Cultural Background The FSANZ phone survey of adolescents and young adults in Australia found that Aboriginal and Torres Strait Islanders were more likely to consume sugar-sweetened soft drinks compared to other Australians (72 per cent versus 50 per cent) and consumed significantly larger amounts (249 ml versus 128 ml per day) (Food Standards Australia New Zealand 2003a). The 2004 SPANS survey of children in Years 6–10 in NSW found consumption of soft drinks to be lowest among students of Asian background and highest among boys of Southern European and Middle Eastern background (Booth et al. 006). Gender Fewer girls than boys consume soft drink in Australia, and among those that do, girls consume smaller amounts of soft drink than boys (section 2. 2). This gender effect has been observed in Europe also. For example, the large WHO collaborative cross-national study of Health Behaviours among School-aged Children 2001–02 showed that girls generally consume less soft drink than boys (Vereecken et al. 2005b). Psycho-Social Factors 3. 2. 1 Personal Factors Personal factors appear to moderate the relationship between environmental factors and behaviour.
In Norway, personal preferences, i. e. taste, was the number one determinant of soft drink consumption, and attitude was the fourth most important determinant of soft drink consumption in adolescents, with the environmental factors of accessibility and modelling (consumption behaviour of significant others) in between (Bere et al. 2007). Soft drink consumption in school-aged children has been notably correlated with taste preferences in other studies (Grimm et al. 2004). In one study of 8–13 year olds in the US, those who reported the strongest taste preference were 4. times more likely to consume soft drinks five or more times per week compared with those with a lower taste preference. A focus group study with groups of children aged 8–9 years and 13–14 years showed that younger children prefer the taste of still, fruit-flavoured drinks and adolescents prefer the taste of carbonated drinks (May and Waterhouse 2003). Attitude and subjective norm (perception of other people’s views and attitudes towards soft drink consumption), together with perceived behavioural control, explained 60 per cent of the variance in intention to drink regular oft drinks in 13–18 year olds in the US (Kassem et al. 2003; Kassem and Lee 2004). However, taste enjoyment was one of the most predictive expected outcome beliefs of regular soft drink consumption. In quenching of thirst was the second most important predictor of attitude, after taste, towards drinking soft drinks — yet soft drinks have been found to be poor at quenching thirst when compared to water (Rolls et al. 1990; Brouns et al. 1998).
Parents and friends have been identified as being more influential than peers in the consumption patterns of younger children aged 8–9 years in the UK (May and Waterhouse 2003), although peer groups are considered to play a greater role in adolescence (Buchanan and Coulson 2006). Cost, availability and thirst were more important in older children aged 13–4 years. In the NSW Schools Physical Activity and Nutrition Survey 2004 (SPANS) of children aged 5–16 years, peer influences were not particularly apparent in soft drinks attitudes and intended consumption (Booth et al. 006). Adolescents who perceived more social pressure to limit soft drink consumption were found to be more likely to consume more in the Study on Medical Information and Lifestyle in Eindhoven (SMILE) study in The Netherlands (de Bruijn et al. 2007). The SMILE study also showed that moderate “agreeableness” (a measure of adolescents” willingness to comply with parental practices and rules) of adolescents is associated with less soft drink consumption, however, those that were most “agreeable” consumed a lot (de Bruijn et al. 2007).
This was attributed to pressures outside of the home environment — pro-social motives where those most agreeable wanted to “fit in”. It is postulated that the more agreeable adolescents were more inclined to live up to expectations raised by prototype-based advertisements and marketing. One of the few studies examining the factors affecting soft drink consumption in adults showed that consumption of sugar-sweetened soft drinks was associated with less restrained and more external eating, i. e. sensitive to external stimuli such as taste (Elfhag et al. 2007).
The study, conducted among 3265 adults in Sweden showed that, in contrast, diet soft drinks were consumed by persons with a higher body mass index (BMI) (possibly in an attempt to reduce their weight), more restrained eating and more emotional eating. Parents as Models A study in Australia showed that the influence of mothers, either as models of eating behaviours or as the providers of food, is pervasive (Campbell et al. 2007). Parental soft drink consumption was positively associated with younger children’s intake in two studies (Grimm et al. 2004; Vereecken et al. 004). Mother’s consumption was found to be an independent predictor for regular soft drink consumption among children in Belgium (Vereecken et al. 2004). In the US, children aged 8–13 years whose parents regularly drank soft drinks were nearly three times more likely to consume soft drinks five or more times per week compared with those whose parents did not regularly drink soft drinks (Grimm et al. 2004). A higher frequency of preparing food was found to be related to lower intakes of carbonated beverages among female adolescents in the US (Larson et al. 006). Parenting Styles Less restrictive parenting practices are associated with a higher consumption of healthier food options such as fruit and vegetables in children; however the evidence is not as equivocal for soft drinks. Indeed, the converse has been found in some recent studies. For example, van der Horst et al found that in The Netherlands less restrictive parenting practices, relating to specific behaviours such as “food rules”, were associated with higher consumption of sugar-sweetened beverages among 383 adolescents (van der Horst et al. 2007).
This association was independent of perceived parenting practices by the adolescents, and was mediated by attitude, self-efficacy and modelling from parents (parental consumption). The association was strongest among adolescents who perceived their parents as being moderately strict and highly involved. These authors concluded that parents should be involved in interventions aimed at changing dietary behaviours including soft drink consumption and that interventions aimed at the promotion of healthy parenting practices are best tailored to the general parenting style of the participants (for example, strict and/or involved).
More restrictive parenting practices were also found to be associated with less soft drink consumption (De Bourdeaudhuij and Van Oost 2000) and stricter parenting practices were found to be associated with less soft drink consumption in a recent study in The Netherlands (de Bruijn et al. 2007). However, findings from studies among younger children suggest that strict parental practices can in fact increase children’s preferences for, and intake of, the restricted foods. These different findings may relate to differences in the ype of practices used between age groups. For example, parents of younger children might use pressure to get their children to eat more or may restrict access to certain foods. For adolescents, parents might use clearly defined rules about the times when a certain food can be eaten and how much of a certain food they can eat. Environmental Factors 3. 3. 1 Soft Drink Availability Availability at School Increased soft drink consumption has been related to the availability of soft drinks in vending machines in the school environment in a number of studies.
However, it appears that when soft drinks are ubiquitous in schools the link between consumption and availability is less discernible (French et al. 2003; Grimm et al. 2004; Vereecken et al. 2005a). Access to vending machines selling soft drinks in schools in the US was not related to consumption in either boys or girls (Kassem et al. 2003; Kassem and Lee 2004). In Norway, most soft drink consumption occurs outside of school despite soft drinks currently still being available in schools (Bere et al. 007). Vending machines were not available in schools involved in a study of adolescent soft drink consumption in the UK (Buchanan and Coulson 2006); and this study found that consumption of soft drinks was higher at the weekends. Nevertheless, the availability of soft drinks at school, either in the school canteen or in vending machines, may send messages to children that they are suitable drinks; also their easy availability at schools negates the need to provide water.
The sale of foods and drinks at schools is likely to have a ripple effect in the community (Bell and Swinburn 2005), thus banning soft drinks at schools conveys a healthy message to children and this message has the potential to affect community attitudes. In recent years four Australian state governments (New South Wales, Victoria, South Australia and Western Australia) have accordingly imposed a ban on the sale of soft drinks and other sugar-sweetened drinks by canteens in public schools (Bell and Swinburn 2005). In NSW this ban on sugar-sweetened drinks is part of Fresh Tastes @ School, the NSW Healthy School Canteen Strategy.
Sugar-sweetened drinks with more than 300 kJ per serve or more than 100 mg of sodium per serve have not been allowed in school canteens and vending machines in NSW since Term 1, 2007 (NSW Department of Health and NSW Department of Education & Training 2006). These drinks include: soft drinks, energy drinks, fruit drinks, flavoured mineral waters, sports drinks, cordials, iced teas, sweetened waters, sports waters, and flavoured crushed ice drinks. In Victoria the ban extends to high-energy, high-sugar soft drinks brought in to school. Portion Size
The beverage industry has steadily increased container sizes over the last 50 years. In the 1950s the standard serving size was a 200 ml bottle, which increased to a 375 ml can, which was superseded by a 600 ml bottle. Studies have shown that the larger the container, the more people are likely to drink, especially when they assume they are buying single-serve size containers. For example, Flood et al have shown that increasing beverage portion size from 350 ml to 530 ml significantly increased the weight of beverage consumed regardless of beverage type — in this case regular cola, diet cola or water (Flood et al. 006). As a consequence, energy intake increased 10 per cent for women and 26 per cent for men when there was a 50 per cent increase in the portion of regular cola served. Food intake did not differ under the controlled conditions; thus overall energy intake was increased as a result of the extra energy from the larger beverage intake. Most recently, a study showed that increasing portion sizes of all foods and beverages consumed by study participants by 50 per cent of baseline increased energy intake from all food and beverage categories, except fruit as a snack and vegetables, for an 11-day period (Rolls et al. 007). The amount of beverage consumed increased from about 470 ml in both women and men to 557 ml in women and 630 ml in men. Disproportionate pricing practices also encourage people to drink large servings as these often cost just a fraction more than the smaller servings (Young and Nestle 2002). Large serve sizes contribute to an “obesogenic” environment, as they facilitate excess consumption of energy (Dietary Guidelines Advisory Committee 2005). Dietary guidelines and public campaigns have highlighted the importance of portion size as a central concept related to energy intake (Matthiessen et al. 003). Cost In a number of papers, Drewnoswki and co-workers purport that the main issue in relation to nutrient-poor foods and beverages and obesity is the cost; that is, nutrient-dense diets are more costly than nutrient-poor, energy-dense foods which are relatively cheap. Drewnowski and Bellisle (2007) conclude that the obesity-promoting capacity of different beverages is linked not so much by their sugar content but by their low price, although these researchers concur that taste is likely to be the main factor affecting the obesity-promoting capacity of soft drinks (Refer to Section 3. ). Cost was reported as being an important determinant of carbonated soft drink consumption, as opposed to fruit juice and still fruit drinks, in children aged 13–14 years in a study in the UK (Buchanan and Coulson 2006). Availability and thirst were also recognised as important determinants, although foremost was taste. Exposure to TV advertising Television is a medium through which children are commonly exposed to food marketing. Food marketers advertise heavily during children’s programming in Australia (Hastings et al. 007; Kelly et al. 2007), and soft drink is consistently featured near the top of the list of advertised food items in different countries, including Australia (Kotz and Story 1994; Lemos 2004). Increased soft drink consumption has been related to TV exposure in a number of studies (Grimm et al. 2004; van den Bulck and van Mierlo 2004; Utter et al. 2006). The relationship was observed for adolescent boys only — not girls — in a recent study of children in grades 7–8 in Belgium (Haerens et al. 2007).
A study of children aged 5–6 years and 10–12 years in Melbourne showed that children who watched TV for more than 2 hours per day were 2. 3 times more likely to consume ? 1 serve/day of high-energy drinks than children who watched less than or equal to 2 hours of TV per day (Salmon et al. 2006). Functional Drinks 5. 4. 1 Sports Drinks Sports drinks were designed to aid sport performance as well as provide rehydration after sporting events. They contain 6–8 per cent carbohydrates, usually in the form of sugar, plus other electrolytes (Sports Dietitians Australia 2007).
As the name implies, sport drinks are designed for sports participants. Using sport drinks for normal hydration purposes is not recommended because of their energy content (one 600 ml bottle of sport drinks provides around 780 kJ) and their acidity which is associated with the same dental health problems as soft drinks. In Australia sports drinks currently account for less than 5 per cent of the more than 1. 3 billion litres of non-alcoholic beverages sold per annum, but the sale of sports drinks is growing faster than most other beverages (Australian Convenience Store News 2006). Energy Drinks
In recent years, energy drinks have also been introduced as alternative premium products to ordinary soft drinks. Their sales have risen quickly and it has been reported that in the United States energy drinks outperformed all other beverage categories, with more than 500 per cent growth in sales from 2001–06 (Montalvo 2007). The Australian Convenience Store News (Nov/Dec 2006) indicates that energy drinks accounted for 22 per cent of total drink sales. Most consumers were in the 15–39 age bracket and consumption is slightly skewed towards males (Australian Convenience Store News 2006).