Eating for pleasure or just wanting to eat? Reconsidering sensory hedonic responses as a driver of obesity

Does sweetness exposure drive 'sweet tooth'?

It is widely believed that exposure to sweetened foods and beverages stimulates the liking and desire for sweetness. Here we provide an updated review of the empirical evidence from human research examining whether exposure to sweet foods or beverages influences subsequent general liking for sweetness (‘sweet tooth’), based on the conclusions of existing systematic reviews and more recent research identified from a structured search of literature. Prior reviews have concluded that the evidence for a relationship between sweet taste exposure and measures of sweet taste liking is equivocal, and more recent primary research generally does not support the view that exposure drives increased liking for sweetness, in adults or children. In intervention trials using a range of designs, acute exposure to sweetness usually has the opposite effect (reducing subsequent liking and desire for sweet taste), while sustained exposures have no significant effects or inconsistent effects. Recent longitudinal observational studies in infants and children also report no significant associations between exposures to sweet foods and beverages with measures of sweet taste preferences. Overall, while it is widely assumed that exposure to sweetness stimulates a greater liking and desire for sweetness, this is not borne out by the balance of empirical evidence. While new research may provide a more robust evidence base, there are also a number of methodological, biological and behavioural considerations that may underpin the apparent absence of a positive relationship between sweetness exposure and liking.

Dynamics of self-control during choice and post-choice consumption quantity

Observed choices between options representing a relative vice and a relative virtue have commonly been used as a measure of eating self-control in the literature. However, even though self-control operations may manifest across the post-choice consumption stage, either similarly or in different ways from the choice stage, most prior research has ignored consumption quantity of the chosen option. While the behavior of choosing a virtue instead of a vice does manifest self-control, we examine how this plays out in post-choice consumption. Specifically, we find that when processing resources are limited, after having chosen a virtue food, unrestrained eaters ironically consumed greater quantities and therefore more calories than restrained eaters (Study 1). This reflects more persistent self-control in the post-choice consumption stage among restrained eaters than unrestrained eaters, and occurs because choosing a virtue lowers accessibility of the self-control goal among unrestrained eaters relative to restrained eaters (Study 2), thereby increasing intake of the virtuous food. In contrast, subsequent to having chosen a vice, unrestrained eaters and restrained eaters did not show any such difference in intake (Study 1) or goal accessibility (Study 2). Together, these results reveal that persistence of self-control in the post-choice consumption stage depends on individuals' dietary restraint and their initial exercise of self-control in the choice decision. The mere act of choosing a virtue satisfies unrestrained eaters' self-control goal and leads to increased food intake, whereas the same act keeps the same goal activated among restrained eaters who reduce intake of the chosen virtue. Put differently, persistent self-control across choice and quantity decisions is observed only when those with a dietary goal show successful self-control enactment in the choice stage. We therefore highlight that the operation of self-control can be dynamic within a consumption episode, and thus, choice and post-choice quantity are both informative of self-control.

Medium-chain triglyceride-specific appetite is regulated by the β-oxidation of medium-chain fatty acids in the liver

Most studies on fat appetite have focused on long-chain triglycerides (LCTs) due to their obesogenic properties. Medium-chain triglycerides (MCTs), conversely, exhibit antiobesogenic effects; however, the regulation of MCT intake remains elusive. Here, we demonstrate that mice can distinguish between MCTs and LCTs, and the specific appetite for MCTs is governed by hepatic β-oxidation. We generated liver-specific medium-chain acyl-CoA dehydrogenase (MCAD)-deficient (MCADL-/-) mice and analyzed their preference for MCT and LCT solutions using glyceryl trioctanoate (C8-TG), glyceryl tridecanoate (C10-TG), corn oil, and lard oil in two-bottle choice tests conducted over 8 days. In addition, we used lick microstructure analyses to evaluate the palatability and appetite for MCT and LCT solutions. Finally, we measured the expression levels of genes associated with fat ingestion (Galanin, Qrfp, and Nmu) in the hypothalamus 2 h after oral gavage of fat. Compared with control mice, MCADL-/- mice exhibited a significantly reduced preference for MCT solutions, with no alteration in the preference for LCTs. Lick analysis revealed that MCADL-/- mice displayed a significantly decreased appetite for MCT solutions only while the palatability of both MCT and LCT solutions remained unaffected. Hypothalamic Galanin expression in control mice was elevated by oral gavage of C8-TG but not by LCTs, and this response was abrogated in MCADL-/- mice. In summary, our data suggest that hepatic β-oxidation is required for MCT-specific appetite but not for LCT-specific appetite. The induction of hypothalamic galanin upon MCT ingestion, dependent on hepatic β-oxidation, could be involved in the regulation of MCT-specific appetite.NEW & NOTEWORTHY Whether and how medium-chain triglyceride (MCT) intake is regulated remains unknown. Here, we showed that mice can discriminate between MCTs and LCTs. Hepatic β-oxidation participates in MCT-specific appetite, and hypothalamic galanin may be one of the factors that regulate MCT intake. Because of the antiobesity effects of MCTs, studying MCT-specific appetite may help combat obesity by promoting the intake of MCTs instead of LCTs.

Switching diets after 6-months does not result in renewed weight loss: a secondary analysis of a 12-month crossover randomized trial

Weight change trajectory from diet and lifestyle interventions typically involves rapid weight loss followed by a weight plateau after approximately 6 months. Changing from one weight-loss diet to another at the time of the plateau could instigate renewed weight loss. Therefore, our secondary analysis aimed to assess trajectory of weight loss in a 12-month, randomized, cross-over study. Forty-two adults were randomized to eat a healthy low-fat or healthy low-carbohydrate diet for 6 months then switched to the opposite diet for an additional 6 months. Regardless of diet assignment, participants experienced rapid initial weight loss, which slowed between 3 to 6 months. After switching diets at 6 months, weight modestly decreased until 9 months, but at a rate slower than the initial 3 months and slower than the rate from 3 to 6 months. This suggests that the weight loss plateau typically seen at 6 months is physiological and cannot be overcome by simply switching to a different weight-loss diet.

Barriers and facilitators to implementation of healthy food and drink policies in public sector workplaces: a systematic literature review

CONTEXT

Many countries and institutions have adopted policies to promote healthier food and drink availability in various settings, including public sector workplaces.

OBJECTIVE

The objective of this review was to systematically synthesize evidence on barriers and facilitators to implementation of and compliance with healthy food and drink policies aimed at the general adult population in public sector workplaces.

DATA SOURCES

Nine scientific databases, 9 grey literature sources, and government websites in key English-speaking countries along with reference lists.

DATA EXTRACTION

All identified records (N = 8559) were assessed for eligibility. Studies reporting on barriers and facilitators were included irrespective of study design and methods used but were excluded if they were published before 2000 or in a non-English language.

DATA ANALYSIS

Forty-one studies were eligible for inclusion, mainly from Australia, the United States, and Canada. The most common workplace settings were healthcare facilities, sports and recreation centers, and government agencies. Interviews and surveys were the predominant methods of data collection. Methodological aspects were assessed with the Critical Appraisal Skills Program Qualitative Studies Checklist. Generally, there was poor reporting of data collection and analysis methods. Thematic synthesis identified 4 themes: (1) a ratified policy as the foundation of a successful implementation plan; (2) food providers' acceptance of implementation is rooted in positive stakeholder relationships, recognizing opportunities, and taking ownership; (3) creating customer demand for healthier options may relieve tension between policy objectives and business goals; and (4) food supply may limit the ability of food providers to implement the policy.

CONCLUSIONS

Findings suggest that although vendors encounter challenges, there are also factors that support healthy food and drink policy implementation in public sector workplaces. Understanding barriers and facilitators to successful policy implementation will significantly benefit stakeholders interested or engaging in healthy food and drink policy development and implementation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021246340.

Measuring Pleasure from Food-Validation of the Food Pleasure Scale by Multiple Techniques and Mixed Methods

The development of scales and questionnaires to assess pleasure perception has gained prominence, particularly for evaluating anhedonia in mental disorders. The Food Pleasure Scale is a comprehensive tool exclusively dedicated to measuring pleasure perception from food and food-related experiences. This study aimed to evaluate the face validity and consistency reliability of the Food Pleasure Scale using a mixed methods approach. Twenty-two participants completed the Food Pleasure Scale questionnaire and participated in in-depth interviews to understand their interpretation of the scale items. The interview data underwent thematic analysis, and the quantitative survey data was compared to the qualitative interview responses. Results indicated a high level of understanding of all items in the Food Pleasure Scale, confirming its face validity and applicability. The mixed methods approach supported the consistency reliability, showing consistency between quantitative measures and participants' explicit and implicit expressions of food pleasure. Furthermore, the study revealed a novel aspect related to food pleasure: the concept of "making an effort". Overall, this study highlights the comprehensibility, validity, and potential of the Food Pleasure Scale in consumer studies. It effectively captures the subjective experience of pleasure derived from food and food-related encounters, making it a valuable tool for further research in this domain.

Sensing the Snacking Experience: Bodily Sensations Linked to the Consumption of Healthy and Unhealthy Snack Foods-A Comparison between Body Mass Index Levels

The World Health Organisation (WHO) has highlighted the need for immediate action regarding the escalating global prevalence of overweight and obesity. Based on the need for long-term strategies supporting dietary behaviour changes, the concept of 'interoception' (i.e., sensing the body's internal state) has been proposed as promising for understanding and controlling food intake behaviours. As eating behaviours are motivated by the need for securing energy demands as well as the desire for pleasure, investigating the bodily sensations perceived in relation to food consumption can support our understanding of human food and eating behaviours. Here, a consumer study was conducted on 286 Danish consumers to explore the interoceptive experience of snack food consumption. This study included an investigation of the consumers' interoceptive capabilities and ability to feel pleasure, intuitive eating behaviours, snack food consumption frequency, the drivers of snack food consumption, food-related pleasure, and post-ingestive sensations linked to snack food consumption. The study was conducted on consumers with different Body Mass Index (BMI) levels to study potential differences between these groups. The study showed normal interoceptive capabilities and abilities to feel pleasure, with no differences between BMI groups. Regarding intuitive eating, the study found intuitive eating to be more prevalent among the group holding normal BMI. No significant differences between BMI groups were found in terms of snack intake frequency. However, differences between BMI groups were found in terms of: the drivers of snack consumption, the aspects bringing food-related pleasure from snack consumption, and the post-ingestive sensations felt after eating snack foods.

The influence of pediatric cancer treatment on taste perception and food hedonics: a systematic review

CONTEXT

Children with cancer are at risk of poor nutritional status during treatment and into survivorship. Objectively measured taste perception and self-reported food hedonics are 2 factors that may influence food intake.

OBJECTIVE

This 2-armed systematic review examined whether chemotherapy and radiotherapy affect (1) taste perception and (2) hedonic experiences of children and survivors of childhood cancer.

DATA SOURCE

A 2-armed systematic literature search was conducted in the Medline, CINAHL, Embase, and PsychInfo database until June 2022. The effects of cancer treatment on objective taste perception or food hedonics (ie, food liking or aversion and appetite) were examined.

DATA EXTRACTION

Peer-reviewed articles published in English of studies that included children (aged <18 years) or survivors of childhood cancer (any age) were reviewed. Risk of bias was determined using the Evidence Analysis Library by the Academy of Nutrition and Dietetics.

DATA ANALYSIS

A total of 1417 articles in the taste search arm and 3862 articles in the hedonics search arm were identified. Of these, 9 and 4 articles were eligible for review, respectively. Cancer treatment had highly variable effects on taste perception during treatment and into survivorship. Learned food aversions were experienced by children receiving chemotherapy treatment and liking of meats and salty foods by children with cancer was affected. The impact of treatment on appetite varied.

CONCLUSIONS

Cancer treatment did not uniformly affect taste perception. Food liking may be negatively affected, and learned food aversions may develop during cancer treatment. To establish the clinical relevance of childhood cancer treatment on taste perception and food hedonics, more research is required.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no.CRD42020207127.

Taste disturbance in patients with advanced cancer: a scoping review of clinical features and complications

PURPOSE

The purpose of this scoping review is to appraise the published literature on taste disturbance in patients with advanced cancer, with the specific objectives being to determine its prevalence, clinical features and complications.

METHODS

This scoping review was conducted using the recommended methodological framework. A detailed search of databases (Medline, Embase, CINAHL and PsycInfo) was conducted to identify eligible studies: eligible studies needed to include patients with advanced cancer and needed to include details of clinical features and/or complications of taste disturbance. Standard bibliographic/systematic review software was used to store the records and manage the review process, respectively.

RESULTS

Twenty-five studies were identified from the database searches. The studies identified included eight physical and/or psychological symptom studies, six symptom cluster studies, five oral symptom studies and six taste and/or smell specific studies. Detailed data is presented on the clinical features and complications of taste disturbance and on the symptom clusters involving taste disturbance in this cohort of patients.

CONCLUSION

This scoping review identified a relatively small number of relevant studies involving a relatively small number of participants. Nevertheless, it confirms that taste disturbance is a common problem in patients with advanced cancer and is associated with significant morbidity because of the primary condition and the associated complications.

Beyond ultra-processed: considering the future role of food processing in human health

Food-based dietary guidelines have been the basis of public health recommendations for over half a century, but more recently, there has been a trend to classify the health properties of food not by its nutrient composition, but by the degree to which it has been processed. This concept has been supported by many association studies, narrative reviews and the findings from one randomised controlled feeding trial, which demonstrated the sustained effect of ultra-processed diets on increasing both energy intake and body weight. This has led to widespread speculation as to specific features of ultra-processed foods that promote increased energy intakes. Rising interest in the ultra-processed topic has led to proposals to include guidance and restrictions on the consumption of processed foods in national dietary guidelines, with some countries encouraging consumers to avoid highly processed foods completely, and only choose minimally processed foods. However, there remains a lack of consensus on the role of processed foods in human health when faced with the challenges of securing the food supply for a growing global population, that is, healthy, affordable and sustainable. There has also been criticism of the subjective nature of definitions used to differentiate foods by their degree of processing, and there is currently a lack of empirical data to support a clear mechanism by which highly processed foods promote greater energy intakes. Recommendations to avoid all highly processed foods are potentially harmful if they remove affordable sources of nutrients and will be impractical for most when an estimated two-thirds of current energy purchased are from processed or ultra-processed foods. The current review highlights some considerations when interpreting the dietary association studies that link processed food intake to health and offers a critique on some of the mechanisms proposed to explain the link between ultra-processed food and poor health. Recent research suggests a combination of higher energy density and faster meal eating rates are likely to influence meal size and energy intakes from processed foods and offers new perspectives on how to manage this in the future. In going beyond the ultra-processed debate, the aim is to summarise some important considerations when interpreting existing data and identify the important gaps for future research on the role of processed food in health.

Testing for Protein Leverage in Patients with Gastric Bypass: A Pilot Study

INTRODUCTION

Protein leverage (PL) is the phenomenon whereby a dominant appetite for protein drives overconsumption of energy with a decline in the ratio of protein to fat and carbohydrate in the diet. PL has been independently verified in several randomized control trials, and its predictions are supported by diet surveillance data. Our aim in the present study was to test whether surgical intervention through gastric bypass will ameliorate the PL effect.

METHODS

Ten patients with gastric bypass (2-5 years postsurgical time) were given ad libitum access to study food comprising 10%, 15%, or 25% protein and no access to other foods for 3 days while controlling food palatability and variety. Food intake was measured, and energy and nutrient intakes were calculated. Body weight, blood chemistry, lipid profile, hormones (insulin, leptin, and ghrelin), and creatinine were determined before and after each experimental period.

RESULTS

The gastric bypass patients in our study did not show evidence for protein intake regulation as predicted under PL but ate to constant total energy intake on the 10%, 15%, and 25% protein diets with protein intake varying significantly. Patients lost weight in the three study periods, but significant weight loss was observed only on the 15% protein diet.

CONCLUSION

Our results suggest that gastric bypass might disengage the PL mechanism, thus ameliorating an appetite-specific mechanism that drives energy overconsumption in modern food environments.

Disentangling the role of NAc D1 and D2 cells in hedonic eating

Overeating is driven by both the hedonic component ('liking') of food, and the motivation ('wanting') to eat it. The nucleus accumbens (NAc) is a key brain center implicated in these processes, but how distinct NAc cell populations encode 'liking' and 'wanting' to shape overconsumption remains unclear. Here, we probed the roles of NAc D1 and D2 cells in these processes using cell-specific recording and optogenetic manipulation in diverse behavioral paradigms that disentangle reward traits of 'liking' and 'wanting' related to food choice and overeating in healthy mice. Medial NAc shell D2 cells encoded experience-dependent development of 'liking', while D1 cells encoded innate 'liking' during the first food taste. Optogenetic control confirmed causal links of D1 and D2 cells to these aspects of 'liking'. In relation to 'wanting', D1 and D2 cells encoded and promoted distinct aspects of food approach: D1 cells interpreted food cues while D2 cells also sustained food-visit-length that facilitates consumption. Finally, at the level of food choice, D1, but not D2, cell activity was sufficient to switch food preference, programming subsequent long-lasting overconsumption. By revealing complementary roles of D1 and D2 cells in consumption, these findings assign neural bases to 'liking' and 'wanting' in a unifying framework of D1 and D2 cell activity.

Discordance between assessments of food cue responsiveness: Implications for assessment in youth with overweight/obesity

Food cue responsiveness (FCR), broadly defined as behavioral, cognitive, emotional and/or physiological responses to external appetitive cues outside of physiological need, contributes to overeating and obesity among youth and adults. A variety of measures purportedly assess this construct, ranging from youth- or parent-report surveys to objective eating tasks. However, little research has assessed their convergence. It is especially important to evaluate this in children with overweight/obesity (OW/OB), as reliable and valid assessments of FCR are essential to better understand the role of this critical mechanism in behavioral interventions. The present study examined the relationship between five measures of FCR in a sample of 111 children with OW/OB (mean age = 10.6, mean BMI percentile = 96.4; 70% female; 68% white; 23% Latinx). Assessments included: objectively measured eating in the absence of hunger (EAH), parasympathetic activity when exposed to food, parent reported food responsiveness subscale from the Child Eating Behavior Questionnaire (CEBQ-FR), child self-reported Power of Food total score (C-PFS), and child self-reported Food Cravings Questionnaire total score (FCQ-T). Statistically significant spearman correlations were found between EAH and CEBQ-FR (ρ = 0.19, p < 0.05) and parasympathetic reactivity to food cues with both C-PFS (ρ = -0.32, p = 0.002) and FCQ-T (ρ = -0.34, p < 0.001). No other associations were statistically significant. These relationships remained significant in subsequent linear regression models controlling for child age and gender. The lack of concordance between measures assessing highly conceptually related constructs is of concern. Future studies should seek to elucidate a clear operationalization of FCR, examine the associations between FCR assessments in children and adolescents with a range of weight statuses, and evaluate how to best revise these measures to accurately reflect the latent construct being assessed.

Enhanced sweet taste perception in obesity: Joint analysis of gustatory data from multiple studies

Introduction

While sweet taste perception is a potential determinant of feeding behavior in obesity, the supporting evidence is inconsistent and is typically associated with methodological limitations. Notably, possible associations between sweet taste perception and measures of food reward remain undetermined.

Materials and methods

We conducted a cross-sectional analysis comparing 246 individuals with severe obesity and 174 healthy volunteers using a validated method for taste perception assessment. We included gustatory variables, namely intensity and pleasantness ratings of sour, salt, sweet, and bitter tastants, and taste thresholds assessed by electrogustometry. Reward-related feeding behavior, including hedonic hunger, food addiction, feeding behavior traits, and acceptance of foods and alcohol, was evaluated using self-rated scales for comparison with gustatory measures.

Result

In logistic regressions adjusted for age, gender, educational level, and research center, we found that a greater likelihood of belonging to the obesity group was associated with higher sweet intensity ratings (OR = 1.4, P = 0.01), hedonic hunger, food addiction symptoms, restrained and emotional eating (1.7 < OR ≤ 4.6, all P ≤ 0.001), and lower alcohol acceptance (OR = 0.6, P = 0.0002). Using principal component analysis, we found that while hedonic hunger, food addiction, and emotional eating were strongly interrelated, they were not associated with sweet intensity perception that, in turn, had a closer relationship with alcohol acceptance and restrained eating.

Conclusion

We found that individuals with obesity report higher sweet taste intensity ratings than healthy controls. Furthermore, while psychological measures of reward-related feeding behavior assess a common construct, sweet intensity perception may represent a different obesity-related dimension.

The Restrain Food Database: validation of an open-source database of foods that should be eaten more or less as part of a healthy diet

Studies of food-related behaviours often involve measuring responses to pictorial stimuli of foods. Creating these can be burdensome, requiring a significant commitment of time, and with sharing of images for future research constrained by legal copyright restrictions. The Restrain Food Database is an open-source database of 626 images of foods that are categorized as those people could eat more or less of as part of a healthy diet. This paper describes the database and details how to navigate it using our purpose-built R Shiny tool and a pre-registered online validation of a sample of images. A total of 2150 participants provided appetitive ratings, perceptions of nutritional content and ratings of image quality for images from the database. We found support for differences between Food Category on appetitive ratings which were also moderated by state hunger ratings. Findings relating to individual differences in appetite ratings as well as differences between BMI weight categories are also reported. Our findings validate the food categorization in the Restrain Food Database and provide descriptive information for individual images within this investigation. This database should ease the burden of selecting and creating appropriate images for future studies.

Why Being 'Stressed' Is 'Desserts' in Reverse-The Effect of Acute Psychosocial Stress on Food Pleasure and Food Choice

The link between acute stress, food pleasure and eating behavior in humans by employing measures of individual reward mechanisms has not been investigated as of yet. Having these insights is key to understanding why many people experience a change in eating behavior when experiencing stress. Thirty-five Danes (mean age 21.71 years) underwent a stress-inducing and relaxation-inducing task based on a randomized cross-over study design. Both tasks were combined with the Leeds Food Preference Questionnaire, to investigate the effect of stress on specific measures of food reward. Furthermore, participants chose a snack, as a covert measure of actual food choice. The study found no effect on explicit liking, explicit wanting or relative preference. For implicit wanting, an effect was detected on high-fat sweet foods, with increasing scores for the stress-induced condition. Moreover, 54% chose a different snack following the stress-inducing condition. Interestingly, 14% chose to change their snack choice to no snack at all. Results suggest acute psychosocial stress can increase cravings for highly palatable foods for some, while for others an experience of loss of appetite prevails. Overall, this study points to a further understanding of why consumers have issues with making healthy food choices, ultimately affecting public health too.

Predicting Food Intake from Food Reward and Biometric Responses to Food Cues in Adults with Normal Weight Using Machine Learning

BACKGROUND

Eating behaviors are determined by a complex interplay between behavioral and physiologic signaling occurring before, during, and after eating.

OBJECTIVES

The aim was to explore how selected behavioral and physiologic variables separately and grouped together predicted intake of 8 different foods.

METHODS

One hundred adults with normal weight performed a food preference task combined with biometric measurements (the Steno Biometric Food Preference Task) in the fasting state. The task measured food reward as well as biometric (eye tracking, electrodermal activity, and facial expressions) responses to images of foods varying in fat content and taste. Energy intake from an ad libitum buffet of the same 8 foods as assessed in the preference task was subsequently assessed. A mixed-effects random forest approach was applied to explore how individual and combined measures of food reward and biometric responses predicted energy intake of the 8 single foods. The performance of the different prediction models was compared with the predictions from a linear model including only an intercept (naïve model) using bootstrap cross-validation.

RESULTS

Participants had a median [IQR] intake of 369 kJ [126-472 kJ] per food. Combined or separate measures of food reward or biometric responses did not predict energy intake better than the naïve model.

CONCLUSIONS

We did not find that the reward or biometric responses to food cues assessed in a clinical setting were useful in predicting energy intake of single foods. However, this study provides a framework in the field of behavioral nutrition for applying machine learning with a focus on individual predictions. This is necessary on the road toward personalized nutrition and provides great potential for handling complex data with multiple variables.This trial was registered at clinicaltrials.gov as NCT03986619.

Development of the Hedonic Overeating–Questionnaire (HEDO–Q)

Addictive-like eating is prevalent, but a clear conceptualization and operationalization outside of an addiction framework is lacking. By adopting a biopsychological framework of food reward, this study sought to develop and evaluate a brief self-report questionnaire for the trait assessment of hedonic overeating and dyscontrol. Items in the Hedonic Overeating–Questionnaire (HEDO–Q) were constructed following a rational approach and psychometrically evaluated in a large random sample from the German population (N = 2531). A confirmatory factor analysis supported the unidimensional nature of the six-item HEDO–Q with the three postulated components of wanting, liking, and dyscontrol. Psychometric properties were favorable with good corrected item-total correlations, acceptable item difficulty and homogeneity, and high internal consistency. Population norms were provided. The HEDO–Q revealed strict measurement invariance for sex and partial invariance for age and weight status. Discriminant validity was demonstrated in distinguishing participants with versus without eating disturbances or obesity. Associations with the established measures of eating disorder and general psychopathology supported the convergent and divergent validity of the HEDO–Q. This first evaluation indicates good psychometric properties of the HEDO–Q in the general population. Future validation work is warranted on the HEDO–Q’s stability, sensitivity to change, and predictive and construct validity.

The sound of silence: Presence and absence of sound affects meal duration and hedonic eating experience

The interplay between external auditory cues in the eating environment and cognitive processes, such as distraction, may influence food intake, but how and the degree to which they do is unclear. We report an experiment designed to investigate the effects of different sonic atmospheres on meal duration, food intake and evaluations, and responses to the sonic eating environment. In a quasi-naturalistic cafeteria setting, participants (N = 248) were eating a lunch meal whilst being in one of four conditions: slow music, fast music, cafeteria noise, and silence. The results revealed that participants eating their lunch while exposed to some kind of background sound spent more time on their meal than those eating in silence. In terms of music tempo, slow music prolonged meal duration compared to fast music, but did not lead to increased intake. The appropriateness and liking of the sonic atmosphere were positively correlated with the overall pleasantness of the eating experience and liking of the food. The findings provide support for existing evidence documenting the importance of ambient sound in relation to food experiences and provide further insights into how individuals perceive and respond to sonic meal environments. Results are discussed in terms of recommendations for future design of eating environments in different contexts.

Gut microbes participate in food preference alterations during obesity

Hypothalamic regulations of food intake are altered during obesity. The dopaminergic mesocorticolimbic system, responsible for the hedonic response to food intake, is also affected. Gut microbes are other key players involved in obesity. Therefore, we investigated whether the gut microbiota plays a causal role in hedonic food intake alterations contributing to obesity. We transferred fecal material from lean or diet-induced obese mice into recipient mice and evaluated the hedonic food intake using a food preference test comparing the intake of control and palatable diets (HFHS, High-Fat High-Sucrose) in donor and recipient mice. Obese mice ate 58% less HFHS during the food preference test (p < 0.0001) than the lean donors, suggesting a dysregulation of the hedonic food intake during obesity. Strikingly, the reduction of the pleasure induced by eating during obesity was transferable through gut microbiota transplantation since obese gut microbiota recipient mice exhibited similar reduction in HFHS intake during the food preference test (40% reduction as compared to lean gut microbiota recipient mice, p < 0.01). This effect was associated with a consistent trend in modifications of dopaminergic markers expression in the striatum. We also pinpointed a highly positive correlation between HFHS intake and Parabacteroides (p < 0.0001), which could represent a potential actor involved in hedonic feeding probably through the gut-to-brain axis. We further demonstrated the key roles played by gut microbes in this paradigm since depletion of gut microbiota using broad-spectrum antibiotics also altered HFHS intake during food preference test in lean mice. In conclusion, we discovered that gut microbes regulate hedonic aspects of food intake. Our data demonstrate that gut microbiota modifications associated with obesity participate in dysregulations of the reward and hedonic components of the food intake. These data provide evidence that gut microbes could be an interesting therapeutic target to tackle hedonic disorders related to obesity.

The impact of environmental sounds on food reward

Wanting and liking are both components of food reward, but they manifest in fundamentally different neural substrates. While wanting denotes anticipatory and motivational behaviors, liking is associated with consummatory and hedonic experiences. These distinct constructs have also been quantitatively dissociated in behavioral paradigms. Indeed, internal, physiological, and interoceptive states affect the degree to which the food presented is valued. However, how contextual sensory cues might impact these appetitive and rewarding responses to food remains unexplored. In light of the increasing empirical focus on sound in food research, we investigated the influence of environmental soundscapes on explicit liking, explicit wanting, implicit wanting, choice frequency, and reaction time of healthy/unhealthy food using an online version of the Leeds Food Preference Questionnaire (LFPQ). Soft nature sounds and loud restaurant noises were employed to induce emotional relaxation and arousal respectively. One hundred and one healthy university students completed a repeated-measure design of the LFPQ; once with each soundscape playing in the background. Generalized linear mixed model analyses detected a significant interaction effect between soundscape and food type on choice frequency, yet the post hoc analyses did not reach significance. No interaction effects between soundscape and food type on wanting or liking were discovered. However, hypothesis-driven analyses found that nature sounds increased explicit liking of healthy (vs. unhealthy) foods, while no effect of soundscape on any wanting measures (explicit or implicit) were observed. Finally, exploratory analyses indicated that restaurant noise (vs. nature sound) induced faster response times for both healthy and unhealthy foods. The study exemplifies that in an online setting, contextual auditory manipulation of certain food reward measures and decision processes is feasible.

Sensory Specific Desires. The Role of Sensory Taste Exposure in Desire for Food with a Similar or Different Taste Profile

The present study investigated how the sensory taste profile of a meal altered the subjective desire, wanting and liking of foods with a sweet, salty, sour, bitter, fatty, and spicy sensory profile, respectively. Participants (n = 85) ate a meal with a pronounced sensory taste profile: (1) sweet, (2) salty, or (3) sweet and salty combined. Self-reports of appetite, pleasantness, and sensory specific desires (SSD) were evaluated over the course of the meal using VAS-scales. SSDs were further studied through alterations in liking and desire for food samples with the main sensory profile being sweet (peach), salty (pretzel), sour (green apple), bitter (dark chocolate), fatty (whipped cream), and spicy (chilli nut), respectively. Consumption of food with a pronounced sensory taste profile was found to suppress the desire for food with a similar sensory taste profile, while the desire for different sensory profiles were enhanced or not affected. Further, when exposed to two pronounced tastes within the same meal, suppression of sensory desires was not only specific for the exposure tastes but tended to go beyond the sensory exposure. The findings suggest that taste variation within a meal holds the potential to create more satisfying meals, which can hinder additional desires after a meal and thus, lower additional calorie intake.

Insight on Current Advances in Food Science and Technology for Feeding the World Population

While the world population is steadily increasing, the capacity of Earth to renew its resources is continuously declining. Consequently, the bioresources required for food production are diminishing and new approaches are needed to feed the current and future global population. In the last decades, scientists have developed novel strategies to reduce food loss and waste, improve food production, and find new ingredients, design and build new food structures, and introduce digitalization in the food system. In this work, we provide a general overview on circular economy, alternative technologies for food production such as cellular agriculture, and new sources of ingredients like microalgae, insects, and wood-derived fibers. We present a summary of the whole process of food design using creative problem-solving that fosters food innovation, and digitalization in the food sector such as artificial intelligence, augmented and virtual reality, and blockchain technology. Finally, we briefly discuss the effect of COVID-19 on the food system. This review has been written for a broad audience, covering a wide spectrum and giving insights on the most recent advances in the food science and technology area, presenting examples from both academic and industrial sides, in terms of concepts, technologies, and tools which will possibly help the world to achieve food security in the next 30 years.

Snacking on Almonds Lowers Glycaemia and Energy Intake Compared to a Popular High-Carbohydrate Snack Food: An Acute Randomised Crossover Study

Consuming nuts may have advantages over other snack foods for health and body-weight regulation. Suggested mechanisms include increased satiety and lower glycaemia. We used an acute randomised crossover trial to assess glycaemic and appetite responses to consuming two isocaloric snacks (providing 10% of participants’ total energy requirements or 1030 kJ (equivalent to 42.5 g almonds), whichever provided greater energy): raw almonds and sweet biscuits among 100 participants with available data (25 males and 75 females) following 106 being randomised. Two hours after consuming a standardised breakfast, participants consumed the snack food. Finger-prick blood samples measuring blood glucose and subjective appetite ratings using visual analogue scales were taken at baseline and at 15 or 30 min intervals after consumption. Two hours after snack consumption, an ad libitum lunch was offered to participants and consumption was recorded. Participants also recorded food intake for the remainder of the day. The mean area under the blood glucose response curve was statistically and practically significantly lower for almonds than biscuits (mean (95% CI) difference: 53 mmol/L.min (45, 61), p < 0.001). Only the composite appetite score at 90 min was higher in the almond treatment compared to the biscuit treatment (45.7 mm vs. 42.4 mm, p = 0.035 without adjustment for multiple comparisons). There was no evidence of differences between the snacks for all other appetite ratings or for energy intake at the ad libitum lunch. However, mean energy intakes following snack consumption were significantly lower, both statistically and in practical terms, for the almond treatment compared to the biscuit (mean (95% CI) diff: 638 kJ (44, 1233), p = 0.035). Replacing popular snacks with almonds may have advantages in terms of glycaemia and energy balance.

Food on the Move: The Impact of Implied Motion in Pictures on Food Perceptions through Anticipated Pleasure of Consumption

To tackle obesity, upgrading the image of healthy food is increasingly relevant. Rather than focusing on long-term benefits, an effective way to promote healthy food consumption through visual advertising is to increase its pleasure perception. We investigate whether implied motion, a popular trend in food pictures, affects food perceptions through anticipated consumption pleasure. Prior research shows that motion affects food perceptions, but these studies focused on limited food categories, using experiments with a single food stimulus, and mainly showing unhealthy food effects. Therefore, we aim to (1) replicate prior findings on the effects of food in motion on appeal, tastiness, healthiness, and freshness perceptions; (2) examine whether these effects differ for healthy and unhealthy food; and (3) investigate whether anticipated pleasure of consumption drives the effects of implied motion on food perceptions. Three between-subjects experiments (N = 626) reveal no evidence for the effectiveness of motion (vs. no motion) across a large variety of food products. We further show no differential effects for healthy versus unhealthy foods. Moreover, implied motion does not increase appeal or taste perceptions through anticipated pleasure. Considering the current replication crisis, these findings provide more nuanced insights into the effectiveness of motion in visual food advertising.

A review of effort-based decision-making in eating and weight disorders

Effort-based decision-making provides a framework to understand the mental computations estimating the amount of work ("effort") required to obtain a reward. The aim of the current review is to systematically synthesize the available literature on effort-based decision-making across the spectrum of eating and weight disorders. More specifically, the current review summarises the literature examining whether 1) individuals with eating disorders and overweight/obesity are willing to expend more effort for rewards compared to healthy controls, 2) if particular components of effort-based decision-making (i.e. risk, discounting) relate to specific binge eating conditions, and 3) how individual differences in effort and reward -processing measures relate to eating pathology and treatment measures. A total of 96 studies were included in our review, following PRISMA guidelines. The review suggests that individuals with binge eating behaviours 1) are more likely to expend greater effort for food rewards, but not monetary rewards, 2) demonstrate greater decision-making impairments under risk and uncertainty, 3) prefer sooner rather than delayed rewards for both food and money, and 4) demonstrate increased implicit 'wanting' for high fat sweet foods. Finally, individual differences in effort and reward -processing measures relating to eating pathology and treatment measures are also discussed.

A Systematic Review of Obesity and Binge Eating Associated Impairment of the Cognitive Inhibition System

Altered functioning of the inhibition system and the resulting higher impulsivity are known to play a major role in overeating. Considering the great impact of disinhibited eating behavior on obesity onset and maintenance, this systematic review of the literature aims at identifying to what extent the brain inhibitory networks are impaired in individuals with obesity. It also aims at examining whether the presence of binge eating disorder leads to similar although steeper neural deterioration. We identified 12 studies that specifically assessed impulsivity during neuroimaging. We found a significant alteration of neural circuits primarily involving the frontal and limbic regions. Functional activity results show BMI-dependent hypoactivity of frontal regions during cognitive inhibition and either increased or decreased patterns of activity in several other brain regions, according to their respective role in inhibition processes. The presence of binge eating disorder results in further aggravation of those neural alterations. Connectivity results mainly report strengthened connectivity patterns across frontal, parietal, and limbic networks. Neuroimaging studies suggest significant impairment of various neural circuits involved in inhibition processes in individuals with obesity. The elaboration of accurate therapeutic neurocognitive interventions, however, requires further investigations, for a deeper identification and understanding of obesity-related alterations of the inhibition brain system.

Hedonic Hunger Is Associated with Intake of Certain High-Fat Food Types and BMI in 20- to 40-Year-Old Adults

BACKGROUND

Hedonic hunger occurs in response to a desire to consume food for pleasure. The μ-opioid system regulates the hedonic impact of food and the opioid receptor mu 1 gene (OPRM1) polymorphism has been associated with fat intake.

OBJECTIVES

The aim of this study was to determine whether the intake of high-fat food is associated with hedonic hunger and the OPRM1 polymorphism and whether these variables are related to BMI.

METHODS

Participants were 20- to 40-y-old women and men enrolled in Poznań, Poland in 2016-2018. The frequency of consumption of high-fat food was measured using a validated application for mobile devices. Hedonic hunger was assessed with the use of the Power of Food Scale (PFS). PFS1, PFS2, and PFS3 scores were generated for food available, food present, and food tasted, respectively. Genotyping of rs1799971 in the OPRM1 gene was performed using TaqMan probes. The associations were analyzed using linear regression or logistic regression, as appropriate.

RESULTS

Hedonic hunger scores were not associated with total high-fat food intake. Total PFS was associated with snack intake (β: 0.16, P = 0.0066). PFS1 was positively associated with healthy high-fat food intake (β: 0.27, P = 0.0001) and PFS2 with sweet high-fat food and fast-food intake (β: 0.27, P = 0.0030). OPRM1 genotype and hedonic hunger interacted on fast-food intake (β: -0.17; P < 0.0154). Total PFS and PFS2 increased the chance of having a BMI ≥ 25 kg/m2 (OR: 1.43; 95% CI: 1.03, 2.01; P = 0.0335 and OR: 1.89; 95% CI: 1.37, 2.61; P = 0.0001, respectively), whereas PFS3 decreased it (OR: 0.61; 95% CI: 0.41, 0.87; P = 0.0082).

CONCLUSIONS

Hedonic hunger is associated with the intake of selected types of high-fat food, but not with its total intake, in people aged 20-40 y. Associations between hedonic hunger and fast-food intake can be modified by OPRM1 genotype. Hedonic hunger is associated with BMI.

Investigating salience strategies to counteract obesity

The investigation of the characteristics and attributes that make a brand prominent for shoppers is known as salience research. This line of study concentrates on influencing buying behaviors via the manipulation of shopping environments and food products. Such promotional strategies successfully attract massive food sales and therefore have been associated with changes in dietary patterns and the epidemic expansion of non-communicable diseases, like obesity. Marketers have empirically proven that global buying patterns are influenced by their salience strategies and techniques. However, despite the significance of such methods, empirical salience investigations have rarely been extended beyond their primary business focus to the field of health promotion. Therefore, this study is presenting a way of transferring the salience knowledge to the health promotion field in order to track dietary choices and possibly gain information to identify buying and eating behaviors connected to obesity. The salience literature from various disciplines permits to hypothesize that consumers are more likely to have unhealthy diets when food-choices and conditions are saliently manipulated. A quasi-experimental method (combining salience measures with Bayesian analysis) was used to test this proposition. The results support the hypothesis and endorse the introduced research tool. As predicted, data reflect the latest national overweight and obesity statistics and suggest that habitual unhealthy diets are more likely when salience strategies link food products to taste, social and emotional attributes. These preliminary findings encourage further investigation to enhance the method as a possible epidemiological tool.

Food Liking but Not Wanting Decreases after Controlled Intermittent or Continuous Energy Restriction to ≥5% Weight Loss in Women with Overweight/Obesity

Food reward (i.e., liking and wanting) has been shown to decrease after different types of weight management interventions. However, it is unknown whether specific dietary modalities (continuous (CER) vs. intermittent (IER) energy restriction) have differing effects on liking and implicit wanting after weight loss (WL) and whether these changes are sustained after 1-year of no-contact. Women with overweight or obesity (age 18–55 years) were randomly allocated to controlled-feeding CER (25% daily energy restriction) or IER (alternating ad libitum and 75% energy restriction days). Study visits were conducted at baseline, post-WL (to ≥5% WL within 12 weeks) and 1-year post-WL. The main outcomes were liking and implicit wanting for 4 categories of common food varying in fat and taste assessed by the Leeds Food Preference Questionnaire. Linear mixed models were conducted on the 30 participants achieving ≥5% WL and 15 returners. After an initial WL of −5.1 ± 0.2 kg, after 1-year 2.6 ± 0.5 kg were regained. Liking but not wanting decreased after WL. Food reward after 1-year did not differ from baseline, but the high loss to follow-up prevents generalization. IER and CER did not differ in their effects on food reward during WL or at 1-year follow-up.

Dietary interventions for obesity: clinical and mechanistic findings

Dietary modification is central to obesity treatment. Weight loss diets are available that include various permutations of energy restriction, macronutrients, foods, and dietary intake patterns. Caloric restriction is the common pathway for weight reduction, but different diets may induce weight loss by varied additional mechanisms, including by facilitating dietary adherence. This narrative Review of meta-analyses and select clinical trials found that lower-calorie diets, compared with higher-calorie regimens, reliably induced larger short-term (<6 months) weight losses, with deterioration of this benefit over the long term (>12 months). Few significant long-term differences in weight loss were observed for diets of varying macronutrient composition, although some regimens were found to have short-term advantages (e.g., low carbohydrate versus low fat). Progress in improving dietary adherence, which is critical to both short- and long-term weight loss, could result from greater efforts to identify behavioral and metabolic phenotypes among dieters.

Homeostasis and food craving in obesity: a functional MRI study

OBJECTIVES

Food intake in obesity has been found to be reward-based and less contingent on homeostatic needs. Accordingly, previous studies investigating neural processing of food cues observed aberrant processing in reward- and control-related brain regions in obesity. To further investigate the relation between homeostasis and food intake, this study investigated the influence of glucose metabolism on the neuronal response during the regulation of food craving in participants with obesity.

METHODS

Twenty-five normal-weight and 25 women with obesity were examined on two occasions after receiving either water or glucose directly into the stomach using a nasogastric tube. Participants were blinded to the type of infusion and were required to refrain from eating for 16 h before each visit. An event-related fMRI paradigm was used to investigate the effect of intestinal glucose load on the neuronal response during the regulation of food craving.

RESULTS

A 2 × 2 mixed-model ANOVA revealed that craving regulation was associated with increased activation in fronto-parietal regions in participants with obesity when compared to healthy controls. However, this effect was observed independently from homeostatic satiety. A regression analysis revealed that the reduction of food craving was related to increased activation in the lingual gyrus in individuals with obesity following the infusion of water.

CONCLUSIONS

In participants with obesity, the neuronal response during the regulation of food craving is associated with increased neural cognitive top-down control and increased visual food processing. Since this observation was independent from satiety status, our results indicate a reduced influence of homeostasis on neural processing during food craving in obesity. This study was registered on clinicaltrials.org: NCT03075371.

Can eating pleasure be a lever for healthy eating? A systematic scoping review of eating pleasure and its links with dietary behaviors and health

The aims of this review were to map and summarize data currently available about 1) key dimensions of eating pleasure; 2) associations of eating pleasure, and its key dimensions, with dietary and health outcomes and 3) the most promising intervention strategies using eating pleasure to promote healthy eating. Using the scoping review methodology, a comprehensive search of the peer-reviewed literature (Medline, PsycInfo, Embase, ERIC, Web of Science, CINAHL, ABI/Inform global and Sociology Abstract) and of the grey literature (ProQuest Dissertations & Theses and Google) was carried out by two independent reviewers. We included 119 of the 28,908 studies found. In total, 89 sub-dimensions of eating pleasure were grouped into 22 key dimensions. The most frequently found related to sensory experiences (in 50.9% of the documents), social experiences (42.7%), food characteristics besides sensory attributes (27.3%), food preparation process (19.1%), novelty (16.4%), variety (14.5%), mindful eating (13.6%), visceral eating (12.7%), place where food is consumed (11.8%) and memories associated with eating (10.9%). Forty-five studies, mostly cross-sectional (62.2%), have documented links between eating pleasure and dietary and/or health outcomes. Most studies (57.1%) reported favorable associations between eating pleasure and dietary outcomes. For health outcomes, results were less consistent. The links between eating pleasure and both dietary and health outcomes varied according to the dimensions of eating pleasure studied. Finally, results from 11 independent interventions suggested that strategies focusing on sensory experiences, cooking and/or sharing activities, mindful eating, and positive memories related to healthy food may be most promising. Thus, eating pleasure may be an ally in the promotion of healthy eating. However, systematically developed, evidence-based interventions are needed to better understand how eating pleasure may be a lever for healthy eating.

Reduction of cat voluntary feed intake in the short-term response to the sugar cane fibre supplementation

Obesity is a well-known syndrome of excessive body fat in cats (Felis catus) that affects the health, welfare and lifespan of animals. Consequently, different diet strategies aiming to reduce voluntary feed intake in cats have been studied. One of these consists in reducing energy intake based on reduction of feed intake. Several clinical studies have demonstrated that dietary fibre inclusion in food reduced efficiently voluntary feed intake (VFI) in dogs. However, little clinical data is available regarding the impact of dietary fibre inclusion on cat’s feeding behaviours and VFI. The aim of the current study was to test the performance of sugar cane fibre included at three different levels in extruded feline diets. The main purpose was to measure the impact of fibre inclusion on the cats’ VFI, while maintaining palatability. Four feline diets were formulated with different inclusion levels of sugar cane fibre expressed on an as fed basis (0% sugar cane fibre (control), 3.7% of sugar cane fibre (SF3.7), 5.5% of sugar cane fibre (SF5.5) and 7.3% sugar cane fibre (SF7.3)). The VFI and palatability were evaluated in two different methods: a new method using 79 cats, called ‘consumption kinetics’ based on the dynamic measure of cat’s daily consumptions in ad libitum conditions providing information about cat’s feeding pattern, and the standard palatability two-bowl (versus) test using more than 30 cats. All foods had identical palatability performance, regardless of sugar cane fibre inclusion level, while the VFI of products containing 5.5% and 7.3% sugar cane fibre decreased significantly compared to the control diet. The level of supplementation of sugar cane fibre was efficient to reduce felines VFI without impairing food palatability level, and may be a useful ingredient to add to feline diets to improve the success of the weight management programs.

Customer-perceived quality, innovation and tradition: some empirical evidence

Purpose

This study aims to explore how customer-perceived quality is affected by innovation in traditional products in the bread, bakery and pastry industry. The study assesses whether innovating traditional products is an effective strategy, especially in traditional industries.

Design/methodology/approach

This study followed a quantitative method of analysis. Data were gathered from a sample of 200 Italian bread consumers and analysed using a two-pronged correlation analysis, and two hypotheses were tested using Pearson’s correlation.

Findings

The results showed the negative relationship between customer-perceived quality and innovating traditional products in traditional industries embedded in closed contexts.

Research limitations/implications

The study has several academic implications. First, by focusing on the traditional food industry, the study contributes to the theory by answering the call for research in this field; second, the findings contribute to the embeddedness construct and, third, to the studies of customer-perceived quality and to the literature on innovation.

Practical implications

The findings are particularly interesting for entrepreneurs and consultants in traditional industries who make decisions on whether it is better to innovate or to remain anchored to tradition.

Originality/value

The present study clarifies the shadowy side of innovation in traditional industries, such as the bread, bakery and pastry industry, and it reveals how tradition plays a meaningful role in those sectors.

Food-based social comparisons influence liking and consumption

This study examined the effects of food-based social comparisons on hedonic ratings and consumption of a meal. Participants were randomly assigned to one of three experimental conditions in which they were led to believe that they got a worse meal, a better meal, or the same meal as another participant. They then tasted and rated their own meal. Subsequent liking and ad lib food consumption were measured. Participants who were told that another person got a better meal than they did (upward comparison) liked their meal less than if they were told that another person received either the same meal as they did or a worse meal (downward comparison). Similarly, participants who were in the upward comparison condition ate less food than if they were in the control or downward comparison conditions. Consumption was mediated by liking. The results suggest that being told that someone else is eating a meal that is higher or lower in hedonic value than one's own meal induces hedonic contrast and influences liking and consumption.

Insights to the neural response to food cues in class III compared with class I and II obese adults using a sample of endometrial cancer survivors seeking weight loss

Background

The rates of severe or Class III obesity (BMI ≥ 40.0 kg/m²) and endometrial cancer (EC) incidence and mortality have been increasing significantly in the United States. Adults with severe obesity are more likely to die and women with severe obesity have a higher risk of EC development and mortality than those with Class I/II obesity (BMI: 30–<40 kg/m²). However, no prior studies have evaluated the neural response to food cues by obesity severity/class in adults with or without cancer.

Methods

We conducted a functional magnetic resonance imaging visual food cue task in 85 obese Stage I EC survivors who were seeking weight loss in a lifestyle intervention at baseline. We evaluated the neural response to high-calorie vs. non-food images after an overnight fast (fasted state) and after eating a standardized meal (fed state), and grouped patients by obesity class (Class I/II: n = 38; Class III: n = 47).

Results

In the fasted state, we found increased activation in several regions including the dorsolateral prefrontal cortex (DLPFC) in Class III and Class I/II patients (whole brain cluster corrected (WBCC), p < 0.05), which was significantly higher in Class III vs. Class I/II (p < 0.05). We found decreased activation in the insula in the fasted state, which was significantly lower in Class I/II vs. Class III (p = 0.03). In the fed state, we found increased activation in the DLPFC in Class III and Class I/II (WBCC, p < 0.05). The increased activation in cognitive control/inhibition regions (DLPFC) is consistent with the summative literature; however, the decreased activation in taste information processing regions (insula) was unexpected.

Conclusions

Our results provide novel insights on food cue response between different classes of obesity and highlight the importance of targeting the DLPFC in weight loss interventions, particularly in severely obese patients. Additional studies examining food-related neural circuitry between different classes of obesity are needed.

The Impact of Physical Activity on Food Reward: Review and Conceptual Synthesis of Evidence from Observational, Acute, and Chronic Exercise Training Studies

PURPOSE OF REVIEW

This review brings together current evidence from observational, acute, and chronic exercise training studies to inform public debate on the impact of physical activity and exercise on food reward.

RECENT FINDINGS

Low levels of physical activity are associated with higher liking and wanting for high-energy food. Acute bouts of exercise tend to reduce behavioral indices of reward for high-energy food in inactive individuals. A dissociation in liking (increase) and wanting (decrease) may occur during chronic exercise training associated with loss of body fat. Habitual moderate-to-vigorous physical activity is associated with lower liking and wanting for high-fat food, and higher liking for low-fat food. Food reward does not counteract the benefit of increasing physical activity levels for obesity management. Exercise training appears to be accompanied by positive changes in food preferences in line with an overall improvement in appetite control.

No evidence for an association between obesity and milkshake liking

BACKGROUND

Prevailing models of obesity posit that hedonic signals override homeostatic mechanisms to promote overeating in today's food environment. What researchers mean by "hedonic" varies considerably, but most frequently refers to an aggregate of appetitive events including incentive salience, motivation, reinforcement, and perceived pleasantness. Here we define hedonic as orosensory pleasure experienced during eating and set out to test whether there is a relationship between adiposity and the perceived pleasure of a palatable and energy-dense milkshake.

METHODS

The perceived liking, wanting, and intensity of two palatable and energy-dense milkshakes were assessed using the Labeled Hedonic Scale (1), visual analog scale (VAS), and Generalized Labeled Magnitude Scale (2) in 110 individuals ranging in body mass index (BMI) from 19.3 to 52.1 kg/m². Waist circumference, waist-hip ratio, and percent body fat were also measured. Importantly, unlike the majority of prior studies, we attempted to standardize internal state by instructing participants to arrive to the laboratory neither hungry nor full and at least 1-h fasted. Data were analyzed with general linear and linear mixed effects models (GLMs). Hunger ratings were also examined prior to hedonic measurement and included as covariates in our analyses.

RESULTS

We identified a significant association between ratings of hunger and milkshake liking and wanting. By contrast, we found no evidence for a relationship between any measure of adiposity and ratings of milkshake liking, wanting, or intensity.

CONCLUSIONS

We conclude that adiposity is not associated with the pleasure experienced during consumption of our energy-dense and palatable milkshakes. Our results provide further evidence against the hypothesis that heightened hedonic signals drive weight gain.

Post-Ingestive Sensations Driving Post-Ingestive Food Pleasure: A Cross-Cultural Consumer Study Comparing Denmark and China

Culture is one of the main factors that influence food assessment. This cross-cultural research aimed to compare Chinese and Danish consumers in their post-ingestive drivers of Post-Ingestive Food Pleasure (PIFP). We define PIFP as a “subjective conscious sensation of pleasure and joy experienced after eating”. We conducted two in-country consumer studies in Denmark (n = 48) and in China (n = 53), measuring post-ingestive sensations and PIFP using visual analogue scale, for three hours following consumption of a breakfast meal. Key results revealed perceived Satisfaction, Mental, Overall and Physical wellbeing to be highly influential on PIFP in both countries. Moreover, Danish consumers perceived appetite-related sensations such as Satiety, Hunger, Desire-to-eat and In-need-of-food to be influential on PIFP, which was not the case in China. In China, more vitality-related sensations such as Energized, Relaxation and Concentration were found to be drivers of PIFP. These results suggest similarities but also distinct subtleties in the cultural constructs of PIFP in Denmark and in China. Focusing on Food Pleasure as a post-ingestive measure provides valuable output, deeper insights into what drives Food Pleasure, and, importantly, takes us beyond the processes only active during the actual eating event.

Food, Eating, and the Gastrointestinal Tract

Food ingestion induces a metered response of the digestive system. Initially, the upper digestive system reacts to process and extract meal substrates. Later, meal residues not absorbed in the small bowel, pass into the colon and activate the metabolism of resident microbiota. Food consumption also induces sensations that arise before ingestion (e.g., anticipatory reward), during ingestion (e.g., gustation), and most importantly, after the meal (i.e., the postprandial experience). The postprandial experience involves homeostatic sensations (satiety, fullness) with a hedonic dimension (digestive well-being, mood). The factors that determine the postprandial experience are poorly understood, despite their potential role in personalized diets and healthy eating habits. Current data suggest that the characteristics of the meal (amount, palatability, composition), the activity of the digestive system (suited processing), and the receptivity of the eater (influenced by multiple conditioning factors) may be important in this context.