CHAMPS is the first study, to our knowledge, to examine how dietary patterns affect the weight status of children with ASD compared to typically developing children. Parental reports, clinical reports, and research studies have suggested that children with ASD are selective eaters. Specifically, two studies show that children with ASD have a preference for starchy foods and energy-dense foods such as chicken nuggets, hot dogs, cake, French fries, macaroni, pizza, and ice cream over other food groups (Ahearn, et al., 2001
; Schreck & Williams, 2006
). Our results are consistent with these findings, in that children with ASD were found to have more energy dense dietary intake patterns compared to typically developing children. On average, children with ASD consumed significantly more juice and sweetened non-dairy beverages and snacks and significantly fewer servings of vegetables than typically developing children.
Although food selectivity might be expected to limit intake and result in inadequate weight gain, we hypothesized that higher intake levels of energy dense foods (juice and sweetened non-dairy beverages, snacks, and “kids’ meals”) and lower intake of fruits and vegetables in children with ASD compared to typically developing children would be associated differentially with BMI z-score across groups. This hypothesis is consistent with the findings that children with ASD prefer energy dense foods (Ahearn, et al., 2001
; Schreck & Williams, 2006
) along with previous findings that energy dense foods are associated with increased caloric intake (Rolls, Drewnowski, & Ledikwe, 2005
). Our results do not support this hypothesis, however. First, in our multivariate analyses, interaction terms between each individual dietary pattern and group (autism status) were non-significant for all food patterns, suggesting that the association between each dietary pattern and BMI z-score does not depend upon autism status. Further, juice and sweetened non-dairy beverages, snacks, and energy-dense “kids’ meals” were not associated with BMI z-score. We considered this to be an unexpected finding given that, on average, children with ASD consumed four servings of snack foods per day and 2.6 servings of juice and sweetened non-dairy beverages and typically developing children consumed three servings of snack foods per day and 1.7 servings of juice and sweetened non-dairy beverages.
The finding that juice and sweetened non-dairy beverages were not associated with BMI z-score in our study is not consistent with several previous studies that have found an association between sugar-sweetened beverage consumption and overweight and obesity (Ebbeling, et al., 2006
; Lise, et al., 2007
; Ludwig, et al., 2001
). A recent study found that sugar-sweetened beverage intake accounts for between 10% to 15% of caloric intake in typically developing children and adolescents in the U.S. (Wang, et al., 2008
). Decreasing consumption of sugarsweetened beverages is an established modifiable risk factor for overweight and obesity in typically developing children (Wang, et al., 2008
). Additionally, sweetened beverage consumption reduces intake of important nutrients (Vartanian, Schwartz, & Brownell, 2007
) and is associated with lower bone density in female adolescents (Wang, et al., 2008
). While our results are unexpected, it is possible that our study was not powered to detect this association, that inclusion of sweetened beverages (both with natural and added sugars) in our analysis, as opposed to including only those with added sugars, led to different results, that our sample of typically developing children are different from other typical children, or that these beverages contribute “extra” calories in typically developing children and displace other foods in the diets of children with ASD. Regardless, the finding that children with ASD in our study consumed almost three sweetened-beverages per day suggests that further research is needed to better understand how intakes of juice and sweetened non-dairy beverages affects the long-term health and weight status of this population of children.
Perhaps most unexpected was the finding that fruit intake as well as fruit and vegetable intake were positively associated with BMI z-score when controlling for ASD and parental obesity. We examined the combined fruit and vegetable category because dietary guidance often focus on them as a single dietary target (Must, et al., 2009
; Sherry, 2005
). We examined them separately as well because other researchers have found that patterns of consumption are often dissimilar for children (Cooke, et al., 2004
; Gibson, Wardle, & Watts, 1998
). While we did not anticipate that increased fruit and vegetable consumption would be associated with increased BMI z-score in our sample, it may be a chance finding or it may be a result of reverse causation, in that parents of heavier children may encourage greater consumption of fruits and vegetables.
Several limitations of this study are noteworthy. First, our data are cross-sectional, such that we cannot make any conclusions on the directionality or causality of associations between dietary patterns and weight status in these two groups. Further, we did not use a probability sample to select children (parents self-selected based on their interest in their topic of the study), we limited the sample to exclude individuals with chronic disease or illnesses that affect food intake as well as those who take medications that alter appetite, and rates of overweight and obesity in our sample are lower than the national prevalence estimates (Ogden, et al., 2010
). Therefore, the generalizability of our findings may be limited. To limit selection bias, we developed recruitment materials that described our study as one designed to explore the mealtime and activity patterns of children with and without autism. It is possible, however, that parents who describe their children as selective or picky eaters or who were concerned about their child’s lack of variety may have been disproportionately attracted to our study. Although we chose to explore the dietary patterns that have been previously identified in the childhood obesity literature (Must, et al., 2009
; Sherry, 2005
); our dietary measurements did not include all of the dietary risk factors that have been found to be associated with obesity. Furthermore, our instrument did not permit us to separate beverages with added sugars from other non-dairy beverages such as fruit juice. Thus, it is possible that other aspects of diet such as frequency of fast food consumption, sugar-sweetened beverage consumption, and portion size may play a role in obesity development in children with ASD.