State and trait influences on attentional bias to food-cues: The role of hunger, expectancy, and self-perceived food addiction.

Food-related attentional bias (AB) varies both between individuals (i.e. trait differences) and within individuals (i.e. state differences), as a function of a food's momentary incentive value. People with self-perceived food addiction (SPFA) find food particularly rewarding and may therefore demonstrate increased AB to food-related cues, relative to those who do not perceive themselves as food addicts. However, these trait differences may interact with state factors, such as hunger and the perceived availability of food, to differentially affect AB to food-cues. In the current study, female participants (N = 120) completed an eye-tracking task to assess AB to chocolate pictures in which the expectancy of receiving chocolate was manipulated on a trial-by-trial basis (0%, 50%, 100%). Participants were randomly allocated such that half completed the task when hungry (hungry condition), and half completed the task following a lunch meal (satiated condition). Participants also indicated the extent to which they perceived themselves to be 'food addicts' (SPFAs: n = 37; Non-addicts: n = 53; Undecided: n = 28). Consistent with previous findings, there was a significant main effect of chocolate expectancy; food-related AB was greater on 100% and 50% trials, compared to 0% trials. However, there was no effect of hunger condition (hungry vs. satiated) on AB. Contrary to our hypotheses, SPFAs did not show increased AB to food-cues, and this was not moderated by hunger condition or the expectancy information. Exploratory analyses revealed that higher desire-to-eat (DtE) chocolate was associated with increased AB to chocolate pictures. These findings partially support contemporary theoretical models of AB by indicating a key role for state factors (reward expectancy, DtE) in determining AB to food-cues, while a trait factor (SPFA) was not a significant determinant of food AB.

The development and validation of the Addiction-like Eating Behaviour Scale.

BACKGROUND: Overeating and obesity are frequently attributed to an addiction to food. However, there is currently a lack of evidence to support the idea that certain foods contain any specific addictive substance. An alternative approach is to focus on dimensions of observable behaviour, which may underpin a behavioural addiction to eating. To facilitate this, it is necessary to develop a tool to quantify addiction-like eating behaviour, which is not based on the clinical criteria for substance dependence. The current study provides initial validation of the Addiction-like Eating Behaviour Scale (AEBS). METHODS: English speaking male and female participants (N=511) from a community sample completed the AEBS, alongside a range of other health- and eating-related questionnaires including the Yale Food Addiction Scale (YFAS) and Binge Eating Scale (BES). Participants also provided their height and weight to enable calculation of body mass index (BMI). Finally, to assess test-retest reliability, an additional 70 participants completed the AEBS twice, 2 weeks apart. RESULTS: Principle components analysis revealed that a two-factor structure best accounted for the data. Factor 1 consisted of items that referred to appetitive drive, whereas factor two consisted of items that referred to dietary control practices. Both subscales demonstrated good internal reliability and test-retest reliability, and a confirmatory factor analysis confirmed the two-factor scale structure. AEBS scores correlated positively with body mass index (BMI) (P<0.001) and other self-report measures of overeating. Importantly, the AEBS significantly predicted variance in BMI above that accounted for by both the YFAS and BES (P=0.027). CONCLUSIONS: The AEBS provides a valid and reliable tool to quantify the behavioural features of a potential 'eating addiction'. In doing so, the AEBS overcomes many limitations associated with applying substance-dependence criteria to eating.

EffectS of non-nutritive sWeetened beverages on appetITe during aCtive weigHt loss (SWITCH): Protocol for a randomized, controlled trial assessing the effects of non-nutritive sweetened beverages compared to water during a 12-week weight loss period and a follow up weight maintenance period.

BACKGROUND: Acute and medium-term intervention studies suggest that non-nutritive sweeteners (NNS) are beneficial for weight loss, however there is limited human data on the long-term effects of consuming NNS on weight loss, maintenance, and appetite. Further research is therefore required to elucidate the prolonged impact of NNS consumption on these outcome measures. METHODS/DESIGN: A randomized parallel groups design will be used to assess whether regular NNS beverage intake is equivalent to a water control in promoting weight loss over 12-weeks (weekly weight loss sessions; Phase I), then supporting weight maintenance over 40-weeks (monthly sessions; Phase II) and subsequently independent weight maintenance over 52-weeks (Phase III) in 432 participants. A subset of these participants (n=116) will complete laboratory-based appetite probe days (15 sessions; 3 sessions each at baseline, at the start of phase I and the end of each phase). A separate subset (n=50) will complete body composition scans (DXA) at baseline and at the end of each phase. All participants will regularly be weighed and will complete questionnaires and cognitive tasks to assess changes in body weight and appetitive behaviours. Measures of physical activity and biochemical markers will also be taken. DISCUSSION: The trial will assess the efficacy of NNS beverages compared to water during a behavioural weight loss and maintenance programme. We aim to understand whether the impact of NNS on weight, dietary adherence and well-being are beneficial or transient and effects on prolonged successful weight loss and weight maintenance through sustained changes in appetite and eating behaviour. TRIAL REGISTRATION: Clinical Trials: NCT02591134; registered: 23.10.2015.

Empty plates and larger waists: a cross-sectional study of factors associated with plate clearing habits and body weight.

Clearing one's plate out of habit when eating may promote excess energy consumption. This study examined whether plate clearing is related to increased body weight in a sample of young adults. It also sought to identify potential determinants of plate clearing. A cross-sectional design was used in which 385 young adults from a UK university completed self-report measures of plate clearing, weight and height, and demographic characteristics. Plate clearing was predictive of heavier body weight in both unadjusted and adjusted analyses. Parental encouragement to clear one's plate during childhood (retrospectively reported) and personal concerns about food waste were both independent predictors of plate clearing tendencies. Clearing one's plate when eating is associated with heavier body weight, and the prevalence of this behaviour may depend on parenting practices and concerns about food waste. Further work examining the longitudinal effect of plate clearing on weight gain is now needed.

The effects of a priming dose of alcohol and drinking environment on snack food intake.

Alcohol consumption is a potential risk factor for being overweight. We aimed to investigate the effects of an alcohol priming dose and an alcohol-related environment on snacking behaviour. One hundred and fourteen social drinkers completed one of four experimental sessions either receiving a priming dose of alcohol (.6 g/kg) or soft drink in a bar-lab or a sterile lab. Participants provided ratings of appetite, snack urge, and alcohol urge before and after consuming their drinks. Participants completed an ad libitum snack taste test of savoury and sweet, healthy and unhealthy foods before completing the self-reports a final time. Appetite and snack urge increased more following alcohol consumption, and decreased to a lesser extent following the taste test relative to the soft drink. Total calories (including drink calories) consumed were significantly higher in the alcohol groups. There was a marginal effect of environment; those in the bar-lab consumed a higher proportion of unhealthy foods. These effects were more pronounced in those who were disinhibited. While alcohol may not increase food consumption per se, alcohol may acutely disrupt appetite signals, perhaps via processes of reward and inhibitory control, resulting in overall greater calorie intake. Individuals who are generally disinhibited may be more vulnerable to the effects of alcohol and drinking environments on eating behaviour.

Will smaller plates lead to smaller waists? A systematic review and meta-analysis of the effect that experimental manipulation of dishware size has on energy consumption.

It has been suggested that providing consumers with smaller dishware may prove an effective way of helping people eat less and preventing weight gain, but experimental evidence supporting this has been mixed. The objective of the present work was to examine the current evidence base for whether experimentally manipulated differences in dishware size influence food consumption. We systematically reviewed studies that experimentally manipulated the dishware size participants served themselves at a meal with and measured subsequent food intake. We used inverse variance meta-analysis, calculating the standardized mean difference (SMD) in food intake between smaller and larger dishware size conditions. Nine experiments from eight publications were eligible for inclusion. The majority of experiments found no significance difference in food intake when participants ate from smaller vs. larger dishware. With all available data included, analysis indicated a marginal effect of dishware size on food intake, with larger dishware size associated with greater intake. However, this effect was small and there was a large amount of heterogeneity across studies (SMD: -0.18, 95% confidence interval: -0.35, 0.00, I(2) = 77%). Evidence to date does not show that dishware size has a consistent effect on food intake, so recommendations surrounding the use of smaller plates/dishware to improve public health may be premature.

Lack of association between DRD2 and OPRM1 genotypes and adiposity.

BACKGROUND: Dopaminergic and opioid systems are both involved in food intake and appetite control. The dopamine D2 receptor gene (DRD2) and the µ-opioid receptor gene (OPRM1) therefore represent plausible candidates for association with obesity. OBJECTIVE: Previous studies of these variants have yielded inconsistent findings, which are likely due to insufficient statistical power. The aim of the current study was to determine whether, in a large population-based sample, there are associations between adiposity and (i) the A1 (T) allele of the Taq1A polymorphism (rs1800497) in DRD2 and (ii) the G allele of the A118G polymorphism (rs1799971) in OPRM1. STUDY POPULATION: Annual clinic-based measures of body mass index (BMI) and waist circumference were taken from children (N=3720) at 5 measurement time points from ages 7 through to 11 years. BMI was also recorded in their mothers (N=2460) at comparable time points and at pre-pregnancy. All participants were genotyped. Our study was powered (at 80%) to detect per-allele effects on BMI of 0.21 kg m(-2). RESULTS: Our results indicate a lack of association between DRD2 and OPRM1 genotypes and adiposity. Combining the data across mothers and children found per-allele effects on BMI of 0.02 kg m(-2) (95% confidence interval (CI): -0.17, 0.20), P=0.9 for rs1800497 and -0.08 kg m(-2) (95% CI: -0.29, 0.22), P=0.4 for rs1799971. As a positive control, we also examined the effect of FTO genotype over the same time period and confirmed the expected relationship between variability at this locus and higher adiposity. CONCLUSION: Our findings question existing evidence suggesting associations at DRD2 and OPRM1 loci and adiposity. They also highlight the caution required when employing candidate gene approaches to further our understanding of the neurobiology of eating and obesity.

Increasing parental provision and children's consumption of lunchbox fruit and vegetables in Ireland: the Food Dudes intervention.

BACKGROUND/OBJECTIVES: Previous research in the United Kingdom, where there is a school canteen system, has shown that the Food Dudes intervention substantially increases children's fruit and vegetable consumption. The current study evaluated its effectiveness in Ireland where school meals are not provided and children bring food to school in lunchboxes. SUBJECTS/METHODS: Participants were 4- to 11-year-old children attending two primary schools; the schools were randomly assigned to experimental or control conditions (n=228 and 207, respectively). During the 16-day intervention in the experimental school, children watched video adventures featuring the heroic Food Dudes, and received small rewards for eating fruit and vegetables provided. In both schools, parental provision and children's consumption of fruit and vegetables in the lunchboxes were assessed at baseline and 12-month follow-up (Lunchbox measures). Fruit and vegetables were provided in both schools over an 8-day baseline phase and the 16-day intervention, and children's consumption was measured (school-provided food measures). RESULTS: Relative to baseline, consumption of the school-provided foods increased during the intervention in the experimental school (P<0.001), whereas in the control school it showed a significant decline. At 12-month follow-up, parents in the experimental school provided and their children consumed significantly more lunchbox fruit, vegetables and juice relative to baseline and to the control school (P<0.001 in all instances). CONCLUSIONS: The Food Dudes intervention was effective in changing parental provision and children's consumption of lunchbox fruit and vegetables in Ireland.

Increasing children's physical activity: a peer modelling, rewards and pedometer-based intervention.

BACKGROUND/OBJECTIVES: To evaluate a peer modelling, rewards and pedometer-feedback intervention designed to increase children's physical activity and which uses the same behaviour-change principles underlying the Food Dude Healthy Eating Programme. SUBJECTS/METHODS: The study was conducted in two primary schools in Wales. Participants were 47 children (21 boys, 26 girls) from the experimental school and 53 children (29 boys, 24 girls) from a matched control school, aged 9-11 years. Children in the experimental school took part in the intervention; over 8 days they were introduced to fictional role models (the Fit n' Fun Dudes) via visual and audio intervention materials and received small rewards when their daily pedometer step counts increased by 1500 steps per day relative to their baselines. Pedometer measures were taken from children in both schools at baseline, intervention (baseline 2 for the control school) and 12-week follow-up. RESULTS: Among experimental girls, steps per day were significantly higher during the intervention (14 686+/-2540) and at follow-up (13 737+/-3288) compared to baseline (10 864+/-2481, P<0.001) and control girls (P<0.005). Experimental boys showed significantly higher daily steps during the intervention compared to baseline (16 237+/-4204 cf. 13 452+/-3258, P<0.001) and control boys (P<0.005). There were no significant differences between activity levels of experimental and control boys at follow-up. CONCLUSIONS: The intervention resulted in substantial increases in children's physical activity, which was well maintained over a 12-week period in girls.

Increasing children's fruit and vegetable consumption: a peer-modelling and rewards-based intervention.

OBJECTIVE: To evaluate a peer-modelling and rewards-based intervention designed to increase children's fruit and vegetable consumption. DESIGN: Over a 5-month period, children in an experimental and a control school were presented with fruit and vegetables at lunchtime. Children aged 5-7 y also received fruit at snacktime (mid-morning). The intervention was implemented in the experimental school and levels of fruit and vegetable consumption were measured at baseline, intervention and at 4-month follow-up. SETTING: Two inner-city London primary schools. SUBJECTS: In total, 749 children aged 5-11 y. INTERVENTION: Over 16 days children watched video adventures featuring heroic peers (the Food Dudes) who enjoy eating fruit and vegetables, and received small rewards for eating these foods themselves. After 16 days there were no videos and the rewards became more intermittent. MAIN OUTCOME MEASURES: Consumption was measured (i) at lunchtime using a five-point observation scale; (ii) at snacktime using a weighed measure; (iii) at home using parental recall. RESULTS: Compared to the control school, lunchtime consumption in the experimental school was substantially higher at intervention and follow-up than baseline (P<0.001), while snacktime consumption was higher at intervention than baseline (P<0.001). The lunchtime data showed particularly large increases among those who initially ate very little. There were also significant increases in fruit and vegetable consumption at home (P<0.05). CONCLUSIONS: The intervention was effective in bringing about substantial increases in children's consumption of fruit and vegetables.