The most significant behavioural difference between overweight and non-overweight Canadian boys between age 6 and 17 appears to be the amount of time they spend in front of a television, video or computer screen. However, a new study from the Canadian Institute for Health Information (CIHI) found that this does not apply to teenage girls. Instead, the main difference between overweight and non-overweight girls between age 12 and 17 is the daily consumption of fruit and vegetables.
The study, Comparing Activity and Fruit and Vegetable Consumption by Weight Status Among Children and Youth, is based on survey data from Statistics Canada(1) and compares lifestyle behaviours between overweight and non-overweight children (age 6 to 11) and youth (age 12 to 17). The behaviours examined in the study include screen time activities, fruit and vegetable consumption and physical activity.
"Over the past two decades, the proportion of overweight children and youth has grown tremendously in Canada, by more than 70%," says Lisa Corscadden, Senior Analyst with CIHI's Canadian Population Health Initiative and lead author of the study. "Our study examines how lifestyle behaviours between weight groups differ by age, as well as by sex. This is important to note when tailoring exercise and lifestyle programs for children and youth."
Screen time most significant behavioural difference for grade school children and male youth
CIHI's study found that overweight children between age 6 and 11, regardless of sex, were much more likely to report high levels of screen time than their non-overweight peers. According to the study, 48% of overweight children in this age group reported spending at least two hours a day in front of a television, video or computer screen, compared to 31% of their non-overweight peers. This difference was particularly pronounced among boys age 6 to 11, with more than half (52%) of overweight boys spending more than two hours of their spare time each day in front of a screen, compared to only 32% of their non-overweight peers.
Among male youth between age 12 and 17, the screen time percentages jumped to three out of four (75%) overweight boys spending two hours or more per day in front of a screen versus two out of three (67%) of their non-overweight peers.
"The amount of time spent in front of a television, video or computer screen emerged as the most significant behavioural difference between overweight and non-overweight children and male youth observed in our study," explains Jean Harvey, Director of CIHI's Canadian Population Health Initiative. "This is important for parents and educators to keep in mind as cooler weather sets in and young children spend more time indoors. Screen time, after all, is sedentary time-and our study shows a definite link between a child's weight and so-called 'couch potato' behaviour."
Fruit and vegetable consumption differs between weight groups in female youth
While the level of screen time did not appear to differ between overweight and non-overweight girls age 12 to 17, fruit and vegetable consumption stood out as the main difference observed between weight groups for girls in this age group. Two out of five (40%) non-overweight female youth reported eating fruit and vegetables five times or more a day, compared to slightly more than one in four (27%) overweight girls. No significant difference was seen when comparing fruit and vegetable consumption between weight groups among male youth.
The study also found fruit and vegetable consumption did not differ by weight group among children, with 40% of both overweight and non-overweight boys and girls reporting eating fruit and vegetables five times or more daily. However, the study did not look at differences in other eating habits, such as the consumption of food of low nutritional value.
Sedentary behaviour more closely linked to weight status than reported physical activity
In this study, physical activity did not appear to differ by weight status of any group, with both overweight and non-overweight children and youth reporting very similar levels of daily physical activity. More than 80% of both overweight and non-overweight girls and boys age 6 to 11 had at least one hour or more a day of activity between in-school and extra-curricular activities. For 12-to-17-year-olds, physical activity levels dropped off, with roughly one out of three girls and one out of two boys engaging in physical activity for at least one hour a day-which applied equally for both overweight and non-overweight groups.
"The health benefits of increased physical activity among children and youth are unequivocal, regardless of their association with body weight or weight loss. Increased physical activity and decreased screen time are both effective, health-promoting strategies," says Mark Tremblay, Chief Scientific Officer for Active Healthy Kids Canada and research scientist at the Children's Hospital of Eastern Ontario. "Some studies informed by self-reported data fail to demonstrate significant benefits of physical activity. However, studies using more direct measures of physical activity typically show positive effects and reinforce the wisdom of establishing healthy active living behaviours as early in life as possible."
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