(HealthDay) -- If you're trying to get your child to drop a few pounds, here's some food for thought: A new study finds that among three types of diets, kids preferred the one emphasizing foods that don't cause blood-sugar imbalances.
Kids also lost weight on the other two diets, however.
"We know the diets are effective. The question now is how we can get people to follow them," said study lead author Shelley Kirk, a dietitian and assistant professor of clinical pediatrics at the University of Cincinnati College of Medicine.
About 20 percent of children aged 6 to 11 in the United States are obese, which is a step beyond simply being overweight, according to statistics from the U.S. Centers for Disease Control and Prevention. The rate is similar in adolescents aged 12 to 19.
In the new study, researchers examined 85 obese 7- to 12-year-olds who accepted an assigned diet for a year. The kids had weekly dietary counseling and biweekly exercise sessions for the first three months, and then were on their own for the remaining nine months.
One of the diets is similar to the Atkins diet for adults, and focused on very low carbohydrate consumption and a lot of high-protein foods. Another diet focused on foods with low glycemic indexes (such as fruit, nonstarchy vegetables, whole grains, poultry and fish) that are less likely to cause blood-sugar levels to fluctuate. The third diet focused on controlling food portions and making sure calories overall were 55 percent to 60 percent carbohydrates, 10 percent to 15 percent protein, and 30 percent fat.
The researchers found that the participants on average lowered their body mass index (BMI) -- a measurement of body fat based on height and weight -- and the percentage of fat in their bodies. Their waist sizes didn't decrease after a year, but it's not clear if that's because they grew.
The children had the most difficulty following the low-carbohydrate diet and the easiest time with the low-glycemic diet, Kirk said.
Overall, most of the kids lost weight on the diets, Kirk noted.
Cathleen Davis, a clinical dietitian and nutritionist who works with children at Good Samaritan Hospital Medical Center in Babylon, N.Y., applauded the study and explained why the diets might have differed in popularity.
She said the portion-controlled and low-glycemic diets are probably better tolerated "because they both are more mainstream diets that the parents would be familiar and comfortable with."
What should you do if you'd like to put your child on a diet?
"Ask your pediatrician about local reputable programs and look on Eatright.org to find a registered dietitian serving your area," Davis said. "Make tiny changes and expect bad days -- absolutely no one eats perfectly 100 percent of the time. And be very careful of programs that push supplements, make any type of claim for immediate success and don't have licensed credentials."
The study was released online March 1 in advance of publication in an upcoming print issue of the Journal of Pediatrics.
Explore further: Desserts with a low glycemic index may benefit weight-loss efforts for obese children
For more about kids and obesity, try the U.S. Centers for Disease Control and Prevention.