Increased total daily energy intake by children from 1977 to 2006 was associated with a major shift toward increased calories consumed away-from-home (+255 kcal/d) while the number of calories eaten at home has declined only slightly (−76 kcal/d). From 1994 to 2006, the sources of food eaten at home and away-from-home have shifted. Stores maintained their role as the predominant source of energy for children, but the proportion of energy from fast food and restaurants increased. Energy intake from school declined. Within this broad shift in children’s intake from CSFII94 to NHANES03, important changes occurred in the sources of food consumed at home toward an increasing role for fast foods. For food eaten away-from-home, the increasing calorie intake from store-bought foods drove the overall increase in kcal/d. In 2006, stores were the largest source of calories for foods eaten at home and for foods eaten away-from-home. A larger percentage of store-bought food is eaten away-from-home. When referring to location of preparation, fast food was the largest provider of calories prepared away-from-home in 2006. The increase in fast food intake arose from an increase in fast food consumed at home.
Previous studies demonstrated that children’s energy intake increased from 1977 to 1998, but no prior works have examined the energy increase by eating location (1
). While the large increase in the percentage of total energy intake derived from away-from-home foods is well documented (1
), away-from-home foods are defined in these studies as food prepared away-from-home, regardless of eating location. Our analysis by eating location shows that increased energy intake results from an increase in calories consumed away-from-home while energy content of foods eaten at home has remained approximately constant. This finding is supported by studies suggesting that overweight individuals do not compensate for increased consumption at away-from-home meals by decreasing intake for the remainder of the day (8
The present study identifies a shift in the source of both foods eaten at home and away-from-home for children. Previous studies that describe the decrease from 1977 to 1998 in “home” foods, defined as store-bought foods eaten at home, did not fully illustrate the trends in store-bought foods (1
). This study shows that the overall intake from stores did not decrease from 1994 to 2006, only the contribution of store-bought foods to intake at home decreased. The overall intake from stores was maintained by a major shift toward increased intake of store-bought foods away-from-home. Previous studies documented a minor role for store-bought foods eaten away-from-home that showed little or no change as a percentage of daily intake from 1977 to 1998 (1
Of note, this study updates this trend to reveal that the main increase in foods eaten away-from-home, and thus in overall energy intake for children, results from a dramatic increase in store-bought foods eaten away-from-home (: +4.5 %). Further studies of store-bought foods and their variation in energy density and nutrient composition by location of consumption are warranted to determine the impact of this shift upon energy intake. Store-bought “home” food is increasingly ready-prepared, as retail stores are increasing their selection of these “hot-and-ready” choices and spending for these types of foods has increased (24
However, only the proportion of ready-to-eat foods prepared at restaurants, fast food, schools, and vending machines can be estimated using nationally representative survey data, whereas the percentage of store-bought foods prepared away-from-home cannot be estimated. Thus, the actual proportion of home food versus away-from-home food, as defined by source of preparation, should be evaluated using commercially prepared data sets for store purchases in addition to the NHANES data. Moreover, increases in store-bought, ready-prepared foods should be examined by eating location to evaluate their contribution to the large increase in store-bought foods eaten-away from-home.
Consideration of eating location also revealed more detail about the upward trend in fast food intake. These results agree with prior studies of the increasing role of fast food in children’s diets, which is contributing to the major shift toward eating foods prepared away-from-home (1
). This study is the first to examine the increase in fast food intake by location of fast food consumption. Our study shows that the increase in calories from 1994 to 2006 results entirely from an increase in fast food eaten at home. Almost ½ of all fast food calories eaten by children 2 to 18 in 2006 were consumed at home, which represents 6.1% of all kcal/day. Further studies are needed to examine portion sizes and the contribution of meals versus snacks to fast food purchased as “to go” or drive-thru orders eaten at home.
The role of schools has also changed greatly. While schools were by far the largest away-from-home food source in 1977, fast food had increased to become an equal contributor to children’s energy intake by 1998 (2
). School feeding programs are viewed as a major target for addressing childhood obesity (26
). Most US public schools participate in the National School Lunch Program and 80% participate in the School Breakfast Program (14
). For preschoolers and young children, school was the largest source of away-from-home foods in 1994–98. This study updates this finding for 2006 and shows that fast food has now surpassed school foods as the main away-from-home source of preparation for all age groups of children.
The extremely small percentage of children’s energy intake from vending machines is consistent with previous studies (2
), yet many school food policies aim to improve children’s diets by regulating vending and other “competitive foods” (31
). While limiting children’s access to low-nutrient, energy-dense foods in vending machines may decrease their intake of these items in schools, the impact of removing vending machines on total energy intake appears small but still represents an important education and policy tool (26
Overall, our results suggest that the increases in energy intake by children are fueled by greater consumption of foods prepared away-from-home. The location/source categories showing the greatest increase in %kcal/d from 1994 to 2006 were fast food eaten at home and store-bought food eaten away-from-home. The increase in store-bought foods eaten away-from-home likely represents an increase in store-prepared foods, and this is a previously unidentified and un-quantified new source of calories prepared away-from-home. As noted, further research is necessary to confirm this assumption. To fully capture increases in foods prepared away-from-home and decreases in home food preparation, future investigations must quantify store-prepared foods.
This study has important limitations, mainly in relation to the use of different dietary surveys. Early methodological changes in diet measurement were addressed by a bridging study, which showed no major shifts in basic eating patterns (34
). No problems were reported with results by eating location, so comparisons over all time points are valid. The largest changes in survey methodology occurred between the 1980s and 1990s with the introduction of the multiple pass method. No bridging study exists to show the consequences of these methodological changes (35
). Although underreporting has increased over time, there is no evidence of bias in reporting by eating location (36
). Under-reporting of less healthful foods eaten away-from-home would cause the results presented here to be conservative estimates. Although the same approach was used to collect data for each age group, there is no research about the possible changes over time in parental understanding of child eating patterns. Long-term trends in the location of food preparation were not examined because of the incomplete source information for foods eaten at home collected by NFCS77 and CSFII89.
As noted, the total percentage of energy from foods prepared away-from-home, including those prepared at stores, cannot be measured. By including all store-bought foods within a Home/Store category that is not considered as food prepared away-from-home, store-prepared foods is being improperly considered as home-prepared. The percentage of foods prepared away-from-home is underestimated, and the amount of home-cooking is over-estimated. Thus, the increase in % kcal/d from foods prepared away-from-home might be even greater than that estimated by this analysis. Further, no information was collected about how much store-bought, store-prepared food is eaten at the store and how much is eaten at home. Because this study did not assess the quality of foods eaten or obtained away-from-home, further research is necessary to determine the impact of away-from-home foods upon diet quality. Finally, without information documenting the location of vending machines, foods from vending machines located on school facilities cannot be included in school intake.
Overall, this study highlights the continuing rapid shifts in the sources of food for children in the US—both where it’s eaten and where it’s prepared. These results underscore the need to deepen our understanding of food preparation and consumption patterns, and further pinpoint where research and programmatic activity should focus. The differences in energy intake by eating location revealed in this analysis demonstrate that eating location is an important factor in the diet of American children. Further studies of children’s diet focusing on energy intake and nutritional quality by eating location are warranted, particularly for store-purchased food overall, carry-out or drive-thru fast food, and hot-and-ready vs. home-prepared foods. Future research should examine the macronutrient distribution of calorie intake by eating location and food source and the impact of body mass index upon such intake. By determining the importance of both where children eat and where their food is prepared, this study helps elucidate where children are obtaining their calories. Because of the increased energy intake and lower nutritional quality associated with away-from-home prepared foods, such insight can be used to focus future efforts to reduce calorie intake and improve dietary quality for American children (4