Menna Price

Food-specific response inhibition, dietary restraint and snack intake in lean and overweight/obese adults: a moderated-mediation model

Background/Objectives:The relationship between response inhibition and obesity is currently unclear. This may be because of inconsistencies in methodology, design limitations and the use of narrow samples. In addition, dietary restraint has not been considered, yet restraint has been reported to moderate performance on behavioural tasks of response inhibition. The aim of this study was to investigate performance on both a food-based and a neutral stimuli go/no-go task, which addresses current design limitations, in lean and overweight/obese adults. The moderating role of dietary restraint in the relationship between body composition, response inhibition and snack intake was also measured.Subjects/Methods:Lean and overweight/obese, males and females (N=116) completed both a food-based and neutral category control go/no-go task, in a fully counterbalanced repeated-measures design. A bogus taste-test was then completed, followed by a self-report measure of dietary restraint.Results:PROCESS moderated-mediation analysis showed that overweight/obese, compared with lean, participants made more errors on the food-based (but not the neutral) go/no-go task, but only when they were low in dietary restraint. Performance on the food-based go/no-go task predicted snack intake across the sample. Increased intake in the overweight, low restrainers was fully mediated by increased errors on the food-based (but not the neutral) go/no-go task.Conclusions:Distinguishing between high and low restrained eaters in the overweight/obese population is crucial in future obesity research incorporating food-based go/no-go tasks. Poor response inhibition to food cues predicts overeating across weight groups, suggesting weight loss interventions and obesity prevention programmes should target behavioural inhibition training in such individuals.

A dual-process approach to exploring the role of delay discounting in obesity

Delay discounting of financial rewards has been related to overeating and obesity. Neuropsychological evidence supports a dual-system account of both discounting and overeating behaviour where the degree of impulsive decision making is determined by the relative strength of reward desire and executive control. A dual-parameter model of discounting behaviour is consistent with this theory. In this study, the fit of the commonly used one-parameter model was compared to a new dual-parameter model for the first time in a sample of adults with wide ranging BMI. Delay discounting data from 79 males and females (males=26) across a wide age (M=28.44years (SD=8.81)) and BMI range (M=25.42 (SD=5.16)) was analysed. A dual-parameter model (saturating-hyperbolic; Doya, [Doya (2008) ]) was applied to the data and compared on model fit indices to the single-parameter model. Discounting was significantly greater in the overweight/obese participants using both models, however, the two parameter model showed a superior fit to data (p<0.0001). The two parameters were shown to be related yet distinct measures consistent with a dual-system account of inter-temporal choice behaviour. The dual-parameter model showed superior fit to data and the two parameters were shown to be related yet distinct indices sensitive to differences between weight groups. Findings are discussed in terms of the impulsive reward and executive control systems that contribute to unhealthy food choice and within the context of obesity related research.

Snack intake is reduced using an implicit, high-level construal cue.

OBJECTIVES Priming a high level construal has been shown to enhance self-control and reduce preference for indulgent food. Subtle visual cues have been shown to enhance the effects of a priming procedure. The current study therefore examined the combined impact of construal level and a visual cue reminder on the consumption of energy-dense snacks. METHOD A student and community-based adult sample with a wide age and body mass index (BMI) range (N = 176) were randomly assigned to a high or low construal condition in which a novel symbol was embedded. Afterward participants completed a taste test of ad libitum snack foods in the presence or absence of the symbol. RESULTS The high (vs. the low) construal level prime successfully generated more abstract responses (p < .0001) and reduced intake when the cue-reminder was present (p = .02) but not when it was absent (p = .40). CONCLUSIONS Priming high construal level thinking reduces consumption of high energy dense snacks in the presence of a visual cue-reminder. This may be a practical technique for reducing overeating and has the potential to be extended to other unhealthy behaviors. (PsycINFO Database Record

Impulsivity, eating behaviour and performance on a delay discounting task

Impulsivity is related to a number of addictive behaviours, including drug and alcohol use. Individual differences in impulsivity may explain why some people are able to stick to long-term health goals whilst others are susceptible to temptation. In the modern food environment with an abundance of widely available tempting foods the ability to self-regulate is critical for successful control of eating behaviour. In this study, the relationship between the ability to delay gratification and eating behaviour is explored using a delay-discounting task. This task has been shown to demonstrate the extent to which individuals can inhibit immediate reward in pursuit of more adaptive delayed goals. Male and female participants were tested on a monetary delay-discounting task and a trail making task (measure of executive function) and completed a number of self-report measures of eating behaviour (Power of Food Scale, Dutch Eating Behaviour Questionnaire, Yale Food Addiction Scale) and impulsivity (BIS-11). Height, weight and dieting history were also recorded to get an accurate measure of BMI and current dieting status. Based on previous findings reported by Applehans et al. (2011; Obesity, 19, 2175–2182) we suggest that impulsivity and performance on the delay discounting task will predict eating style and we will explore the relationship between the ability to delay gratification and BMI. The results will be discussed in the context of the role of top-down processes in the cognitive control of eating.