Investigation into the sustained impact of food advertising on children’s dietary intake and its potential to influence children’s weight

Brief summary: The aim of this research was to investigate the direct effects of children’s exposure to food advertising on their dietary intake and its potential influence in the development of childhood overweight. Across a series of six-day holiday camps, children (n=160, aged 7-12 years) were exposed to food and non-food advertising in an online game and/or a television cartoon in a randomised within-subject, cross-over, counterbalanced design. The primary aim of the study is to explore whether short-term increases in snack intake following food advertising exposure are compensated for at a subsequent lunchtime meal; and hence identify if food advertising contributes to a positive energy balance likely to contribute to childhood overweight. Brief background: There is a recognised link between unhealthy food marketing and childhood obesity yet major regulatory reform remains essentially unimplemented. Children continue to be exposed to high levels of unhealthy food marketing across a wide range of media and settings. A key reason for the failure to restrict marketing to children has been the shortage of evidence showing a direct link between food marketing and children’s weight. The aspect of food marketing that will be the focus of this study is food promotion, specifically television advertising and online advertising (in the form of branded games (‘advergames’) ) and their potential impact on children’s food consumption. Short term experimental studies, designed to assess the effect of unhealthy food advertising (embedded in either a cartoon or in a game) and children’s subsequent food intake, show there is an immediate direct effect from single exposure (children consume more snack foods). This study aims to observe what happens to children when they are exposed to food advertising over a longer period; to investigate the effect of food advertising across multiple media; and to explore the potential impact of exposure on longer term dietary intake. Setting: We partnered with the University of Wollongong (UOW) School Holiday Sports Camp and UOW’s Early Start to conduct this study. Early Start is a child-focused research facility on the same campus as the holiday camp. The study was conducted as part of usual care at the UOW holiday camp during the morning session (8am-1.30pm). Camps run during each school holiday period, four times a year. Morning session camp fees for children participating in the study were fully funded. The interventions were conducted in rooms within Early Start. A pilot study was run during the school holiday period in January 2016, followed by the main four studies which were run during the school holidays in April, July and September 2016 and January 2017, each for a period of six days. Study population: Children aged 7-12 years (n=160 (n=40 x 4 camps)) Study design: The study utilised a within–subject, randomised, crossover, counterbalanced design with two media condition arms: multiple media (TV plus advergame) or single media (TV only). Each media arm had two advertising conditions: control (an advergame featuring a non–food brand and/or exposure to ten non–food TV advertisements) and experimental (an advergame featuring a food brand and/or exposure to ten TV food advertisements). Two groups of 20 children were formed for each camp, with an approximate even spread of gender and age between groups. The two groups were then randomised to one of the two media arms (single or multiple media). Within each holiday camp children remained within the media arm to which they were allocated, and completed both the food advertising and non-food advertising conditions within their allocated media group. Each advertising condition lasted for three days with the order of advertising exposure counterbalanced across holiday camps. The food advertising condition was first in the April and September camps and second in the July and January camps. The April, September and January camps had a washout period of four days between Days 1-3 and Days 4-6. There was no washout period during the July camp: this was constrained due to the camp organisers only running the children’s holiday camp over a six day period. Materials: The TV advertisements (approximately 30 seconds each) were embedded within a ten minute age–appropriate, gender–neutral cartoon and shown each day. The cartoons were matched by series across condition but with a different episode of the cartoon shown each day. There were no references to, or depictions of, foods or eating in any of the cartoons screened. In order to isolate the effects of the study advertising exposure, the branded products selected for the experimental condition were for real products available in other countries but not available for sale in Australian supermarkets or advertised on commercial TV within Australia. Daily procedure: Each morning at 8am, children arrived fasting (self-reported by parents/caregivers) at the Early Start research centre and signed in by their parents/caregivers, who then left. Children washed their hands and were then served breakfast. The dining space was set up with 40 individual trays and, each day, children were offered a selection of portioned breakfast cereals, fruit, toast or pikelets, spreads and water to drink. Four research assistants supervised the children. The children were told that they could eat as much or as little as they liked, and were given more of each food item as requested. Children were allocated a unique identifying number which was placed on their meal tray at each eating occasion and used to track how much each child ate daily. After 30 minutes, the children left to participate in the nearby holiday camp activities. Camp leaders ensured that the physical intensity of camp activities was similar each session and day of the sports camp. Children’s breakfast intake was quantified by assessing whether children had eaten all, more than half, half, less than half or none of each food item. Kilojoules (kJ) were estimated from the proportion of each standardised food item consumed, and children’s mean breakfast intakes for the three days of food and three days of non–food advertising were estimated. At mid–morning children were directed to their intervention rooms in the research centre with each room supervised by two trained research assistants. All children washed their hands and a roll call was taken. The rooms were bright and colourful with a carpeted floor and a large, wall mounted TV screen. Children in both intervention rooms were asked to take a seat on the floor and to report how hungry they felt by filling out a picture rating scale. Children were then told that they would be watching a cartoon and some advertisements. Once the cartoon had finished, iPads were distributed to the children in the multiple media condition and, after an explanation on how to play, they played an advergame for 5 minutes. In both rooms, after media exposure was complete, individual trays with six small bowls of snack foods were given out. Bowls contained 50 grams of each of the following foods: high fat savoury (crinkle–cut crisps, plain potato crisps or chicken–flavoured crackers); low fat savoury (pretzels, plain crackers or rice crackers); high fat sweet (milk chocolate, chocolate–covered biscuits or sugar–coated chocolate confectionery); low fat sweet (assorted jelly lollies); fruit (green and black grapes or peeled mandarin segments); and vegetable (carrot sticks). These selections were in line with previous study designs. Snack items offered on Day One were matched with those offered on Day Four, Day Two with Day Five and Day Three with Day Six. None of the brands offered to children to eat were featured in any of the advertisements. Children were asked to wait until everyone had their trays before they could start eating. They were, again, told that they could eat as little or as much as they liked, and if they would like some more they should put their hand up and they would be given more of the requested food. This was the only time either food or eating was referred to by the research assistants. Advertisements were not discussed with the children. Eating time was limited to 15 minutes after which children were instructed to stand up and leave the room. Afterwards children left to take part in further holiday camp activities and the remaining food on each child’s tray was weighed and recorded. Lunch was served at 13.00 each day back in the research centre dining room. Once again 40 individual trays were set up with pre–weighed food items. There was a different menu for Days One to Three which was repeated on Days Four to Six. Lunch items included fruit, vegetables, yoghurt and healthier versions of fast food, e.g. low fat beef burger, oven baked chicken pieces and chips. The dining room was supervised by a minimum of 4 research assistants. All children washed their hands before eating. Each day prior to lunch, children completed the picture rating scale to report how hungry they felt. As with the previous meal occasions, children were told that they could eat as little or as much as they liked and if they would like some more to ask and they would be given more of the requested food. Parents arrived to pick children up at 13.30, whereupon children were signed out. Once children had left, all remaining individual food items were weighed and recorded. We did not collect dietary data from children once they left camp for the day. Parents and children completed online questionnaires at baseline (prior to study commencement) and 1 week post study completion. Parent questionnaires included child and family baseline characteristics (including Birch et al's (2001) validated Child Feeding Questionnaire). Other questionnaire content is detailed in the "Outcomes" section.