Feeding/Eating Issue Outcomes

Suboptimal health outcomes are common in individuals with autism. Studies have found an increased risk for obesity, high cholesterol, hypertension, and diabetes in individuals with ASD compared to the general population (2:50). Wallace discusses diminished nutritional intake (4:00), hyperfocus on exercise (4:10), and appetitive traits as contributors to poor health outcomes. Food neophobia (FN), or a fear of trying new foods, is a common and seemingly adaptive appetitive trait of early eating that generally diminishes across child development (5:40). However, FN and other selective eating symptoms often persist into adulthood in autistic individuals and interfere with everyday function (7:20). 

Sensory and Cognition

Wallace examines sensory processing differences and behavioral/cognitive inflexibility as potential drivers of persistent selective eating in autism (9:18). He presents studies on the possible causes of food selectivity (9:50) and the clinical significance of Avoidant Restrictive Food Intake Disorder (ARFID) in autism (11:40). Other selective eating symptoms like eating in the absence of hunger (EAH) are scarcely studied in ASD (14:10). The speaker outlines two new studies that assess the relationship between EAH and 1) cognitive/behavioral correlates in ASD (15:00) and 2) body mass index (BMI) (17:55). Findings reveal that EAH is positively associated with behavioral inflexibility and BMI and that EAH is more prevalent in individuals with ASD than the general population (21:18).  

The speaker defines selective overeating (a new autism subtype) as the co-occurrence of picky eating and overeating (25:56). A novel study using parent ratings of autistic versus typically developing children found a greater number of children with ASD linked to selective eating and selective overeating. Further, Wallace explains, autistic children with EAH had significantly higher rates of selective eating than children without EAH (26:00). Combining these findings with those of the first two studies, Wallace asserts that increased behavioral inflexibility is most elevated for individuals who engage in selective overeating (28:50). 

Individuals with autism have divergent sensory processing experiences across all sensory systems. Therefore, Wallace states, taste perception/processing is a prime candidate for assessing neural correlates related to eating behaviors (30:20). Multiple studies suggest that while individuals with ASD can perceive taste, they struggle with taste identification or sensory integration (31:13). The speaker defines sensory integration difficulties as a cortical issue and briefly describes the cortical taste pathway (33:37) and using functional magnetic resonance imaging (fMRI) to assess brain blood flow in response to stimuli (34:33). Wallace outlines a 2018 study using gustatory mapping (fMRI) (37:45) and self-reports (37:02) to assess (35:50) response to tastants (taste samples) in the gustatory cortex and their relation to self-reported taste reactivity in autism. 

Researchers found no differences in neural response to tastants between autism and typically developing age-matched groups (39:15). They also found no association between self-rated taste reactivity and brain response to sweet tastants in the neurotypical group. However, autistic individuals who self-rated as highly taste-reactive showed a strong positive relationship with gustatory response to the sweet tastants relative to the neutral flavor (40:13). Wallace explains that although there is no evidence of overall atypical gustatory cortical function in autism, findings suggest that individual differences in self-rated taste reactivity modulate activity in the gustatory cortex. The speaker posits that these findings also suggest atypical brain functions for individuals with autism and food selectivity that could impact BMI through diet variation (41:24). 

Conclusions

Wallace summarizes his presentation, noting that more work is needed to establish longitudinal relationships between eating-related behaviors, their causes, and their outcomes. He touches on the need for more interventions for food-related behaviors to improve physical health and overall quality of life for individuals with autism (42:50). Wallace discusses the limitations of the presented studies (43:50) and provides links to more information (44:50) before the question and answer session (45:16).