As thousands of Aussie kids start summer holidays this week, there's no doubt parents will see an increase in kids' screen time, snack time and general relaxation. After a busy school year, it's well-deserved, but could this change in activity have an adverse impact on their health?
In a new University of South Australia study, researchers are examining changes in children's diets and time use over the summer holidays, in a move to better understand factors that are affecting childhood obesity.
Childhood obesity is one of the most serious public health challenges of the 21st century, with more than 340 million children affected globally. In Australia, one in four children are overweight or obese.
UniSA's Professor Tim Olds says it's imperative to understand contributors to childhood obesity.
We haven't seen any reduction in childhood overweight and obesity, despite hundreds of studies and tens of millions of dollars.
What we know about overweight and obese children is that they are more likely to stay this way into adulthood, making them more likely to be at risk of diabetes and cardiovascular diseases at a younger age.
Strong evidence in the US and Europe shows that the entire increase in children's fatness - and decrease in fitness - occurs during the summer holidays, but in Australia, we don't yet have this data.
We do know, however, that Australian kids use their time very differently on holidays which, when coupled with diet, may be associated with increased weight gain and reduced fitness.
Each day on holidays kids get almost an hour's more screen time, 40 minutes' more sleep, and about 15 minutes less physical activity compared to term time.
This study will be the first in Australia to examine both children's eating habits and their use of time over the summer holidays, so that we can find effective ways to address the very serious issue of childhood obesity."
Tim Olds, UniSA Professor
Funded by the National Health and Medical Research Council (NHMRC), the longitudinal study will track the 24-hour behaviour of more than 300 Grade four students (aged approximately nine years) over three years, assessing diet, time use, and activity, as well as fitness and body-fat percentages.
Prof Olds says that the unstructured nature of holidays could be associated with poorer diets, lower physical activity and more screen time, and hence increased fatness and reduced fitness.
"Clearly, when kids are at school, their time is highly-structured - they have set times for PE (physical education) and opportunities to exercise - plus, and their calorie intake is mostly limited to what they have in their lunchbox," Prof Olds says.
"On holidays, the days are much more unstructured, with a lot of free time to watch TV, play video games and raid the pantry - all sedentary behaviours that can increase the risk of weight gain and reduced fitness.
"If we can find links between children's fitness and fatness on summer holidays, we can start to think differently about interventions such as structured holiday programs and camps, as well as family-based interventions, that can boost children's physical activity over summer.
"Being overweight or obese is largely preventable and putting the break it for our kids is a priority for parents, schools and policy."
Watson, A., et al. (2019) Life on holidays: study protocol for a 3-year longitudinal study tracking changes in children’s fitness and fatness during the in-school versus summer holiday period. BMC Public Health. doi.org/10.1186/s12889-019-7671-7.