LAS VEGAS — There are at least six behavior change strategies physicians can recommend to prevent child and adolescent obesity, Dr. William H. Dietz said at a meeting sponsored by the American Academy of Pediatrics' California Chapters 1, 2, 3, and 4 and the AAP.
“Reasonable scientific certainty” exists for three of the six strategies, said Dr. Dietz, director of the division of nutrition and physical activity at the Centers for Disease Control and Prevention, Atlanta.
These well-documented strategies are:
▸ Increase physical activity. Emerging evidence regarding the pediatric population suggests that physical activity can reduce obesity-associated comorbidity, particularly glucose intolerance and hyperlipidemia, Dr. Dietz said.
“So if you are obese, inactive, and have elevated triglycerides, increased physical activity will improve your triglyceride level,” he said. “It can also raise your HDL and lower your LDL.”
He added that about 10 years ago, 20% of children walked to school. Today that figure is less than 12%.
▸ Reduce television viewing time. According the Kaiser Family Foundation, 17% of children and adolescents are watching 5 or more hours of television per day.
“Even in the heaviest adolescent computer users, computer time pales by comparison to sedentary [television viewing] time,” Dr. Dietz said. “We have [found] a linear relationship between the amount of television a child watches and the prevalence of overweight.”
▸ Promote breast-feeding. Three metaanalyses in the medical literature have demonstrated that breast-feeding appears to reduce early childhood overweight.
Dr. Dietz defined the next three interventions as “promising. Characteristic of these strategies is that there's no absolute impact for any of them,” he said.
The three promising strategies are:
▸ Increase fruit and vegetable consumption. This dietary factor “appears to have an impact on satiety by virtue of the volume of foods that you consume,” Dr. Dietz explained.
“Satiety does not appear to be regulated by calories. It appears to be regulated by the volume of food. Therefore, food of low caloric density that is high [in] water content is more filling,” he said. “However, data is still lacking for the evidence that increasing [intake of] fruits and vegetables helps reduce weight or that people who have an increased fruit and vegetable intake have a lower risk of being obese.”
▸ Reduce soft drink consumption. A number of studies have linked soft drink consumption to increased weight gain. Yet “we don't yet have studies which demonstrate that reduced soft drink intake is a good way to control weight,” Dr. Dietz noted.
▸ Reduce portion size. This strategy “has a very robust impact on food intake,” he said. “The larger the portion an individual is exposed to, the more likely they are to overeat. We don't have good data that control of portion size is an effective way to reduce weight, but it is a logical potential strategy.”
“One of the problems is a lack of consistent messages,” he said. Young people need to hear a message from their physician, and then have that same message reinforced by what they hear in school, in the community, and from their parents.
Awareness of the problem of obesity among children and adolescents in the United States is starting to plateau, he said.
“I don't think we yet have strategies as effective as those which have been employed against tobacco [use]. Per capita cigarette consumption didn't decline because of a single intervention but because of multiple overlapping interventions,” Dr. Dietz said. “I think interventions with respect to obesity are going to be found in the clinical arena as well as in the schools and communities. We need more communication strategies and advocacy on your part.”
'Satiety does not appear to be regulated by calories. It appears to be regulated by the volume of food.' DR. DIETZ