Effects of Age on Children's Intake of Large and Self-Selected Portions
The observation that individuals are susceptible to consuming more calories when offered a large portion of food compared to a standard portion may start in children as young as two years old, according to results from an experimental study. The age at which this phenomenon occurs has been debated in the pediatric nutrition community, with previous research suggesting this effect does not occur until the preschool years.
"Our work indicates that eating behavior is influenced by environmental factors such as portion size from a very young age," said Jennifer Orlet Fisher, Ph.D., assistant professor in the department of pediatrics at Baylor College of Medicine in Houston, TX and a researcher for the USDA Children's Nutrition Research Center, which funded this study. "To help counter this behavior, parents can involve their youngster in portion size selection, which seems to encourage more age-appropriate intake."
The researchers served 75 non-Hispanic white children, age two to nine years old, a dinner meal on three different occasions. The meal consisted of macaroni and cheese, corn, applesauce, carrots, cookies and milk. The macaroni and cheese portions were varied at each meal and were either age-appropriate, doubled in size or determined by the child after helping him/herself from a serving dish containing the double-sized portion.
On average, the children did not finish the age-appropriate sized portion, consuming just over half of it (56 percent). Yet, when served the large portion, the children ate 29 percent more and increased energy intake by 13 percent. The effect was consistent across all ages. The increase in consumption was attributed to the children taking larger bites, rather than more bites, indicating that the amount of food provided a subtle visual cue of how much to eat.
In an analysis of the children who ate more of the large portion than the reference portion, the researchers discovered that the children ate less when they served themselves.
Overweight and obesity has reached epidemic proportions in the United States, as well as worldwide. Data collected by the National Center for Health Statistics indicate that the prevalence of obesity, defined as a body mass index >30 kg/m╡ has increased from 12.8% in 1976-1980 to 22.5% in 1988-1994 and 30% in 1999-2000. Roughly 31% of American adults meet the criterion for obesity - about 59 million American adults. More than 64% of the US adult population have a BMI >=25 kg/m╡. In the past 30 years, the occurrence of overweight in children has doubled and it is now estimated that 16 percent of children in the US are overweight. Increases in the prevalence of overweight are also being seen in younger children, including preschoolers.
While more children are becoming overweight, the heaviest children are getting even heavier. As a result, childhood overweight is regarded as the most common prevalent nutritional disorder of US children and adolescents, and one of the most common problems seen by pediatricians.