Being overweight makes children less active

A new study from the University of Copenhagen's OPUS Research Centre reports that being overweight makes children less active.

The findings underscore that parents of overweight children have an obligation to keep their children active, as physical activity is vital for the general health of all children.

The study also shows that slender children do not become overweight due to a lack of activity.

Over time, children with a higher fat mass reduce their level of physical activity and increasingly pursue sedentary activities such as watching TV or computer gaming.

Conversely, low levels of physical activity or too much time in front of the TV or computer do not cause normal-weighted children to put on weight.

The findings stem from a large study that has just been published in the esteemed journal, the 'International Journey of Obesity'.

New knowledge about the linkage between physical activity and overweight children

The study presents an entirely new body of knowledge about the links between physical activity and being overweight because it investigates developments among test participants over time.

In contrast, most other studies have measured activity at a single point in time, making it impossible to establish whether activity levels affect being overweight, or whether being overweight influences the level of activity:

"The defining characteristic of our work is that we have left a period of six months in between our measurements of activity and weight."

Mads Fiil Hjorth

"Thus, we have been able to investigate how an overweight child's level of activity develops over a half-year," says Mads Fiil Hjorth, a researcher of physical activity, sleep and obesity at the University of Copenhagen's OPUS Research Centre.

Mads Fiil Hjorth emphasises that physical activity is of great value to children.

"Even though our study, in part, shows that a lack of physical activity and lots of TV and computer do not cause children to gain weight, physical activity is obviously very good for children's general health and welfare in a number of other ways.

We have not focused on these areas in this study. Instead, we have specifically focused on the link between physical activity and fat mass."

Danger not limited to those who are overweight

Anders Sjödin

Associate Professor Anders Sjödin, head of OPUS' research into children's activity patterns, points out that the problem also extends to a segment of normal-weight children:

"It wasn't only those children who are classically understood as being overweight who demonstrated poor development in activity levels."

"There were also normal-weight children with slightly larger fat masses," according to Sjödin.

"So, there is no doubt that if someone has a child with a bit too much to pinch around the midsection, parents need to stay attuned to the child's level of activity."

The Method
The study included 600 third and fourth grade children who were equipped with an activity tracker on two occasions, for seven days at a time.

The activity tracker was worn at the start of the project and again after six months. The tracker was able to register around the clock activity levels.

These measurements were compared with measurements of fat mass at both the beginning and end of the project.

Among other things, this demonstrated that children with the highest fat mass experienced the greatest reduction in the amount of activity over the half-year period.

The study's results can be read in the article, Fatness predicts decreased physical activity and increased sedentary time, but not vice versa: support from a longitudinal study in 8-11 year old children', published in the 'International Journey of Obesity'.

More information: "Fatness predicts decreased physical activity and increased sedentary time, but not vice versa: support from a longitudinal study in 8- to 11-year-old children." M F Hjorth, J-P Chaput, C Ritz, S-M Dalskov, R Andersen, A Astrup, I Tetens, K F Michaelsen and A Sjödin. International Journal of Obesity (5 December 2013) | DOI: 10.1038/ijo.2013.229

Sorry but Parents' diet choice knowledge doesn't prevent Child Obesity

A study of the families of 150 preschoolers suggests that parents of healthy-weight and overweight preschoolers are generally well aware of dietary risk factors that fuel childhood obesity.

The research, conducted by the Johns Hopkins Children's Center and the All Children's Hospital in Florida, suggests that awareness alone is not enough to effect meaningful weight change, and that pediatricians should help parents with specific and tailored guidance on how to apply their knowledge in daily practice, the researchers said.

The study, published ahead of print on April 11 in the journal Clinical Pediatrics, also illuminates the gap between what parents know about the root causes of obesity and what they can actually do to maintain healthy diets for preschoolers, a group generally overlooked in obesity research and prevention.

"When it comes to obesity prevention, the focus tends to be on school-age children and teens, but a growing body of research has found a link between poor life-long health and being overweight as early as 2 years of age," said lead investigator Raquel Hernandez, M.D. M.P.H., a pediatrician at Johns Hopkins.

The Centers for Disease Control and Prevention define children with a body-mass index at or above the 85th percentile for their age as overweight. One-third of the 150 children in the current study were overweight, most from low-income urban homes, and more than 90 percent African-American.

"Childhood obesity is a complex, multi-factorial phenomenon but our findings reveal that, for the most part, lack of parental awareness of nutritional risk factors is not one of the drivers behind it," Hernandez said.

The investigators set out to identify parental perceptions of risk factors for childhood obesity and barriers to healthy weight and to determine whether the parents of healthy-weight preschoolers viewed such risks and barriers differently from the parents of overweight children. They didn't. The study found minimal to non-existent differences between the two groups.

One important risk factor remained seriously overlooked by parents in both groups: physical activity. Only 7 percent of parents in the healthy-weight group and 8 percent in the overweight group cited lack of physical activity as a top driver of unhealthy weight.

Recent studies have shown that few preschoolers achieve healthy levels of activity, and most remain sedentary 85 percent of the time, the investigators say. The results of the study suggest that parents undervalue physical activity in an age group often perceived as "active enough," and alerting parents to the risks of inactivity is critical in obesity prevention, according to Janet Serwint, M.D., of Johns Hopkins Children's Center.

"The importance of physical activity and age-appropriate exercise is one area where we could step up educational efforts," Serwint said. "Pediatricians should discuss specific and age-appropriate activity goals during well-child visits."

Nearly 40 percent of parents in both groups identified buying and preparing unhealthy food as the top contributor to weight problems at an early age. Similar numbers of parents in both groups (23 percent and 31 percent) cited using food as a reward for good behaviour as a risk factor for weight problems. A nearly equal proportion of parents in both groups (25 percent and 23 percent) said that asking the child to finish food on the plate was the most critical contributor to overweight or obesity.

Importantly, one-third of parents from both groups (35 percent and 33 percent) identified lack of control over the child's food choices as the top barrier to healthy weight -- a notable finding, the researchers say, given that most preschool children spend most of their waking hours in daycare or with alternate caregivers.

"Daycare providers, grandparents and others involved in a child's care are often just as important in achieving healthy-weight goals as the parents themselves, and parents should be encouraged to provide specific dietary and activity instructions to these influential caregivers," Hernandez said.

Co-investigators on the study included Tina Cheng, M.D. M.P.H., and Darcy Thompson, M.D. M.P.H., both of Johns Hopkins.

The research was funded by The Thomas Wilson Sanitarium for Children of Baltimore City.