July 16, 2004

Shapedown study puts obesity to the test

Featured Image

Registered Dietitian and certified Shapedown instructor, Heather Holden,
(center) teaches Will Hoffman (left) and Breana Stallworth (right) how to be more active. /Photo by Dana Johnson

Shapedown study puts obesity to the test

Will Hoffman is a pretty typical child. The 9-year-old attends Davidson Academy and loves all sports, especially baseball. He is tall for his age at almost 5 feet, and he is also among the increasing number of children who are overweight.

Will ranks above the 95th percentile for weight in children of his age, meaning he’s heavier than 95 percent of kids his height and age. While the easygoing fourth grader isn’t concerned about his weight, he knows his mother is.

His mother, Peggy, enrolled her son and herself in a weight-management program at Vanderbilt called Shapedown, but they got more than either expected. They were offered the chance to take part in a study that could help find solutions for the national epidemic of childhood obesity.

Researchers at Vanderbilt Children’s Hospital are working through the Shapedown program to conduct a pilot study examining exercise, diet and behaviors of obese children and their parents. Specifically, the researchers hope to find out whether short bursts of activity — 10 minutes three times a day — helps kids maintain a healthy weight better than the current standard of 30 minutes of continuous exercise most days of the week.

“The current recommendations for exercise in children are taken from what we know about adults, but the evidence, even for adult weight loss recommendations, is inconsistent,” said Sari Acra, M.D. “So to help answer this question in children, we wanted to get very accurate data by using technical innovations that have been developed over the last several years.”

Acra is the principal investigator for the study and a pediatric gastroenterologist at Vanderbilt Children’s Hospital.

He collaborated with Kong Chen, M.D., director of the Energy Balance Lab at VUMC for the study. Chen has developed a number of techniques to study the way people’s bodies use calories. The two decided to use newly-designed research tools called “activity monitors” to keep very careful track of the exercise patterns of the children in the study. They could then take the technical data and compare that with valuable information normally gathered in the Shapedown program.

“We had anecdotally observed that children naturally exercise in short bursts, nothing sustained,” Acra said. “My co-principal investigator, Kong Chen and I designed the study to look at the theory that if we modeled exercise after the natural behavior of children we might get better success in weight control in the long run.”

The new technology Acra uses in his study is a highly accurate activity monitor, which has been used in several adult studies.

“It’s called the RT-3 tracker,” said Meagan Neumann, co-investigator of the study and Licensed dietitian at the Energy Balance Lab. “This monitor is able to measure acceleration and movement in three axis where most just tell us up and down. This one is better at entire movement: frequency, duration and intensity; so it gives more accurate information.”

The device also keeps a continuous record, even when the child is at rest.

“We wanted to measure activity throughout the day and find out if the exercise plan altered activity at other times,” Acra said. “For example, if a child was exercising with high intensity for 30 minutes continuously, we wanted to know if they compensated by being less active than normal the rest of the day.”

At the Shapedown program, offered through the Nutrition Clinic and conducted at the Kim Dayani Center, little was different for the classes involved in the study from a normal class. In the 10-week program, a child and parent come together to the Dayani center, one evening a week, for instruction on exercise, nutrition and tips to improve health habits. The research team worked with the certified Shapedown instructors Heather Holden and Andrea Klint, who are also registered dietitians, to gather data.

“The biggest change is that the children are divided into two exercise groups: one group exercises for 10 minutes three times a day while the other exercises for 30 continuous minutes,” Klint said. “Halfway through the 10 weeks, the groups switch exercise routines.”

Will wore his activity monitor for most of his waking hours. On Monday evenings, he and his mother would arrive for Shapedown, weigh in and download their RT-3 trackers. The weigh-in is part of the regular program, while the download of the information on their RT-3 trackers is purely for the study. A printout of the data appeared as a series of spikes on a graph.

“Aside from the data, it’s also a motivating tool,” Klint said. “The kids like to see the peaks and say, ‘Oh yeah, that’s the day I went bike riding at the park.’ Then they even get where they almost compete with themselves, trying to get those peaks higher and more frequent.”

Researchers expect to see that as kids get into better shape, their perception of activity would change because it becomes easier as their bodies get more physically fit.

“I would like to know how well the kids comply with the 10- minute versus 30-minute programs when you take into account their current weight,” Klint said. “It may be that if they weigh above the 95th percentile they might be more compliant with the shorter duration exercise, then as they develop better tolerance, they might grow to prefer the 30-minute time period.”

At the beginning of the study, Will got a blood test, blood pressure check, one-mile endurance test, along with height and weight recordings. All those tests were repeated again at the end of the 10 weeks.

Will says his big accomplishment was being able to be more active with less effort. He has had some breakthroughs that his mother believes will help long term.

“At first I was frustrated that we weren’t losing a pound a week I had as my goal,” said Hoffman. “But at the end of 10 weeks, I realized it had been a long time since we’d been able to hold his weight steady. He had lost an inch around his waist and his blood pressure and exercise tolerance improved significantly. I think we’ve made changes we can stick to long term.”

Acra and his team are hoping to enroll 30 parent/child pairs. They are a little more than halfway there and hope to complete enrollment by the end of the year.

The Acra/Chen study will work with Shapedown one final time in September.

Anyone with a 9- or 10-year-old child who is obese, interested in participating can call Megan Neumann at 343-8497.