It's pretty well known that it's not just how much we eat, but also the caloriesthe food energy in the portions servedthat make weight control a challenge. However, until recently, the role that food energy density plays in young children's physiological response to portion size has been unproved.
Now a study at the Agricultural Research Service (ARS) Childrens Nutrition Research Center (CNRC), Houston, Texas, has shown that serving large portions of energy-dense foods at meals equates to substantial extra calories consumed by U.S. preschoolers.
Since the 1970s, average portion sizes of foods consumed both inside and outside the home have been steadily increasing. Previously reported research suggested that doubling the portion size of a preschooler's entree would increase the childs total calories consumed at a meal by 15 to 39 percent. For this CNRC study, 53 children were selected from the Houston area28 girls and 25 boys, aged 5 to 6 and representing a wide range of body mass indexes.
The researchers recorded each child's weight and height and noted each participant's food preferences at the beginning of the study. Over the next four weeks, researchers served a special macaroni-and-cheese entree to the children in either one- or two-cup portions and prepared with either a traditional-energy density of 1.3 kilocalories per gram, or a high-energy density of 1.8 kcal/gram by adding extra fat.
Results showed that children ate one-third more entree calories when either the energy- dense version or the large portions was served. However, combining the larger portions with the higher energy added the most calories to the meal. When children were served a large portion of the energy-dense entree, they ate 75 percent more entree calories and 35 percent more total calories at the meal.
These findings provide new evidence that portion size and energy density act additively to increase caloric intake at meals among preschool-age children.