Dietary restraint and heightened reactivity to food

Reactivity to food cues in spicy food cravers: Physiological and behavioral responses

In China, the rate of spicy food consumption is rising, and chili pepper is among the most popular spicy foods consumed nationwide. According to the 'cued overeating' model, visual and olfactory cues of food can lead to changes in physiological responses and increase the likelihood and amount of food intake. However, no studies have explored the role of spicy food cues in cue reactivity among spicy food cravers. The exploratory study aimed to investigate cue-induced physiological responses, subjective cravings, eating behaviors and their associations in spicy food cravers. A group of spicy cravers (n = 59) and a group of age- and sex-matched non-cravers (n = 60) were exposed to food cues that contained or did not contain chili, during which physiological responses and food consumption were measured. The results revealed that spicy food cravers showed increased salivation and heart rate in response to food cues that contained chili compared to cues without chili and consumed significantly more chili oil after chili exposure. For cravers, heart rate during chili exposure was positively correlated with changes in subjective spicy food craving, and increases in subjective spicy food craving during chili exposure positively predicted subsequent chili oil consumption. The current exploratory study confirms the 'cued overeating' model and extends previous findings on food cravings, showing that even though chili peppers can elicit aversive oral burns and pain, they share the same physiological mechanism underlying cue reactivity as other kinds of cravings.

The effect of alcohol on food-related attentional bias, food reward and intake: Two experimental studies

Acute alcohol consumption has been shown to increase food intake, and long-term alcohol consumption may be a risk for weight gain. A potential, but under-studied, mechanism for this effect is alcohol's ability to enhance food reward. In two studies, participants consumed an alcoholic drink (Study 1: 0.3 grams of alcohol per kilogram of bodyweight (g/kg); Study 2: 0.6 g/kg) and a placebo-alcohol drink in a within-subjects design. In both studies, food-related appetitive and motivational states, and attentional bias (AB) towards food-related cues were measured. In Study 1 (N = 44), participants completed a visual probe task with concurrent recording of eye-movements which measured AB towards images of palatable foods, unpalatable foods, and non-food control items. Participants also completed measures of appetite and snack urge ratings, salivary response towards palatable foods and an ad libitum food taste test. In Study 2 (N = 84), participants completed a similar procedure, but completed a modified Stroop task which measured differences in food-related and alcohol-related AB across the two drink conditions. In Study 1, there was no difference in food-related AB between drink conditions, and no differences in snack urge, appetite ratings, salivary response, or food intake. In contrast, Study 2 showed an alcohol-induced increase in AB towards food, but not alcohol. Snack urge, alcohol urge ratings and ad libitum food intake were also higher after alcohol consumption, relative to the placebo. Collectively, these findings suggest that alcohol can increase food reward and food intake, but these effects may only occur at a higher dose.

Binge eating, but not dietary restraint, moderates the association between unhealthy food marketing exposure and sugary food consumption

Restrained eaters, those who exercise dietary restraint and often experience dietary lapses, may be particularly susceptible to food marketing. Findings are mixed as to whether restrained eaters consume more food after exposure to unhealthy food marketing, and little is known about whether food marketing may have more impact on those who exercise successful dietary restraint as compared with those who experience dietary lapses, such as binge eating. In the current study, participants were 38 young women, ages 18-22 years old. Both dietary restraint and binge eating were measured by the Eating Disorder Examination-Questionnaire. Participants viewed both unhealthy food commercials and non-food commercials two separate times in the laboratory, and ad libitum candy intake was subsequently measured. Results indicated that participants who endorsed binge eating ate significantly more candy than those who did not endorse binge eating after they viewed unhealthy food commercials F (1, 35) = 20.49, p < .001, η2 = 0.37, but not after viewing non-food commercials. No significant differences in candy eaten emerged when comparing those who endorsed dietary restraint as compared to those who did not, regardless of commercial type. Findings demonstrate the importance of specific operational definitions of restrained eating to consider the differences between those who report binge eating, and those who do not. They also suggest that individuals who engage in binge eating may be particularly susceptible to overeating in response to unhealthy food marketing, marking a possible area for intervention.

Do restrained eaters show increased BMI, food craving and disinhibited eating? A comparison of the Restraint Scale and the Restrained Eating scale of the Dutch Eating Behaviour Questionnaire

Despite being used interchangeably, different measures of restrained eating have been associated with different dietary behaviours. These differences have impeded replicability across the restraint literature and have made it difficult for researchers to interpret results and use the most appropriate measure for their research. Across a total sample of 1731 participants, this study compared the Restraint Scale (RS), and its subscales, to the Dutch Eating Behaviour Questionnaire (DEBQ) across several traits related to overeating. The aim was to explore potential differences between these two questionnaires so that we could help to identify the most suitable measure as a prescreening tool for eating-related interventions. Results revealed that although the two measures are highly correlated with one another (rs = 0.73-0.79), the RS was more strongly associated with external (rs = -0.07 to 0.11 versus -0.18 to -0.01) and disinhibited eating (rs = 0.46 versus 0.31), food craving (rs = 0.12-0.27 versus 0.02-0.13 and 0.22 versus -0.06) and body mass index (rs = 0.25-0.34 versus -0.13 to 0.15). The results suggest that, compared to the DEBQ, the RS is a more appropriate measure for identifying individuals who struggle the most to control their food intake.

Neuroimaging, neuromodulation, and population health: the neuroscience of chronic disease prevention

Preventable chronic diseases are the leading cause of death in the majority of countries throughout the world, and this trend will continue for the foreseeable future. The potential to offset the social, economic, and personal burdens associated with such conditions depends on our ability to influence people's thought processes, decisions, and behaviors, all of which can be understood with reference to the brain itself. Within the health neuroscience framework, the brain can be viewed as a predictor, mediator, moderator, or outcome in relation to health-related phenomena. This review explores examples of each of these, with specific reference to the primary prevention (i.e., prevention of initial onset) of chronic diseases. Within the topic of primary prevention, we touch on several cross-cutting themes (persuasive communications, delay discounting of rewards, and self-control), and place a special focus on obesity as a disorder influenced by both eating behavior and exercise habits.

Conditioning of human salivary flow using a visual cue for sour candy

OBJECTIVE

Although the "mouthwatering" to sight, smell, or thought of food is commonly accepted in food and nutrition research, the concept of mouthwatering and human salivary flow conditioning is not well accepted in salivary research. The objective of this study was to revisit whether human salivary flow could be classically conditioned to a previously neutral stimulus.

DESIGN

Sour candy or a non-food control in opaque containers were presented to healthy participants (n = 8). Simple images were consistently paired with container contents. Participants viewed the images for 15 s, then opened the containers and ate (candy) or did not eat (non-food control) the contents. This was repeated 14 times (7 of each stimulus). Order was semi-randomized to ensure one candy and one non-food were presented as the first two and last two stimuli. Saliva was collected with cotton dental rolls during these presentations (first two and last two) after viewing the image for 15 s, but before opening the container.

RESULTS

Participants were successfully conditioned to increase salivary flow in response to the image that predicted candy, as demonstrated by greater weight of saliva in response to 1) the candy-paired image than the non-food-paired image, and 2) the candy-paired image at the end of the first visit compared with the beginning (when the image had no meaning). However, the effect was attenuated during the second visit.

CONCLUSIONS

We demonstrate classical conditioning of human salivary flow is achievable, but the effect may not persist to a second visit.

Compared to self-immersion, mindful attention reduces salivation and automatic food bias

Immersing ourselves in food images can sometimes make it feel subjectively real, as if the actual food were right in front of us. Excessive self-immersion into mental content, however, is a hallmark of psychological distress, and of several psychiatric conditions. Being aware that imagined events are not necessarily an accurate depiction of reality is a key feature of psychotherapeutic approaches akin to mindfulness-based interventions. Yet, it is still largely unknown to what extent one's engagement with mental content, considering it as real, biases one's automatic tendencies toward the world. In this study, we measured the change in subjective realism induced by a self-immersion and a mindful attention instruction, using self-reports and saliva volumes. Then, we measured behaviorally the impact of subjective realism changes on automatic approach bias toward attractive food (FAB) using an approach-avoidance task. We found a reduction in saliva volume, followed by a reduction in FAB in the mindful condition compared to the immersed condition. During the immersed condition only, saliva volumes, state and trait measures of subjective realism, and food craving traits were positively correlated with FAB values, whereas meditation experience was negatively correlated to it. We conclude that mindful attention instructions can de-automatize food bias.

Eating disorders need more experimental psychopathology

Eating disorders are severe and disabling mental disorders. The scientific study of eating disorders has expanded dramatically over the past few decades, and provided significant understanding of eating disorders and their treatments. Those significant advances notwithstanding, there is scant knowledge about key processes that are crucial to clinical improvement. The lack of understanding mechanisms that cause, maintain and change eating disorders, currently is the biggest problem facing the science of eating disorders. It hampers the development of really effective interventions that could be fine-tuned to target the mechanisms of change and, therefore, the development of more effective treatments. It is argued here that the science of eating disorders and eating disorder treatment could benefit tremendously from pure experimental studies into its mechanisms of change, that is, experimental psychopathology (EPP). To illustrate why eating disorders need more EPP research, some key symptoms - restriction of intake, binge eating and body overvaluation - will be discussed. EPP studies challenge some generally accepted views and offer a fresh new look at key symptoms. This will, consequently, better inform eating disorder treatments.

Construct validation of the Portuguese version of the Restraint Scale

Aim

The main purpose of this study was to adapt the Restraint Scale (RS) to Portuguese and examine its psychometric properties, specifically its construct validity.

Method

In this study, 238 normal-weight adults (82% women; Mean age = 36.6, SD = 15.0) participated in an online survey containing measures of Restraint Scale, Three Factor Eating Questionnaire, Dutch Eating Behaviour Questionnaire, and Body Dissatisfaction and Drive for Thinness scales.

Results

Exploratory factor analyses corroborated the two-factors structure found in previous studies, in particular when three items without clear factorial assignment and low correlation were excluded. A final two-factors version of the RS containing seven items presented a very good fit to the measurement model and good internal consistency. Confirmatory factor analysis of the 7-items RS in relation to a three-factor model of overeating, dieting and body dissatisfaction measures revealed that the RS was the only restraint measure loading in all three factors.

Conclusion

This suggests that the 7-items Portuguese version of the RS has good psychometric properties and unique features that lend it appropriate to identify and study unsuccessful chronic dieters.

Food Odours Direct Specific Appetite

Olfactory food cues were found to increase appetite for products similar in taste. We aimed to replicate this phenomenon for taste (sweet/savoury), determine whether it extends to energy density (high/low) as well, and uncover whether this effect is modulated by hunger state. Twenty-nine healthy-weight females smelled four odours differing in the energy density and taste they signalled, one non-food odour, and one odourless solution (control), in random order, for three minutes each. Appetite for 15 food products was rated in the following two minutes. Mixed model analyses revealed that exposure to an odour signalling a specific taste (respectively sweet, savoury) led to a greater appetite for congruent food products (sweet/savoury) compared to incongruent food products (savoury p < 0.001; sweet p < 0.001) or neutral food products (p = 0.02; p = 0.003). A similar pattern was present for the energy-density category (respectively high-energy dense, low-energy dense) signalled by the odours (low-energy products p < 0.001; high-energy products p = 0.008). Hunger state did not have a significant impact on sensory-specific appetite. These results suggest that exposure to food odours increases appetite for congruent products, in terms of both taste and energy density, irrespective of hunger state. We speculate that food odours steer towards intake of products with a congruent macronutrient composition.

Using virtual reality to study food cravings

Food cravings (FCs) are associated with overeating and obesity and are triggered by environmental cues. The study of FCs is challenged by difficulty replicating the natural environment in a laboratory. Virtual reality (VR) could be used to deliver naturalistic cues in a laboratory. The purpose of this study was to investigate whether food related cues delivered by VR could induce greater FCs than neutral VR cues, photographic food cues, or real food. Sixty normal weight non-dieting women were recruited; and, to prevent a floor effect, half were primed with a monotonous diet (MD). Experimental procedures involved delivering neutral cues via VR and food related cues via VR, photographs, and real food in counterbalanced order while measuring subjective (self-report) and objective (salivation) FCs. FCs produced by VR were marginally greater than a neutral cue, not significantly different from picture cues, and significantly less than real food. The modest effects may have been due to quality of the VR system and/or measures of FC (i.e., self-report and salivation). FC threshold among non-dieting normal weight women was lowered with the use of a MD condition. Weight loss programs with monotonous diets may inadvertently increase FCs making diet compliance more difficult.

The Rise and Fall of Self-Control

Environmental cues of temptation generally frustrate people’s long-term goal attainment. However, recent research suggests that temptation cues promote, rather than hamper long-term goal congruent effects in successful self-regulators. While previous work has started to shed light on the cognitive features of this rise and fall of self-control, the present research aims to significantly advance this study by exploring important implications for actual behavior in the domain of dieting. In combining a temptation cue exposure procedure with a concurrent schedules task, results of two studies demonstrated that tempting food cues increased unsuccessful, but not successful dieters’ effortful behavior toward high-calorie food. In contrast, tempting food cues increased successful dieters’ efforts toward low-calorie food, but did not affect unsuccessful dieters. The findings suggest that the behavior of both unsuccessful and successful dieters in response to tempting food cues is goal-directed rather than impulsive.

Goal Priming in Dieters: Recent Insights and Applications

What are the psychological mechanisms that make dieting so challenging in our food-rich living environment? Social psychological research on goal priming provides a useful framework for answering this question, as well as implications for how to enhance dieting success. This review presents and discusses recent research which shows that attractive food cues prime the hedonic eating goal in dieters, and thus facilitate overeating. However, external cues priming the goal of weight control can be used to offset these effects and thus to facilitate dieting success, as is demonstrated in both field and laboratory experiments. In addition, recent strategies to prevent hedonic effects of attractive food, such as mindful attention, can facilitate self-regulation. These recent advances in our understanding of dieting behavior have theoretical and practical implications for how successful dieting can be facilitated, both by means of individual strategies, as well as by environmental changes.

Mere exposure to palatable food cues reduces restrained eaters' physical effort to obtain healthy food

We examined whether exposure to cues of attractive food reduces effortful behavior toward healthy foods for restrained eaters. After manipulating food pre-exposure, we recorded handgrip force while presenting participants with pictures of healthy food objects. Because participants were led to expect that they could obtain each object (not specified beforehand) by squeezing the handgrip as forcefully as possible while the object was displayed on the screen, the recorded handgrip force constitutes a measure of spontaneous effortful behavior. Results show that restrained eaters, but not unrestrained eaters, displayed less forceful action toward healthy food objects (i.e., lower exertion of force) when pre-exposed to tempting food cues. No effects were found on palatability perceptions of the healthy foods. The results provide further insight into why restrained eaters have difficulties in maintaining a low-calorie diet in food-rich environments.

Food reinforcement and obesity. Psychological moderators

The relative reinforcing value of food (RRV(food)) provides an index of the motivation to eat. Research has shown that RRV(food) is higher in obese individuals than their non-obese peers, is associated with greater energy intake, predicts weight gain and interacts with impulsivity to predict energy intake. This study was designed to determine whether dietary restraint, dietary disinhibition or hunger moderate the effect of RRV(food) on the weight status and energy intake in 273 adults of various body mass index (BMI) levels. Hierarchical regression was used to assess the independent effects of RRV(food) on BMI and energy intake, controlling for age, sex, income, education, minority status, and RRV(reading). Results showed that greater RRV(food), but not RRV(reading), was associated with greater BMI and energy intake. Dietary disinhibition and dietary restraint moderated the relationship between RRV(food) and BMI, with dietary disinhibition being a stronger moderator of this relationship (r(2)=0.20) than dietary restraint (r(2)=0.095). In addition, dietary disinhibition moderated the effect of RRV(food) on energy intake. These results replicate the importance of RRV(food) as a predictor of obesity, and show that psychological factors moderate the effect of food reinforcement on body weight and energy intake. This trial was registered at clinicaltrials.gov as NCT00962117.

Effects of chewing gum on short-term appetite regulation in moderately restrained eaters

Orosensory stimulation is an important contributing factor to the development of satiation. Providing orosensory stimulation with few calories may satisfy appetite and help to suppress cravings for high energy snacks. This may be a useful strategy for those motivated to lose or maintain weight. The present study tested the hypothesis that chewing sweetened gum will reduce subjective appetite and subsequent snack intake in moderately restrained eaters. Within-subjects, repeated measures study, sixty healthy participants (53 women; body mass index, in kg/m(2): 26.2±4.5) came to the laboratory 4 times for a standard lunch. Immediately after this meal, participants rated hunger, appetite and cravings for sweet and salty snacks every hour until they returned to the laboratory 3 h later for snack. On two occasions during this 3 h period participants chewed gum for at least 15 min at hourly intervals (45 min) and on two occasions no gum was chewed. On two occasions salty snacks were offered and on two occasions sweet snacks were provided. A small but significant reduction in snack intake was observed, chewing gum reduced weight of snack consumed by 10% compared to no gum (p<0.05). Overall, chewing gum for at least 45 min significantly suppressed rated hunger, appetite and cravings for snacks and promoted fullness (p<0.05). This study demonstrated some benefit of chewing gum which could be of utility to those seeking an aid to appetite control.

The role of sensitivity to reward and impulsivity in food-cue reactivity

Exposure to the visual and olfactory characteristics of food can elicit a desire to eat and can stimulate food intake. This study sought to determine the extent to which sensitivity to reward and impulsivity are associated with this 'food-cue reactivity' in two motivational states (food deprived and non-food deprived). Female participants (N=120) were exposed to a pizza cue for three minutes whilst food deprived and non-food deprived. Before and after this period, three measures of food-cue reactivity were taken (ratings of desire to eat, craving, and desired portion size of the cued food). Two important findings emerged from the study. Firstly, individuals with higher levels of trait impulsivity experienced greater changes in appetite ratings in both motivational states (food deprived and non-food deprived). They also reported greater changes in desired portion size of a cued food when food deprived. Secondly, individuals with a high sensitivity to reward experienced a greater change in their desired portion of the cued food, but only when non-food deprived. These results indicate that individual differences in food-cue reactivity could be related to variation in sensitivity to stimuli that predict the occurrence of a reward, and to an inability to exercise sufficient self control in the presence of tempting environmental stimuli.

Who likes it more? Restrained eaters' implicit attitudes towards food

Previous work has been unclear as to how restrained eating is related to implicit attitudes towards food. The present paper introduces a new variant of the affective priming paradigm to measure implicit attitudes towards food among restrained and unrestrained eaters, using food pictures as primes and emoticons as targets. Results of two studies show that while unrestrained eaters evaluate palatable foods more positively than neutral and unpalatable foods, restrained eaters do not. In addition, it is shown that restrained eaters have stronger evaluations of the negative aspects of palatable food, and this influences their food attitudes. Thus, the present findings suggest that restrained eaters' chronic goal of dieting impacts their implicit attitude towards food items via their perception of the negative aspects of palatable food. These results are discussed with regard to the role of attitudes in the regulation of eating behavior.

Individual differences in food-cue reactivity. The role of BMI and everyday portion-size selections

This study sought to explore the association between sensitivity to food cues (sight and smell of food) and (i) body weight (overweight or non-overweight), (ii) typical everyday portion sizes, and (iii) the DEBQ-restraint scale. One hundred and twenty female participants (aged between 18 and 30) were exposed to the sight and smell of pizza for three minutes. Both before and after this period, three measures of food-cue reactivity were taken (ratings of desire to eat, craving, and a measure of desired portion size of the cued food). Separate regression analyses were used to explore the associations between the change in measures of cue reactivity from pre- to post-cue exposure, and (i) an overweight/non-overweight classification, (ii) a measure of participants everyday portion-size selection, and (iii) scores on the DEBQ-restraint scale. This analysis revealed that scores on the DEBQ-restraint scale were not significantly associated with changes in food-cue reactivity. However, individuals identified as overweight, and participants who reported consuming the largest everyday portion sizes, experienced a significantly greater change in their desired portion size of the cued food. The findings suggest that heightened food-cue reactivity might present an under-explored risk factor for overeating, and becoming overweight, and/or maintaining an overweight body shape.

How does food-cue exposure lead to larger meal sizes?

Exposure to the sight and smell of food influences our momentary desire to consume it. This study explored the process by which cue exposure promotes greater consumption of food. Three hypotheses were explored, cue exposure: (i) increases the planned consumption of food; (ii) increases tolerance of larger portion sizes; (iii) arrests the development of satiety. Female participants (n50) were each tested in two conditions. In a ‘cue condition’ they were exposed to the sight and smell of pizza for 60 s. Before and after this period they provided information about prospective and maximum tolerated portion sizes and their desire to eat pizza and other non-cued foods. Participants then consumed a fixed portion of pizza, rated their hunger and were finally offeredad libitumaccess to pizza. In the ‘no-cue condition’, cue exposure was replaced with a cognitive task. Cueing had little effect on tolerance of larger portion sizes or on hunger after consuming the fixed portion. Instead, it increased prospective pizza portion size and subsequent intake of pizza. Together, these results suggest that cueing increases the amount of food that people actively plan to eat. This plan is then executed, leading to greater intake. Pizza cueing also increased prospective portion size of other foods. Thus, contrary to previous reports, effects of exposure may generalise to other foods. Finally, we found evidence that restrained eaters are less ‘cue reactive’ than unrestrained eaters. In future, our approach might be adapted to consider whether heightened ‘cue reactivity’ represents a risk factor for obesity.

Healthy Cognition: Processes of Self-Regulatory Success in Restrained Eating

Two studies examined self-regulatory success in dieting. Previous research has indicated that restrained eaters (i.e., chronic dieters) might fail in their attempts at weight control because the perception of attractive food cues triggers hedonic thoughts about food and inhibits their dieting goal. However, recent work suggests that in some dieters, temptation cues activate the relevant goal and thus facilitate self-regulation. The present work extends these findings by showing that self-regulatory success moderates the effect of food cues on restrained eaters such that food cues activate the dieting goal in successful restrained eaters and inhibit the dieting goal in unsuccessful restrained eaters. The specific time course of these effects was examined. Moreover, a correlational study revealed that only successful restrained eaters translate their dieting intentions into action. Results are discussed in the context of nonconscious self-regulation and the role of automatic processes in the link between intention and behavior.

Novel calcium-gelled, alginate-pectin beverage reduced energy intake in nondieting overweight and obese women: interactions with dietary restraint status

BACKGROUND

Foods containing strong-gelling fibers may provide a safe and efficacious strategy for reducing food intake by stimulating endogenous satiety signaling.

OBJECTIVE

A novel, 2-part beverage, consisting of alginate-pectin and calcium components, that forms a stable, fibrous gel in the stomach was tested to determine its effects on subjective satiety and food intake in overweight and obese women.

DESIGN

The investigation was a within-subjects, double-blind, placebo-controlled study. Subjects (n = 29) ingested a 2-part beverage twice per day (once before breakfast and once midafternoon) for 7 d. Three alginate-pectin formulations were tested: 1.0 g, 2.8 g, and control (no fiber). Subjective satiety and ad libitum food intake were measured on days 1 and 7 of each 1-wk treatment period with a 1-wk washout between testings.

RESULTS

A significant reduction in food intake was observed at dinner for both formulations compared with the control formulation. The effects of the gel beverage differed as a function of rigid dietary restraint status. Women in the lower 50th percentile of rigid restraint consumed 12% less energy during the day and 22% less for the evening snack in the 2.8-g condition compared with the control condition. No effect was found for women in the upper 50th percentile of rigid restraint.

CONCLUSIONS

Consumption of a postingestion, calcium-gelled fiber beverage twice daily reduced energy intake in overweight and obese women with low rigid restraint scores. Use of foods designed to enhance satiety may be an effective adjunctive therapy for weight loss; however, more research is needed to determine how dietary restraint alters this response.