvira Verduci, Paola Berchialla

Abstract

The aims of the study were to assess the effects of the brand when snacking in children 6-11 years old and to evaluate the effect of different levels of brand awareness on children’s intake. A 3x2 factorial design was adopted, and 96 children were randomized based on their brand awareness scores, assessed using the IBAI instrument and the study was conducted over two experimental sessions. First, 11 snacks were presented to the half of children laying on their own branded packages, whilst to the other half unbranded. In a second afternoon break, on a different day, the condition of branded/unbranded was crossed-over. Children were randomized in three groups based on combinations of concomitant TV and advertising exposure. Caloric intake (Kcal) of snacks eaten during sessions was taken as the main study outcome. No significant differences in energy intake were recorded according to brand visibility, both in children with high and low brand awareness. Exposure to TV and advertising showed no significant association with energy intake in the different groups and with the likelihood of being a high consumer. The present study suggested that brand visibility did not promote a higher caloric intake in 6-11 years old children during a snacking occasion.

Key words: Food brand, snacking, advertising, ad libitum, brand awareness, caloric intake.



¿La visibilidad de la marca en el empaque afecta el consumo en los niños? Resultados de un estudio experimental ad libitum

Resumen

Los objetivos del estudio fueron el evaluar los efectos de las marcas comerciales durante una merienda en niños de entre 6 y 11 años de edad, así como analizar el efecto de diferentes niveles de conciencia de marca en el consumo de los niños. Se utilizó un diseño factorial 3x2, y se asignó al azar a 96 niños según sus puntuaciones de conciencia de marca, que fueron evaluados mediante el instrumento IBAI. El estudio se realizó en dos sesiones experimentales. En primer lugar, se presentaron 11 bocadillos (alimentos), a la mitad de los niños colocando en sus propios paquetes de marca, mientras que a la otra mitad sin marca. En un segundo recreo de la tarde, otro día, se realizó un cruce en la condición de bocadillos de marca y sin marca. Los niños fueron asignados al azar en tres grupos, según combinaciones concomitantes de exposición a la televisión y a pautas publicitarias. La ingesta calórica (Kcal) de bocadillos consumidos durante las sesiones se adoptó como principal resultado del estudio. No se registraron diferencias significativas en el consumo de energía dependiendo de la visibilidad de la marca, ni en los niños con un alto o bajo reconocimiento de marcas. La exposición a la televisión y a la publicidad no mostró una asociación significativa con el consumo de energía en los diferentes grupos y ni con la probabilidad de ser un gran consumidor. El presente estudio sugiere que la visibilidad de las marcas no promueve una mayor ingesta calórica en niños de entre 6 y 11 años de edad en el contexto de una merienda.

Palabras clave: Marca de alimentos, refrigerio- colación, publicidad, a gusto, conocimiento de la marca, ingesta calórica.


Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Italy. ZETA Research Ltd, Trieste, Italy. Department of Health Sciences, San Paolo Hospital, Pediatric Clinic, University of Milano, Italy. Department of Clinical and Biological Sciences, University of Torino, Torino, Italy.

Introduction

The growing prevalence of overweight and obesity in children has gathered an extensive interest from the scientific community (1), shifting from an initial analysis dedicated to assess the present situation and its outcomes toward a broader research targeting potential risk factors involved in its development and maintenance. The increase in childhood and adolescent obesity is leading to adverse health outcomes in the short and in the long term (2, 3), since it is deleterious to individual health, and it also results in a rising cost for the public sector.

The multifactorial network characterizing obesity determinants has frequently been mentioned, in order to broaden research towards a complex scenario taking into account mutual influences and relationships (4, 5). Each node of this net is characterized by different factors, that are modified, switched, and triggered by several macro structures, like genetics, behavior, built and social environment.

Among various factors identified as possible causes for the increase of children’s obesity, television viewing and advertising aimed at children are among the most important factors that have been linked to a reduction in physical activity and an overconsumption of food high in fat and sugar (6, 7).

The mechanism is etiologically grounded on the lower caloric expenditure associated with TV viewing and the increased caloric intake due to TV-generated distraction and snack advertisements. In addition, recent studies have pointed out that, especially in overweight and obese children, preference for high carbohydrate and high fat foods is enhanced in children who are exposed to the greatest amounts of televisual media (8). Experimental studies in adults suggest that focusing attention on watching TV or listening to music while eating may disrupt the ability to regulate energy intake and promote overeating (9, 10). Similar associations were found in children, showing a positive association between TV viewing and childhood obesity (11, 12), but they failed to describe the mechanisms underlying these results. Costa showed the inverse association between screen time and daily consumption of fruits, concluding that the number of television in a household is positively related to BMI in children and adolescents (13).

Literature provides such heterogeneous results referring to the impact of food advertising on children’s food consumption (14). The effect of advertising and its interaction with brand visibility during afternoon snack time has not been yet jointly investigated. Indeed, afternoon snacking has not been very much studied, and its effects, both in terms of nutrient composition and caloric intake, on dinner eating habits or its impact on after-school physical activity are still not entirely known (15).

The primary aim of the present study was to assess the effect of having brands displayed in food packaging on children’s eating behavior during an afternoon snack time. The secondary objective is to evaluate the effect of different levels of brand awareness on children’s intake. By design, TV viewing and brand advertising (displayed both on food package and on TV commercials) were taken into account as potentially intervening factors and balanced during randomization.

Materials and methods

Design

The present study was a randomized, 3x2 factorial experimental study. For logistic purposes, the study was organized in three steps: assessment of brand awareness (Step 0), evaluation of brand visibility on children’s caloric intake (Step 1), repetition of Step 1 by crossing over the condition of branded/unbranded visibility (Step 2).

In Step 0 children were selected by means of the score reported from a modified version of the original IBAI questionnaire (16), assessing brand awareness. The total sample was then divided into two groups, one included high brand awareness (characterized by a total scoring ≥40 points) subjects, and the other, a low brand awareness (< 40 points) ones. Furthermore, each group was further assigned to one of three different conditions of TV exposure (No TV, TV, TV + advertising), resulting in 6 factorial combinations. In each category, the resulting 12 children were stratified for brand awareness, age, and gender (Table 1) and finally randomized to brand visibility. In summary, the experimental study developed in Step 1 had a 2x3 (Brand Visibility x TV and advertising exposure) full factorial design, blocked by age (two groups 6-8 and 9-11 years old), by gender (male and female) and by brand awareness. Specifically, the first factor was TV exposure, organized in 3 different levels: no TV exposure, exposure to cartoons, and exposure to cartoons and advertisements. The second factor was the presence of the brand on the snacks given to children, and was organized in two levels: presence of the brand (branded), absence of the brand (unbranded).

TABLE 1. Sample stratification according to age, gender and brand awareness. Mean Brand Awareness scores, with SD in brackets.
TABLE 1. Sample stratification according to age, gender and brand awareness. Mean Brand Awareness scores, with SD in brackets.

Step 2 was carried out equally to Step 1, but inverting the brand level in the two groups (branded snack were given to the subsample that had received an unbranded snack in Step 1, and vice versa).

Participants

Ninety-six children between 6 and 11 years of age were selected to have high and low level of brand awareness. Children were recruited as equally distributed by gender and age: fortyeight 6-8-year-olds (24 female) and fortyeight 9-11-year-olds (24 female). Children with cognitive disorders or metabolic diseases or allergies to the products offered during the experimental session were excluded. Parent informed consent was obtained for all children prior to each child’s participation in the study. Children’s participation followed the guidelines and ethics issued by APA (17). Parents were asked not to provide snacks to children in the hours before the experimental sessions.

Sample size

The sample size of 96 children was computed with reference to an alpha equal to 0.05 and a power of 0.90, which aimed at detecting at least a difference of 20 Kcal of caloric intake (assuming an equal standard deviation in the two groups of approximately 30 Kcal) between the two groups of Brand Visibility in each of the 8 randomization cells (Age x Gender x Brand Awareness).

Experimental procedure

  • The preliminary phase of this study (Step 0) involved sample recruitment and stratification. The sample consisted of children between 6-11 years (children attending primary school).
  • Children were selected on the basis of their level of brand awareness assessed by means of the IBAI (Italian Brand Awareness Instrument (16); a logo-matching exercise, consisting of 30 pictures representative of food brand logos) and they were equally divided into high and low brand awareness groups.
  • The experiment was characterized by two experimental sessions separated by a 2-week period (Step 1 and Step 2), in which parents were asked to bring their children to the laboratory during two afternoon breaks. The project flow is presented in Figure 1.
  • FIGURE 1. Project flow.
    FIGURE 1. Project flow.
  • In Step 1, 11 snacks were placed on a tray, laying on their own branded packages, for half of the sample, whilst the other half of the children received a neutral tray (unbranded).
  • After 2 weeks period, Step 2 was performed and the condition of branded/unbranded was inverted for the same two subgroups of the sample. The snacks utilized in the experiment were Kinder Frutti©, Ferrero Brioss Albicocca©, Kinder Brioss Latte©, Kinder Delice©, Mulino Bianco Flauti Latte©, Mulino Bianco Flauti Albicocca©, Mulino Bianco Pan Goccioli©, Mulino Bianco Saccottino Albicocca©, Mulino Bianco Pan di Stelle©, Kinder Yogo Brioss©, Mulino Bianco Plum Cake©. Snacks included: cocoa biscuits (Mulino Bianco Pan di Stelle©); individually packaged soft pastries with apricot jam (Kinder Frutti©, Ferrero Brioss Albicocca©, Mulino Bianco Flauti Albicocca©, Mulino Bianco Saccottino Albicocca©, Kinder Yogo Brioss©), milk cream (Kinder Brioss Latte©, Mulino Bianco Flauti Latte©) and chocolate chips (Mulino Bianco Pan Goccioli©); individually packaged soft sponge with cocoa cream topping and filled with milk cream (Kinder Delice©); individually packaged miniplum cakes made with yogurt (Mulino Bianco Plum Cake©). Children’s preferences towards these snacks were not investigated.
  • The two groups of children characterized by different brand awareness (high and low brand awareness) were randomized into 3 groups based on TV and advertising exposure: No TV, TV, TV and advertising. Within the “TV” subgroup, younger children watched a 16 min. episode of Disney© Lion King, while the older ones watched a 16 min. episode of Marvel© Spiderman. The advertising utilized in the third subgroup was embedded within the movies and consisted in 7 spots lasting for 3 minutes, referred to the products that children had on the tray they were facing.

    All children were asked to eat ad libitum and to choose the snacks they preferred, being given 16 minutes from their first bite.

    All the snacks were weighed with a highprecision balance before and after each session, in order to quantify the amount of snack not eaten, therefore estimating energy intake of each child.

    Measures

    Socio-Demographic variables

    Before the starting of the experimental session, parents were interviewed by the investigators in order to assess demographic parameters, children’s health status, behaviors, frequency of food consumption, food habits, physical activity, daily lifestyle (sleep, TV viewing, after- school care, etc.).

    IBAI questionnaire

    Food images represented in the 30 flash-cards of the IBAI were shown to the children (16), interviewing them on food images’ brand and product names and subsequently on the correct matching of each logo with the right food, between four choices of foods.

    At the end, the interviewer asked the child on the specific name of the product. Brand Awareness Scores (IBAI-score) could range from a minimum of 0 to a maximum of 90, with a cutoff set at 40 points which was used to define the two groups: low brand awareness children (<40) and high brand awareness (≥ 40) (16).

    Snacks weighing

    At the beginning of the study, every snack was assigned with a specific code and was weighed in order to record these data in the software used for the study. At the end of every session, each snack the child had had was weighed once again in order to calculate the difference in terms of eaten products. All weights were collected by means of an Acculab© precision weighing scale with the capacity of 510g of and 0.1g readability.

    Statistical analysis

    A basic exploratory data analysis was performed on the sample and it was reported using the median (I-III quartile) for continuous variables and the percentages (absolute numbers) for categorical variables, as appropriate.

    The main analysis has been based on a linear model for caloric intake where the blocking factors (i.e., Gender, Age in two classes according to the randomization procedure, and Brand Awareness) have been forced to stay in the models. Repeated measurements were taken into account using the sandwich estimator of Huber-White (18, 19). Specific investigations on single factor-level effects have been conducted using appropriate linear contrasts.

    To check for additional confounding factors, a further model, in addition to the base one has been developed, performing a selection among the candidate variables using the AIC criterion in the backward fashion, still forcing the inclusion of the design variables in the model.

    In addition, children were identified as “high consumers” if their caloric intake during the experimental session exceeded the top quartile of the observed distribution. The variables related to the probability of being a high consumer were modelled using a logistic regression model, again using the Huber-White estimator for accounting for repeated measurements, and selected via the AIC criterion in a backward fashion.

    The analyses have been performed using the R System (20).

    Results

    Ninety-six children were assessed using the IBAI questionnaire and were selected to participate to the following phases, equally divided by age (6-8 and 9-11 years), gender, (male and females) and brand awareness score. They were unselected for overweight or obesity. The highest median brand awareness score was retrieved in older males (47.00), while the lowest was measured in the younger female group (26.58).

    Sample characteristics (assessed by children questionnaire), in accordance to brand visibility and also to TV exposure (no TV, only TV, TV+advertising) are summarized in Table 1 along with their main characteristics in Table 2.

    Comparing the caloric intake of the three groups of children (no TV exposure, only TV
    TABLE 2. Description of the sample. Summaries for categorical variables are expressed as percentage (absolute numbers in parenthesis) and for continuous variables as I quartile / median / III quartile.
    TABLE 2. Description of the sample. Summaries for categorical variables are expressed as percentage (absolute numbers in parenthesis) and for continuous variables as I quartile / median / III quartile.
    TABLE 2. Description of the sample. Summaries for categorical variables are expressed as percentage (absolute numbers in parenthesis) and for continuous variables as I quartile / median / III quartile. (cont.)
    TABLE 2. Description of the sample. Summaries for categorical variables are expressed as percentage
(absolute numbers in parenthesis) and for continuous variables as I quartile / median / III quartile. (cont.)

    exposure, TV+advertising exposure) when both snacks were branded and unbranded, no significant differences were recorded (Table 3), neither in Step 1 and Step 2. Despite no significant differences, we found out that, in the group of non-visible brand (Step 1), children not exposed to TV presented an intake of 100 kcal higher than those exposed to TV+spot.

    TABLE 3. Energy intake in the experimental grid, expressed as mean Kcaloric intake. SD is given in brackets. No significant differences observed.
    TABLE 3. Energy intake in the experimental grid, expressed as mean Kcaloric intake. SD is given in brackets. No significant differences observed.

    Referring to the multivariable model, even after adjustment for potential confounders, we showed no significant association between increased caloric intake and Brand visibility (Table 4).

    TABLE 4. Multivariable model to assess the association between caloric intake and other parameters recorded with children questionnaires.
    TABLE 4. Multivariable model to assess the association between caloric intake and other parameters recorded with children questionnaires.

    Figure 2 and Figure 3 report the trends among the two brand awareness groups of total grams intake in children, exposed or not exposed to TV viewing. Children reporting high brand awareness and not exposed to TV showed lower snacks intake when brand was not visible (Figure 2), while children exposed to TV+advertising showed the same snacks intake when both the snacks were branded and unbranded, this probably because of children’s prior preferences towards the snacks, even if we did not investigate them. Additionally, among children with low brand awareness (Figure 3) exposed to TV and TV+advertising, the snack intake was lower when the brand of the snack was visible, this could be related to the fact that TV and TV+ advertising exposure was distracting.

    FIGURE 2. Trends of energy intake among children of the high brand awareness group, exposed or not exposed to TV viewing and package’s brand.
    FIGURE 2. Trends of energy intake among children of the high brand awareness group, exposed or not exposed to TV viewing and package’s brand.
    FIGURE 3. Trends of energy intake among children of the low brand awareness group, exposed or not exposed to TV viewing and package’s brand.
    FIGURE 3. Trends of energy intake among children of the low brand awareness group, exposed or not exposed to TV viewing and package’s brand.

    High consumer

    The top quartile of energy intake corresponded to 319 Kcal. This value has been chosen as the cut-off to identify the subgroup of 21 children with higher energy intakes during the experimental session in order to investigate factors associated to higher energy intake in this snacking occasion. Table 5 shows the main characteristics of these “high consumer” children. At the multivariable analysis, no significant association was found for the experimental factor TV (p-value 0.251), Brand Visibility (p-value 0.328) or their interaction (p-value 0.177) with the “high consumer” status. The only variable associated with this status turned out to be the age group of the child. Taking the 6-8 yearold age group as reference, the Odds Ratio (OR) of being a “high consumer” was 0.45 (95% C.I. 0.23-0.89) for older children in the age group 9-11 years.

    TABLE 5. Characterization of the High Consumers according to the main study variables. Values for the categorical variables are expressed as a percentage (absolute numbers in parenthesis) and those for the continuous variables as the median (I quartile / median / III quartile).
    TABLE 5. Characterization of the High Consumers according to the main study variables. Values for the categorical variables are expressed
as a percentage (absolute numbers in parenthesis) and those for the continuous variables as the median (I quartile / median / III quartile).
    TABLE 5. Characterization of the High Consumers according to the main study variables. Values for the categorical variables are expressed as a percentage (absolute numbers in parenthesis) and those for the continuous variables as the median (I quartile / median / III quartile). (Cont.)
    TABLE 5. Characterization of the High Consumers according to the main study variables. Values for the categorical variables are expressed as a percentage (absolute numbers in parenthesis) and those for the continuous variables as the median (I quartile / median / III quartile). (Cont.)

    Discusión

    This study was conducted among a sample of Italian children, where TV advertising it is demonstrated to be similar to those in other countries and in particularly in US. A study published in 2010 (21), comparing food advertising in children’s TV channels of Europe, America, Australia and Asia, demonstrated that food is one of the most advertised products in all the countries involved in the study. However, regarding the type of food advertised, it found differences among Italian and US advertising, showing that fast food and chocolate/confectionary are the most common marketed products in US and Italy respectively. These results are consistent with a study (22) conducted on Italian food advertising for children which revealed that sweets were the products most frequently advertised.

    The existence of an association between TV, advertising and risk of being overweight or obese has been evaluated in numerous studies(23-25), obtaining contrasting results. This study aimed at understanding the association between food consumption during snacking times, brand visibility and TV viewing.

    With respect to the primary objective of the study, the assessment of the effect of TV viewing and brand advertising, the present study showed no significant effect on total energy intake. The secondary objective was to evaluate the effect of different levels of brand awareness on children’s intake. Similarly to the previous results, no significant association of increased intake was recorded in any of the two brand awareness groups, showing similar trends also for brand and TV exposure.

    The results of the present study disagreed with previous research studies, where a positive association was found between advertising and TV viewing and increased energy intake. Halford and colleagues showed that 9-11- yearold (26) and 5-7 year-old (27) children increased their intake of most food types after viewing food adverts, and that the ability to correctly recognize these food adverts was significantly associated with higher food intake following food advert exposure. Similar conclusions were found by Lobstein, that in 2004 stated that the overall findings justified the need for taking precautionary measures to reduce children’s exposure to obesogenic marketing practices (11).

    In our study, no significant association between brand visibility and increased caloric intake was found, neither in children with high brandawareness nor in those with low brand-awareness. Children showed a somewhat homogeneous overall intake with a median of 3 snacks per child.

    When considering solely the effect of a brand on children’s snack intake, it resulted that if the packages were unbranded, children (in particular, males) tended to consume a higher number of grams of snacks, therefore increasing their caloric intake. These findings were consistent with those in Anschutz’s research, which highlighted in boys an increased susceptibility to food cues in food commercials (28).

    As suggested also from the research of Francis, TV viewing could either increase or decrease children’s food intakes (25). Specifically, our study showed that in low awareness children, both TV groups experienced a decreased intake of snack when switching from unbranded towards branded packages. Additionally, children not exposed to TV showed an increased intake with branded snacks in comparison with unbranded snacks. Results were nonetheless not significant. Children seemed to be more prone to eat when they weren’t distracted from any other factor, while TV viewing and brand presence didn’t modify their eating behavior towards a larger request of snacks. These findings were not in line with previous ones, which associated increased snacking behavior with screen time (29).

    A multivariable model was used to assess the association between increased caloric intake and other parameters recorded with children questionnaires. In the present sample, confectionery’s habitual consumption appeared to be a protective factor, showing a decreasing effect on overall caloric intake, while being a male and belonging to an older group showed a boosting effect on energy intake.

    As a study limitation, it must be taken into consideration that this body of evidence emerges from an experimental study whose results can be extrapolated in the real life with caution. Nevertheless, all efforts were made to minimize biases. All the participating children attended the same school, attending the same meal supply chain and were brought in to the experimental area by their parents, not having eaten any other item before the study. In addition, the ad libitum method allowed us to focus our attention on the children’s satiety point, giving them complete freedom while they were eating the chosen snacks, without any intervention of the interviewer in terms of neither limiting their choices nor highlighting the presence of the brand on the children’s trays. Finally, we did not investigate children’s preferences towards the snacks presented in the study and consequently we could not evaluate the effect of children’s attitudes on energy intake.

    Implications for Research and Practice

    The present study failed to prove, in an afternoon snacking occasion, an effect of TV viewing and advertising in children, even when considering the high brand awareness subgroup. While breakfast habits and their effects have been largely investigated, the role of afternoon snacking has been less studied, both from nutritional and from behavioral point of view. However, it’s crucial to widely study this snacking occasion in children, because afternoon snack presents unique characteristics that differentiate it from morning snack, especially in Italian context. While in the morning children have snack at school (which could also provide snacks, such as fruits or yogurt, as in some Italian school facilities implementing project for healthy nutrition), in the afternoon children have snacks usually outside school so they could be exposed to TV viewing (and consequently to TV spot).

    Our results might indicate that children’s attitudes to food during afternoon snacking is less modified by exposure to known and common factors like television and advertising. Further research is needed in order to guide health policies aimed at fighting childhood obesity epidemic.

    Source of funding

    The work has been partially supported by an unrestricted grant from the Italian Ministry of Foreign Affairs under the programs “Programmi di alta rilevanza scientifica e tecnologica” Italia-Messico and Italia-Argentina, and from Prochild ONLUS (Italy).

    Acknowledgements

    The study group gratefully acknowledges Ferrero Inc. and Barilla S.p.A. for having provided all the experimental food. All authors declare to not have any conflict of interest.

    Conflicts of interest

    The authors have no competing interests

    References

    1. Bray GA. Obesity: historical development of scientific and cultural ideas. Int J Obes. 1990 Nov;14(11):909-26. PubMed PMID: 2276853. Epub 1990/11/01. eng.
    2. Nadeau KJ, Maahs DM, Daniels SR, Eckel RH. Childhood obesity and cardiovascular disease: links and prevention strategies. Nat Rev Cardiol. 2011 Jun 14. PubMed PMID: 21670745. Epub 2011/06/15. Eng.
    3. LaRosa C, Meyers K. Epidemiology of hypertension in children and adolescents. J Med Liban. 2010 Jul-Sep;58(3):132-6. PubMed PMID: 21462840. Epub 2011/04/06. eng.
    4. Spruijt-Metz D. Etiology, Treatment and Prevention of Obesity in Childhood and Adolescence: A Decade in Review. J Res Adolesc. Mar;21(1):129-52. PubMed PMID: 21625328. Epub 2011/06/01. Eng.
    5. Monasta L, Batty GD, Cattaneo A, Lutje V, Ronfani L, Van Lenthe FJ, et al. Early-life determinants of overweight and obesity: a review of systematic reviews. Obesity reviews : an official journal of the International Association for the Study of Obesity. 2010 Oct;11(10):695-708. PubMed PMID: 20331509.
    6. Caroli M., Argentieri L., Cardone M., Masi A. Role of television in childhood obesity prevention. International Journal of Obesity. 2004;28:104-8.
    7. Mcginnis J.M., Gootman J., Kraak V.I. National Academy of Sciences, Committee on Food Marketing and the Diets of Children and Youth. Food Marketing to Children and Youth: Threat or Opportunity? Press NA, editor. Washington, DC: Institute of Medicine; 2006.
    8. Boyland EJ, Halford JC. Television advertising and branding. Effects on eating behaviour and food preferences in children. Appetite. 2013 Mar;62:236-41. PubMed PMID: 22421053.
    9. Stroebele N., de Castro J. M. Television viewing is associated with an increase in meal frequency in humans. Appetite. 2004;42:111-3.
    10. Jeffery R.W., French S.A. Epidemic obesity in the United States: Are fast foods and television viewing contributing? American Journal of Public Health. 1998;88:227-80.
    11. Lobstein T, Dibb S. Evidence of a possible link between obesogenic food advertising and child overweight. Obesity reviews : an official journal of the International Association for the Study of Obesity. 2005 Aug;6(3):203-8. PubMed PMID: 16045635.
    12. Epstein LH, Roemmich JN, Robinson JL, Paluch RA, Winiewicz DD, Fuerch JH, et al. A randomized trial of the effects of reducing television viewing and computer use on body mass index in young children. Arch Pediatr Adolesc Med. 2008 Mar;162(3):239-45. ed PMID: 18316661. Epub 2008/03/05. eng.
    13. Costa SM, Horta PM, dos Santos LC. Food advertising and television exposure: influence on eating behavior and nutritional status of children and adolescents. Archivos latinoamericanos de nutricion. 2012 Mar;62(1):53-9. PubMed PMID: 23477208.
    14. Ashton D. Food advertising and childhood obesity. Journal of the Royal Society of Medicine. 2004 Feb;97(2):51-2. PubMed PMID: 14749396. Pubmed Central PMCID: 1079287.
    15. Roininen K, Tuorila H, Zandstra EH, de Graaf C, Vehkalahti K, Stubenitsky K, et al. Differences in health and taste attitudes and reported behaviour among Finnish, Dutch and British consumers: a crossnational validation of the Health and Taste Attitude Scales (HTAS). Appetite. 2001 Aug;37(1):33-45. PubMed PMID: 11562156.
    16. Franchin L, Zobec F, Ghidina M, Stefanini G, Berchialla P, Gregori D. Measuring Brand Awareness in as a Component of Eating Habits in Children: the Development of the IBAI (Italian Brand Awareness Instrument). Progress in Nutrition. 2012;14(2):10.
    17. APA. American Psychological Association ethical principles of psychologists and code of conduct 2002 [Retrieved February 9, 2009]. Available from: http://www.apa.org/ethics/code2002.html
    18. Zeger SL, Liang KY, Albert PS. Models for longitudinal data: a generalized estimating equation approach. Biometrics. 1988;44:1049-66.
    19. Zeger SL, Liang KY. An overview of method for the analysis of longitudinal data. 1992;11:1825-39.
    20. R Development Core Team. R: A language and environment for statistical computing. 2008.
    21. Kelly B, Halford JC, Boyland EJ, Chapman K, Bautista-Castaño I, Berg C, et al. Television food advertising to children: a global perspective. American Journal of Public Health. 2010;100(9):1730-6.
    22. Pellai A, Vetrano S, Nobile M, Luti C. The reverse pyramid: a quali-quantitative study about food advertising inside children’s television programmes. Minerva pediatrica. 2012;64(1):15-26.
    23. Miller SA, Taveras EM, Rifas-Shiman SL, Gillman MW. Association between television viewing and poor diet quality in young children. Int J Pediatr Obes. 2008;3(3):168-76. PubMed PMID: 19086298. Epub 2008/12/17. eng.
    24. Hare-Bruun H, Nielsen BM, Kristensen PL, Moller NC, Togo P, Heitmann BL. Television viewing, food preferences, and food habits among children: A prospective epidemiological study. BMC Public Health. 2011;11:311. PubMed PMID: 21569476. Epub 2011/05/17. eng.
    25. Francis LA, Birch LL. Does eating during television viewing affect preschool children’s intake? Journal of the American Dietetic Association. 2006 Apr;106(4):598-600. PubMed PMID: 16567158. Pubmed Central PMCID: 2596580. Epub 2006/03/29. eng.
    26. Halford JC, Gillespie J, Brown V, Pontin EE, Dovey TM. Effect of television advertisements for foods on food consumption in children. Appetite. 2004 Apr;42(2):221-5. PubMed PMID: 15010186.
    27. Halford JC, Boyland EJ, Hughes G, Oliveira LP, Dovey TM. Beyond-brand effect of television (TV) food advertisements/commercials on caloric intake and food choice of 5-7-year-old children. Appetite. 2007 Jul;49(1):263-7. PubMed PMID: 17258351. Epub 2007/01/30. eng.
    28. Anschutz DJ, Engels RC, Van Strien T. Side effects of television food commercials on concurrent nonadvertised sweet snack food intakes in young children. The American journal of clinical nutrition. 2009 May;89(5):1328-33. PubMed PMID: 19321557.
    29. Ford C, Ward D, White M. Television viewing associated with adverse dietary outcomes in children ages 2-6. Obesity reviews: an official journal of the International Association for the Study of Obesity. 2012 Dec;13(12):1139-47. PubMed PMID: 22958789.