(Medical Xpress)—Physical activity rather than food has the biggest impact on children's weight according to new data from the Lifestyle of our Kids (LOOK) longitudinal study.
Lead researcher Professor Richard Telford from the ANU College of Medicine, Biology and Environment and the Clinical Trials Unit at The Canberra Hospital said the new aspect of the LOOK study provides some of the strongest evidence to date in the important debate around how best to tackle childhood obesity.
"Our four-year study of 734 otherwise healthy Australian children in the general community, aged between 8 and 12 years, found that the main difference between lean and overweight children was that lean children were more physically active," Professor Telford said.
"Children with a higher proportion of body fat, even those considered obese, did not consume more kilojoules - they did not eat more fat, carbohydrate or sugar - than those who were lean.
"Indeed, our study found that leaner boys actually consumed more kilojoules over the four years of the study than overweight boys, but were much more physically active.
"The data also indicated that if a child became more active during the four years he or she became leaner. Alternatively, a child who became less active increased his or her body fat percent."
During the study, physical activity was measured objectively with pedometers and accelerometers. Body fat was measured using body fat dual emission x-ray absorptiometry, and dietary intake was measured by nutritionists using the methods employed by the CSIRO in national surveys.
Professor Telford said a number of strategies were adopted to reduce the likelihood of misreporting food intake, including interviews with children and parents, as well as written records of daily intake and careful measurement of quantities, which added to the researchers' confidence in their findings.
He said the strength of the findings also suggested the time had come to revisit how weight issues in young children are best addressed.
"General community strategies involving dietary intake and physical activity to combat childhood obesity may benefit by making physical activity the foremost focus of attention," Professor Telford said.
LOOK researchers conducted this aspect of the study between 2005 and 2010. The results have been published in PLOS ONE today.