Body Mass Index and stimulus control: Results from a real-world study of eating behaviour

Background: Evidence suggests decisions about when, what, and how much to eat can be influenced by external(location, food outlet presence, food availability) and internal (affect) cues. Although the relationship betweenstimulus control and obesity is debated, it is suggested that individuals with higher BMIs are more driven by cuesto eating than individuals in the healthy-weight range (HWR). This study investigates the influence of stimuluscontrol on real-world food intake, and whether stimulus control differs by BMI. It was hypothesised that,compared to those in the HWR, eating among individuals with higher BMIs would be under greater stimuluscontrol.Method: 74 participants (n = 34 BMI n = 40 BMI > 24.9) recorded food intake for 14 days usingEcological Momentary Assessment. Participants also responded to 4–5 randomly-timed assessments per day.Known external and internal eating cues were assessed during both assessment types. Within-person logisticregression analyses were used to predict eating vs. non-eating occasions from stimulus control domains.Findings: Results support the hypothesis that eating was influenced by stimulus control: food availability, affect,time of day, and location significantly distinguished between eating and non-eating instances (AUC-ROC = 0.56-0.69, all p's Discussion: Results support the notion of stimulus control in shaping eating decisions. Differences in levels ofstimulus control between participants in the HWR compared to those with a high BMI suggest that dietaryimprovement interventions may be more effective when they are tailored to the individual and consider environmental influences on eating behaviour