An article currently in press American Journal of Clinical Nutrition, A team of scientists studied the food intake of preschool children to examine the relationship between factors such as food energy density (ED) or food weight and food energy intake. Their findings indicate that children’s energy intake increases and then decreases with ED, and this plot may be attributed to the fact that high-ED foods are served in limited quantities.
Previous studies have established that at low ED levels, adults consume more food to increase their energy intake. However, after a threshold level, adults begin to adjust their meal size so that they do not suffer from the effects of overeating. However, this raises an interesting question. Can children also change their portion sizes based on energy intake, or does this ability develop with age?
Study: Children’s energy intake generally increases in response to food energy density but varies with the amount and type of food served. Image credit: Created with assistance from DALL·E 3
About the study
To answer the question of whether children, like adults, show a breakpoint in which they adjust their portion sizes in response to increasing ED levels, researchers looked at childcare centers that served preschool children familiar foods and allowed them to select meals and portion sizes. . They conducted two randomized crossover trials over 5 days.
At both centers, staff vary the daily menu in terms of the amount and type of food they serve. The data thus included 30 menus, all of which met the Nutrition Guidelines for Child Care Programs in the United States. In total, the researchers studied 6,355 meals that were given to 94 children aged 3 to 5 years. Participating children did not have dietary restrictions, allergies or other health problems that could have affected their participation.
Meals included ‘main meals’ as well as snacks. Main meals or grains and protein-based ingredients and sides of fruits and vegetables were provided at breakfast, lunch, and dinner. A cereal bar was provided for breakfast. Afternoon and evening snacks included items rich in fruits, vegetables, grains, milk, and meat and meat alternatives.
During this snack, the researcher provided both the low-ED option as well as the high-ED option. To meet nutritional guidelines, high-ED items were provided in smaller amounts, while low-ED items were provided in larger amounts. All food items were carefully weighed to ensure that consumption could be closely monitored. Physical activity performed by children was also logged, and body weight status was calculated. Parents were asked to provide demographic information for their children and to complete a child eating behavior questionnaire.
The researchers analyzed this dataset using linear mixed models with repeated measures to identify the trajectory of the relationship between food energy intake and food ED (both served and eaten).
Of the 94 children, 53% were male and 47% were female. Of the 87 who provided anthropometric data, 13 were classified as overweight or obese, while 2 were underweight. Children were predominantly white (69), with smaller numbers of Asian, black or other ethnic groups.
On average, children consume about 1000 kcal per day, which meets their estimated energy needs (based on children for whom anthropometric data were available). Main meals contribute 43% of daily intake weight, while snacks contribute 24% and milk 33%. On average, main meals contribute half of daily energy intake, while snacks provide 36% and milk 14%. The mean daily ED consumed by children was 1.4 kcal per gram.
During the main meal, the ED consumed by children was slightly lower than the ED they were served. Notably, ED intake was greater than ED served at snack times. This indicates that children prefer high-ED snack items more than low-ED snack items. Energy intake throughout the day was positively associated with menu characteristics such as portion size, ED, and weight of food served. Overall, children’s energy intake increased and then decreased with ED. This plot may be attributed to the fact that the high-ED foods were served in limited amounts and not to the breakpoint seen in adults.
Using food intake measured in preschool children, researchers found evidence that mealtime energy intake increased with food weight and ED, both in terms of foods eaten and served. However, they found no indication that there is a threshold level or break point of ED in unconsciously ingested children, after which they reduce their energy intake. Indeed, it was demonstrated that the availability of high-ED foods was a limitation of intake.
The study was conducted strictly by following all meal times (main meals and snacks) of the children for five consecutive days. However, menus were limited in the availability of high-ED foods, which may not be the case for all children. All participants were also from high-education and high-income families, making the results less generalizable to other groups.
This study provides exciting results on the multivariate relationship between ED intake and food availability. Further studies, the authors hope, will use experimental frameworks to examine these relationships and provide important insights into human nutrition.