A survey of 18,486 secondary school students at 322 schools across all Australian states except Western Australia has found that a significant proportion of students fall short of current, national dietary and physical activity recommendations for teenagers.
Published in the September issue of Health Promotion International*, the survey findings indicate that secondary school students between the ages of 12 and 17 are consuming far too much junk food and not enough vegetables and fruit.
Study author Dr Victoria White, from the Centre for Behavioural Research in Cancer at The Cancer Council Victoria, said the survey found that only 20% of students were meeting the daily requirement of four serves of vegetables while 39% were eating the recommended three daily serves of fruit.
"Our survey found consumption of unhealthy/non-core foods was high, with 46% of students having fast food meals at least twice a week, 51% eating snack foods four or more times per week, and 44% having high-energy drinks four or more times per week.
"Students' dietary behaviour was found to be related to their television viewing habits, with heavier television use associated with lower consumption of fruit and higher consumption of unhealthy foods of low nutritional value," she said.
The survey findings also highlight the need for secondary students to spend more time being physically active and less time in front of the television and computer.
"We found that only 14% of students engaged in recommended levels of physical activity and about 70% exceeded recommended levels of sedentary behaviour," she said. Current recommendations** state teenagers should do at least 60 minutes of moderate- to vigorous-intensity physical activity every day and spend no more than 2 hours per day using electronic media for entertainment.
The Cancer Council Australia is calling on the next Australian Government to build on the COAG Australian Better Health Initiative with a more coherent national strategy to reduce obesity, supported by food marketing policy reform.
The Cancer Council Australia's Chief Executive Officer, Professor Ian Olver, said the survey was an important new piece of evidence showing why obesity levels in Australia more than doubled between the mid-1980s and the mid-'90s.
"Obesity and overweight are important causes of cancer and, unless current trends in child and adolescent obesity are turned around, will have an unprecedented impact on future cancer incidence and mortality in Australia," Professor Olver said.
"With up to three quarters of obese children and adolescents becoming obese adults, we may be looking at the genesis of a major increase in the already prevalent cancers linked to obesity and overweight, such as bowel cancer and breast cancer in postmenopausal women."
Professor Olver said the COAG Australian Better Health Initiative had laid the platform for a whole-of-government approach to addressing obesity, but it needed a more coherent national strategy incorporating social marketing, research and, in particular, policy reform.
"Government-backed measures to better research the problem of obesity and encourage healthier eating and more physical activity are likely to be far more effective if they are not competing with multimillion dollar advertising campaigns promoting unhealthy food," he said.
"The results of this survey, combined with the growing evidence that food marketing reform is the most cost-effective intervention to reduce childhood and adolescent obesity, emphasise the need for government to restrict junk food advertising as part of a comprehensive approach to reducing tomorrow's cancer burden through improved nutrition and physical activity in today's 12 to 17 year olds."
*Dietary, physical activity and sedentary behaviour among Australian secondary students in 2005. (Maree Scully, Helen Dixon, Victoria White and Kerri Beckmann).
** Department of Health and Ageing, 2004.
Note to editors:
The aim of this study was to provide a current assessment of Australian secondary students' self-reported dietary, physical activity and sedentary behaviour. This study also examined the relationship between television viewing and students' dietary behaviour. Data are from a cross-sectional survey of 18,486 secondary students in 2005 from all Australian states except Western Australia. Participants reported their usual daily consumption (number of serves) of vegetables and fruit; their weekly consumption of unhealthy/non-core foods including fast food meals, snack foods and high-energy drinks; their engagement in moderate-vigorous physical activity over the previous week; and hours spent using electronic media for entertainment and doing homework on school days. The study found that 20% of students were meeting the daily requirement of four serves of vegetables whereas 39% were eating the recommended three daily serves of fruit. Consumption of unhealthy/non-core foods was high, with 46% of students having fast food meals at least twice a week, 51% eating snack foods four or more times per week, and 44% having high-energy drinks four or more times per week. Fourteen percent of students engaged in recommended levels of physical activity and 29% engaged in recommended levels of sedentary behaviour. Age and gender differences occurred for most measures, and there were some socio-economic status differences. Heavier television use was associated with lower consumption of fruit and higher consumption of unhealthy/non-core foods. On the basis of the results of this study, it appears that a significant proportion of Australian secondary students fall short of current, national dietary and physical activity recommendations for teenagers. Continual monitoring of these behaviours is essential to help inform research and policy and identify where future efforts should be directed.
(Health Promotion International, 22(3): 236-245, September 2007)