Hedonic Hunger Is Related to Increased Neural and Perceptual Responses to Cues of Palatable Food and Motivation to Consume: Evidence from 3 Independent Investigations

Daily Dietary Protein Distribution Does Not Influence Changes in Body Composition During Weight Loss in Women of Reproductive Years with Overweight or Obesity: A Randomized Controlled Trial

BACKGROUND

Preservation of fat-free mass (FFM) during intentional weight loss is challenging yet important to maintain a resting metabolic rate. A balanced protein distribution of 25-30 g per meal improves 24-h muscle protein synthesis, which may promote FFM maintenance and greater reductions in fat mass (FM) during weight loss in women.

OBJECTIVES

We aimed to determine whether the daily dietary protein distribution pattern during energy restriction influences changes in body composition in women of reproductive age. We hypothesized that evenly distributing protein across meals compared with the usual intake pattern of consuming most of the protein at the dinner meal would be superior in preserving FFM while reducing FM during weight loss.

METHODS

Healthy women (n = 43) aged 20-44 y with a BMI of 28-45 kg/m2 completed a randomized parallel feeding study testing 2 patterns of daily protein intake (even distribution across all meals compared with a skewed distribution with most protein consumed at the evening meal). Participants completed an 8-wk controlled 20% energy restriction (all foods provided), followed by an 8-wk self-choice phase in which participants were asked to maintain a similar diet and dietary pattern when purchasing and consuming their own foods. Body composition was measured at baseline, week 8, and week 16. Data were analyzed using mixed models. Statistical significance was set at P < 0.05. Data are presented as differences in least squares means ± SE.

RESULTS

No significant main effects of group or group-by-time interactions were observed. All measures exhibited the main effect of time (P < 0.001). Overall, body weight, FFM, FM, and body fat percentage decreased 5.6 ± 0.4, 1.0 ± 0.2, 4.6 ± 0.4 kg, and 2.3 ± 0.2%, respectively, during this 16-wk study.

CONCLUSION

Daily dietary protein distribution at a fixed protein level does not appear to influence changes in body composition during weight loss in women of reproductive age.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED

NCT03202069 https://classic.

CLINICALTRIALS

gov/ct2/show/NCT03202069.

The relationship among disordered eating behavior, power of food scale and sensitization of the reinforcing value of food

INTRODUCTION

Disordered eating behaviors are a current public health concern since their progression can lead to the development of a full criteria eating disorder. Sensitization to repeated intake of high energy density (HED) foods is associated with excess weight gain over time, but less is known about relationships with assessments of disordered eating. Thus, this study aims to understand how disordered eating behaviors refunlate to the influence of the food environment and sensitization.

METHOD

163 adolescents - 50 % female and 13.2 mean age - were followed for 24 months. Sensitization was assessed by comparing the relative reinforcing value (RRV) of HED food at baseline and after two weeks of daily intake; sensitization was defined as RRV of food after repeated intake. Study participants also completed the EDE-Q, and Power of Food Scale (PFS). We conducted multivariate general linear models to examine these associations.

RESULTS

Sensitization status and PFS scores at baseline were positively associated with EDE-Q subscale scores cross-sectionally, but not longitudinally, at baseline and 24 months. We found that sensitization to HED food and higher susceptibility to food cues relates to increased disordered eating behaviors and both at baseline and at 24-months.

DISCUSSION

These findings suggest that sensitization to repeated HED food intake and the food environment might be a risk factor for later engagement in disordered eating behaviors. Future studies should address the temporal relationships among these factors and the role that social norms around body weight and weight stigma may play in the development of these behaviors.

Lateral hypothalamic proenkephalin neurons drive threat-induced overeating associated with a negative emotional state

Psychological stressors, like the nearby presence of a predator, can be strong enough to induce physiological/hormonal alterations, leading to appetite changes. However, little is known about how threats can alter feeding-related hypothalamic circuit functions. Here, we found that proenkephalin (Penk)-expressing lateral hypothalamic (LHPenk) neurons of mice exposed to predator scent stimulus (PSS) show sensitized responses to high-fat diet (HFD) eating, whereas silencing of the same neurons normalizes PSS-induced HFD overconsumption associated with a negative emotional state. Downregulation of endogenous enkephalin peptides in the LH is crucial for inhibiting the neuronal and behavioral changes developed after PSS exposure. Furthermore, elevated corticosterone after PSS contributes to enhance the reactivity of glucocorticoid receptor (GR)-containing LHPenk neurons to HFD, whereas pharmacological inhibition of GR in the LH suppresses PSS-induced maladaptive behavioral responses. We have thus identified the LHPenk neurons as a critical component in the threat-induced neuronal adaptation that leads to emotional overconsumption.

Relationship between hedonic hunger and subjectively assessed sleep quality and perceived stress among university students: A cross-sectional study

Purpose

This study examined the relationship between hedonic hunger (HH), sleep quality, and stress levels among university students in the United Arab Emirates and the Kingdom of Bahrain.

Methods

We used a cross-sectional design with participants (N = 565) recruited via convenience sampling. Data were collected with a self-administered, standardized, and validated online questionnaire. HH was assessed with the Palatable Eating Motives Scale (PEMS) and Power of Food Scale (PFS), sleep quality and sleep components were assessed with the Pittsburgh Sleep Quality Index (PSQI), stress was evaluated with the Perceived Stress Scale (PSS), and physical activity was examined with the International Physical Activity Questionnaire. Descriptive and analytical statistics were used to assess the relationship between HH and sleep quality and perceived stress.

Results

There were positive associations between total PSQI scores and total PEMS (β = 0.14, 95% confidence interval [CI]: 0.06-0.25, P = 0.001) and PFS (β = 0.21, 95% CI: 0.45-1.04, P < 0.001). The likelihood of poor sleep quality increased by 8% (odds ratio [OR] = 1.08, P = 0.020) and 43% (OR = 1.43, P < 0.001) for each one-unit increase in PEMS and PFS scores, respectively. We also found positive associations between PSS scores and total PEMS (β = 0.19, 95% CI: 0.26-0.63, P < 0.001) and PFS (β = 0.23, 95% CI: 1.04-2.22, P < 0.001) scores.

Conclusion

Reducing HH and stress levels may help to enhance sleep quality among university students. Conversely, improving sleep quality and reducing stress levels could improve HH in this population.

Assessing hedonic hunger among Chinese adults using the Power of Food Scale: Psychometric properties and cross-cultural invariance between China and the US

Hedonic hunger refers to food consumption for pleasure without biological energy deficits. The Power of Food Scale (PFS) is a well-developed self-report instrument assessing hedonic hunger. The present study aimed to translate and validate the PFS into simplified Chinese (C-PFS) and examine its psychometric properties among Chinese adults. A total of 773 participants (51.1 % men, M age = 24.98 years, SD = 6.10) were recruited in the present study from college and community populations. Consistent with the previous studies, confirmatory factor analysis showed that the C-PFS had three factors: food present, food available, and food tasted. In addition, a Cronbach's alpha of 0.92 and an ICC of 0.86 suggested that the C-PFS has good internal consistency and test-retest reliability. In terms of convergent validity, the scores of C-PFS correlated significantly with disordered eating symptomatology and loss of control over eating. Measurement invariance tests showed that the C-PFS was invariant across gender and sample source groups in the Chinese sample. In addition, a U.S. sample of 490 college students (26.6 % men, M age = 21.41 years, SD = 5.45) was used to test the measurement invariance across countries, and results suggested a partial invariance across college students from China and those from the U.S. In conclusion, the C-PFS can be a useful tool for measuring hedonic hunger among adults in China, and there may be cultural differences in the measurement of the PFS in college students across China and the U.S.

Motivation to consume palatable foods as a predictor of body image dissatisfaction: Using the Power of Food Scale in a Brazilian sample

The Power of Food Scale (PFS) is a questionnaire for self-assessing the motivation to consume palatable foods, especially in environments where food is abundant and constantly available. This study aimed to a) assess the factorial structure of the PFS in a Brazilian sample and b) examine the relationship between the power of food and body image dissatisfaction and BMI. The PFS and Body Shape Questionnaire (BSQ) were applied to a sample of 300 adults. Data were analysed using confirmatory factor analysis. Composite reliability (CR) was used to verify factor reliability. A partial least squares structural equation model was used to verify the effect of the PFS score on body image dissatisfaction. The PFS had an adequate factorial structure in this Brazilian sample, showing three well-defined factors: food available (CR = 0.91), food tasted (CR = 0.84), and food present (CR = 0.87). The BSQ showed one reliable factor (CR = 0.97). The power of the food aggregate factor significantly predicted body mass index (β = 0.16; p = .01) and body image dissatisfaction (β = 0.46; p < .001). The effect size was small for body mass index (f² = 0.02) and medium for body image dissatisfaction (f² = 0.26). The food present factor also had a slightly higher average among the three PFS factors. Women had higher PFS scores than men. Understanding the role that this motivation plays in physical and psychological outcomes such as body dissatisfaction can contribute to developing treatment strategies and support health professionals' performance in clinical settings.

Positive alcohol expectancy and resting-state functional connectivity of the insula in problem drinking

Positive alcohol expectancy (AE), a significant predictor of excessive alcohol consumption, is associated with heightened drinking motivation and reduced control. As the insula interacts with the limbic and prefrontal structures to integrate stimulus saliency, interoception, and cognitive control, the region may play a unique role in modulating AE. Here, we examined resting-state functional connectivity of the right and left insula in relation to AE in 180 adult drinkers. Whole-brain multiple regressions and path analysis were performed to delineate the inter-relationship between AE, insular connectivity, and drinking severity. We found that heightened AE was associated with diminished right insular connectivity with regions involved in negative emotion processing and self-control, including the amygdala, putamen, and ventromedial prefrontal cortex. In contrast, there was a positive relationship between AE and right insular connectivity with regions implicated in motivated responses to alcohol stimuli, including the superior parietal lobule, postcentral and superior frontal gyri. Path analysis showed that the two sets of right insular connectivity exhibited opposing associations with AE and that their net strength (i.e., "control minus motivation") was negatively correlated with AE and drinking severity. Analyses of the left insula seed, in contrast, did not yield regional connectivity in significant correlation with AE. These findings highlight the roles of right insula connectivity in motivational and regulatory processes that may differentially modulate drinking behavior. Recruitment of the motivational circuit and/or disengagement of the affective control circuit would be associated with heightened AE and heavier alcohol consumption.

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.

Reward-related neural correlates in adolescents with excess body weight

The functional and connectivity reward processing in adults with excessive body weight is well documented, though is relatively less researched during adolescence. Given that reward and inhibition may be highly malleable during adolescence, it is unknown how impulsive behaviors, potentially stemming from impaired inhibitory control and heightened sensitivity to rewarding cues, relate to increases in body weight in adolescents. Adolescents (N = 76; mean age = 14.10 years, SD = 1.92) with varied body mass index (BMI) performed a child-friendly monetary incentive delay task during functional magnetic resonance imaging, to study reward processing during the anticipation of rewards (cue) and reactions to feedback about rewards (feedback). Our results show that adolescents with greater BMI z-score show neural activation and ventral striatum connectivity alterations in networks implicated in reward, salience detection, and inhibitory control. These bottom-up reward and top-down inhibitory control networks, as well as interactions between these networks were prevalent during the anticipation period (when the cue is presented) as well as when receiving feedback about whether one has received a reward. Specifically, our results were mainly driven by failure to receive a reward in the feedback period, and the anticipation of a potential reward in the anticipation period. Overall, we provide evidence for heightened reward salience as well as inhibitory control deficits that, in combination, may contribute to the impulsive behaviors that lead to higher BMI in adolescents.

Supporting eating behaviour of community-dwelling older adults: co-design of an embodied conversational agent

In order to support community-dwelling older adults with healthy eating behaviours, Embodied Conversational Agents (ECAs) may be an effective and engaging medium. However, ECAs have not yet been found to be capable of engendering behaviour change, which is partly attributed to the absence of a match with users’ practices, needs and preferences. Hence, we describe a co-design process with older adults that informs both the content and the appearance of an ECA. Data was gathered through three consecutive iterations of co-design sessions with two groups of community-dwelling older adults in the Netherlands. Prior to the first session, participants completed a seven-day lifestyle diary. This study adds knowledge on the meaning of healthy eating, as well as on specific barriers to, and opportunities for, giving advice using an ECA in this target group. Furthermore, we translate this knowledge into general advice for designing an ECA in the context of health behaviour change, while reflecting on a co-design process with older adults.

Do ADHD-impulsivity and BMI have shared polygenic and neural correlates?

There is an extensive body of literature linking ADHD to overweight and obesity. Research indicates that impulsivity features of ADHD account for a degree of this overlap. The neural and polygenic correlates of this association have not been thoroughly examined. In participants of the IMAGEN study, we found that impulsivity symptoms and body mass index (BMI) were associated (r = 0.10, n = 874, p = 0.014 FWE corrected), as were their respective polygenic risk scores (PRS) (r = 0.17, n = 874, p = 6.5 × 10-6 FWE corrected). We then examined whether the phenotypes of impulsivity and BMI, and the PRS scores of ADHD and BMI, shared common associations with whole-brain grey matter and the Monetary Incentive Delay fMRI task, which associates with reward-related impulsivity. A sparse partial least squared analysis (sPLS) revealed a shared neural substrate that associated with both the phenotypes and PRS scores. In a last step, we conducted a bias corrected bootstrapped mediation analysis with the neural substrate score from the sPLS as the mediator. The ADHD PRS associated with impulsivity symptoms (b = 0.006, 90% CIs = 0.001, 0.019) and BMI (b = 0.009, 90% CIs = 0.001, 0.025) via the neuroimaging substrate. The BMI PRS associated with BMI (b = 0.014, 95% CIs = 0.003, 0.033) and impulsivity symptoms (b = 0.009, 90% CIs = 0.001, 0.025) via the neuroimaging substrate. A common neural substrate may (in part) underpin shared genetic liability for ADHD and BMI and the manifestation of their (observable) phenotypic association.

Longitudinal Prospective Association between Hedonic Hunger and Unhealthy Food and Drink Intake in Adolescents

Hedonic hunger (i.e., extreme responsiveness to food) has been associated with obesity and poor diet, but findings in the existing literature have primarily been cross-sectional. The current study examined hedonic hunger as a prospective predictor of the longitudinal trajectory of unhealthy food and drink intake across adolescence. Ninth grade students from Los Angeles area high schools (analyzed sample N = 3268) completed paper-and-pencil surveys across four annual waves; hedonic hunger was assessed at Wave 1, and unhealthy food and drink intake was assessed at Waves 1-4. Multilevel models showed a significant main effect of hedonic hunger and interactions between hedonic hunger and the linear and quadratic components of time. The association between hedonic hunger and unhealthy food and drink intake was strongest at Wave 1 and weakened over time, yet those with higher hedonic hunger reported greater unhealthy food and drink intake across the four years. Efforts to prevent and intervene upon hedonic hunger and its association with unhealthy food and drink intake during childhood and adolescence are warranted.

Pregnant Women Consume a Similar Proportion of Highly vs Minimally Processed Foods in the Absence of Hunger, Leading to Large Differences in Energy Intake

BACKGROUND

The eating in the absence of hunger (EAH) experimental paradigm measures intake of highly palatable, highly processed foods when sated. However, no studies have examined EAH in pregnant women.

OBJECTIVE

The objectives were to investigate whether EAH in pregnant women differs by level of food processing and to examine relationships of EAH with hedonic hunger, addictive-like eating, and impulsivity.

DESIGN

EAH was assessed in a counterbalanced crossover feeding substudy in which participants completed two free-access eating occasions following a standardized meal during their second pregnancy trimester. Hedonic hunger (Power of Food Scale), addictive-like eating (modified Yale Food Addiction Scale), and impulsivity (Barratt Impulsiveness Scale-15) were assessed by self-report during early pregnancy.

PARTICIPANTS AND SETTING

Data were collected from March 2015 through September 2016 from a subsample of participants (n = 46) enrolled at ≤12 weeks gestation in an observational, prospective cohort study (the Pregnancy Eating Attributes Study) in North Carolina.

INTERVENTION

Participants were presented with highly processed and minimally processed foods in two separate assessments.

MAIN OUTCOME MEASURES

Energy intake (EAH-kcal) and percent consumed (EAH-%) (calculated as 100 × [amount consumed (g) / amount served (g)]) was measured overall and separately for sweet and savory foods.

STATISTICAL ANALYSES PERFORMED

Linear mixed models estimated the effect of condition on EAH. Hedonic hunger, addictive-like eating, impulsivity and their interaction were examined separately.

RESULTS

EAH-% was similar across conditions (16.3% ± 1.1% highly processed vs 17.9% ± 1.2% minimally processed; P = 0.76), resulting in 338.5 ± 34.2 kcal greater energy intake in the highly processed vs minimally processed condition (P < 0.001). Hedonic hunger was not significantly associated with EAH; reward-related eating was positively associated with EAH-kcal and EAH-% of savory foods, and Barratt Impulsivity was positively associated with EAH-kcal and EAH-% overall, and with EAH-% of sweet foods (P < 0.05). There was little evidence of an interaction of Barratt Impulsivity with hedonic hunger or reward-related eating.

CONCLUSIONS

EAH in pregnant women occurs for both highly processed and minimally processed foods and correlates positively with self-reported addictive-like eating, but not hedonic hunger. Impulsivity did not modify associations of addictive-like eating with EAH in this sample.

Reward-related eating, self-regulation, and weight change in pregnancy and postpartum: the Pregnancy Eating Attributes Study (PEAS)

Background/Objectives.

Reward-related eating is hypothesized to underlie risk for weight gain in obesogenic environments, but its role is unknown during pregnancy and postpartum when weight change is normative, but excess weight gain and weight retention are common. This study examined associations of self-reported reward-related eating, self-regulation, and the home food environment with excessive gestational weight gain (GWG) and postpartum weight change.

Subjects/Methods.

Participants in the Pregnancy Eating Attributes Study observational cohort were enrolled at ≤12 weeks pregnancy and followed through one-year postpartum (458 recruited; 367 retained through delivery). Participants completed four measures of reward-related eating – Modified Yale Food Addiction Scale, Power of Food Scale, Multiple Choice Procedure, and a Reinforcing Value of Food Questionnaire; two measures of self-regulation – Barratt Impulsiveness Scale and Delay of Gratification Inventory; and a Home Food Inventory. Measured weight and skinfolds were obtained. Multinomial logistic and multiple linear regression analyses estimated associations of reward-related eating, self-regulation, and home food environment with excessive GWG, gestational fat gain, postpartum weight change, and percent of GWG retained.

Results.

Excessive GWG was associated with food reinforcement intensity, but not with any other measure of reward-related eating, self-regulation, or home food environment. Greater gestational fat gain was associated only with higher Multiple Choice Procedure. Postpartum weight change and percent of GWG retained were associated with greater Delay of Gratification and obesogenic home food environment, but not with any measure of reward-related eating or with impulsivity.

Conclusions.

Findings do not support the hypothesis that self-reported reward-related eating is associated with weight outcomes in pregnancy and postpartum but indicate a relation of Delay of Gratification with postpartum weight retention. Further research using both surveys and objective measures of reward-related eating is needed to advance our understanding of the relation of reward-related eating with weight changes during this critical period of a woman’s life.

The Power of Food: Self-control moderates the association of hedonic hunger with overeating, snacking frequency and palatable food intake

The purpose of the study was to explore whether self-control moderates the associations between hedonic hunger and overeating frequency, snacking frequency and palatable food intake. Data from the first wave of the Swiss Food Panel 2.0 study was analyzed (N = 4774), from the German- and French-speaking part of Switzerland (52% men). Measures included hedonic hunger assessed with the Power of Food Scale (PFS), the short form Self-Control Scale, overeating frequency, snacking frequency, intake of high-fat salty snack foods, and intake of high-sugar foods assessed with a semiquantitative food frequency questionnaire. Higher scores on the PFS and lower self-control capacities were correlated with higher intakes of both high-fat salty snack foods and high-sugar foods (referred to here as palatable foods), higher overeating frequency and higher snacking frequency. Four separate moderation analyses revealed that the positive associations of hedonic hunger with overeating frequency, snacking frequency and palatable food intake were significantly attenuated by self-control. Results of the present study indicate that people who are highly sensitive to the ready availability of palatable foods but also have high levels of self-control exhibit less frequent overeating and snacking, including less frequent intake of unhealthy palatable foods, than those low in self-control. Consequently, self-control may prevent overeating and thus may serve as a protective factor that decreases the risk of becoming overweight in individuals who are highly sensitive to the food environment.

Emotional disorder symptoms, anhedonia, and negative urgency as predictors of hedonic hunger in adolescents

Affect and reward are associated with unhealthy eating and weight; however, less research has examined affective predictors of hedonic hunger (i.e., extreme reward responsivity, pleasure toward, and drive for food), particularly among adolescents. Whether symptoms indicative of emotional disturbance increase risk of adverse reward-based eating-related symptoms such as hedonic hunger, is unknown. Such evidence could explain why emotional problems increase risk of eating and weight problems among adolescents, when eating-related health problems often originate. This report examined baseline emotional disorder symptoms, negative urgency (i.e., tendency to act impulsively in response to negative affect), and anhedonia (i.e., loss of interest in activities and decreased pleasure) as prospective predictors of increases in hedonic hunger in adolescents; associations between changes in emotional disturbance problems and hedonic hunger were also examined. Ninth-grade students (N = 2598) from high schools completed paper-and-pencil surveys at baseline and a 1-year follow-up. In a multivariable model controlling for the covariance of emotional problems, higher negative urgency, general anxiety, and obsessive-compulsive symptoms, and lower anhedonia at baseline independently predicted increases in hedonic hunger one year later. Also, increases in negative urgency, general anxiety, and obsessive-compulsive symptoms and decreases in anhedonia independently predicted increases in hedonic hunger. Affect- and reward-related variables may be important contributors to risk of hedonic hunger in adolescence.

Lack of prospective relationships of the Power of Food Scale with Body Mass Index and dieting over 2 years in U.S. emerging adults

BACKGROUND

This study investigated prospective relationships of the Power of Food Scale (PFS), a self-report measure of hedonic hunger, with weight outcomes and dieting in U.S. young adults.

METHODS

PFS (PFS-aggregate and subscales: PFS-available, PFS-present, PFS-tasted) was assessed in waves (W, years) 5 and 6 of a nationally representative cohort of 10th graders assessed annually (baseline n = 2785, 83% retention at W7). Internal consistency (Cronbach's α), 1-year stability (intraclass correlation coefficient, ICC) and confirmatory factor analysis (CFA) were examined. Analyses accounting for the complex survey design examined cross-sectional associations of W6 PFS with W6 BMI and dieting, and prospective relationships of PFS in each wave with BMI, 1-year BMI change (BMIΔ, W6-W5 and W7-W6), overweight/obesity onset (OWOB, moving to a higher risk weight category) and dieting in the following wave. Multiple imputations addressed missing data.

RESULTS

Baseline participant mean ± SE age was 20.3 ± 0.02 years. Mean BMI increased by approximately 0.6 kg/m² from W5 through W7; OWOB occurred in 7.4% of participants between W5-W6; 9.0% between W6-W7. Approximately half the sample reported dieting in each wave. W6 weight outcomes were not associated with W6 PFS, but W6 dieting frequency was positively associated with W6 PFS-available, PFS-present, and PFS-aggregate (but not PFS-tasted) in multivariable models. PFS was not prospectively associated with weight outcomes. Positive prospective associations of PFS with dieting frequency were inconsistent across waves and with respect to inclusion of covariates.

CONCLUSIONS

Greater PFS is associated with dieting cross-sectionally but was not a reliable indicator of susceptibility to future weight outcomes or dieting in young adults.

Uncontrolled eating: a unifying heritable trait linked with obesity, overeating, personality and the brain

Many eating-related psychological constructs have been proposed to explain obesity and overeating. However, these constructs, including food addiction, disinhibition, hedonic hunger, emotional eating, binge eating and the like all have similar definitions, emphasizing loss of control over intake. As questionnaires measuring the constructs correlate strongly (r > 0.5) with each other, we propose that these constructs should be reconsidered to be part of a single broad phenotype: uncontrolled eating. Such an approach enables reviewing and meta-analysing evidence obtained with each individual questionnaire. Here, we describe robust associations between uncontrolled eating, body mass index (BMI), food intake, personality traits and brain systems. Reviewing cross-sectional and longitudinal data, we show that uncontrolled eating is phenotypically and genetically intertwined with BMI and food intake. We also review evidence on how three psychological constructs are linked with uncontrolled eating: lower cognitive control, higher negative affect and a curvilinear association with reward sensitivity. Uncontrolled eating mediates all three constructs' associations with BMI and food intake. Finally, we review and meta-analyse brain systems possibly subserving uncontrolled eating: namely, (i) the dopamine mesolimbic circuit associated with reward sensitivity, (ii) frontal cognitive networks sustaining dietary self-control and (iii) the hypothalamus-pituitary-adrenal axis, amygdala and hippocampus supporting stress reactivity. While there are limits to the explanatory and predictive power of the uncontrolled eating phenotype, we conclude that treating different eating-related constructs as a single concept, uncontrolled eating, enables drawing robust conclusions on the relationship between food intake and BMI, psychological variables and brain structure and function.

Food addiction distinguishes an overweight phenotype that can be reversed by low calorie diet

Similarities in neural activation patterns in obese and substance-dependent subjects led to the food addiction concept, but studies exploiting this issue for obesity stratification are missing. We assessed brain activation in response to food cues using ¹⁸ F-2-fluoro-2-deoxy-glucose-PET in 36 overweight women, stratified by low or high food addiction groups according to the Yale Food Addiction Scale (YFAS). Assessments were repeated after a 3-month diet. We found greater activation in thalamus, hypothalamus, midbrain, putamen, and occipital cortex (reward), but not in prefrontal and orbitofrontal cortices (control/reward receipt) in the high-YFAS versus low-YFAS group. In high-YFAS subjects, orbitofrontal responsiveness was inversely related to YFAS severity and hunger rating, and positive associations were observed between regional brain activation and lipid intake. A 3-month diet abolished group differences in brain activation. Our data suggest that food addiction distinguishes an overweight phenotype that can be reversed by diet, opening to personalized strategies in obesity treatment.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

Can Mindfulness Address Maladaptive Eating Behaviors? Why Traditional Diet Plans Fail and How New Mechanistic Insights May Lead to Novel Interventions

Emotional and other maladaptive eating behaviors develop in response to a diversity of triggers, from psychological stress to the endless external cues in our modern food environment. While the standard approach to food- and weight-related concerns has been weight-loss through dietary restriction, these interventions have produced little long-term benefit, and may be counterproductive. A growing understanding of the behavioral and neurobiological mechanisms that underpin habit formation may explain why this approach has largely failed, and pave the way for a new generation of non-pharmacologic interventions. Here, we first review how modern food environments interact with human biology to promote reward-related eating through associative learning, i.e., operant conditioning. We also review how operant conditioning (positive and negative reinforcement) cultivates habit-based reward-related eating, and how current diet paradigms may not directly target such eating. Further, we describe how mindfulness training that targets reward-based learning may constitute an appropriate intervention to rewire the learning process around eating. We conclude with examples that illustrate how teaching patients to tap into and act on intrinsic (e.g., enjoying healthy eating, not overeating, and self-compassion) rather than extrinsic reward mechanisms (e.g., weighing oneself), is a promising new direction in improving individuals' relationship with food.

A narrative review of the construct of hedonic hunger and its measurement by the Power of Food Scale

INTRODUCTION

The term 'hedonic hunger' refers to one's preoccupation with and desire to consume foods for the purposes of pleasure and in the absence of physical hunger. The Power of Food Scale (PFS) was developed as a quantitative measure of this construct in 2009. Since then, over 50 published studies have used the PFS to predict appetite-related outcomes including neural, cognitive, behavioural, anthropometric and clinical measures.

OBJECTIVE

This narrative review evaluates how closely the PFS captures the construct it was originally presumed to assess and to more clearly define hedonic hunger itself.

METHODS

The measure's relationship to four domains is reviewed and summarized: motivation to consume palatable foods; level of actual consumption of such foods; body mass; and subjective loss-of-control over one's eating behaviour. Findings are synthesized to generate a more accurate understanding of what the PFS measures and how it may relate to the broader definition of hedonic hunger.

RESULTS

Results suggest that the PFS is closely related to motivation to consume palatable foods and, in extreme cases, occurrence of loss-of-control eating episodes. PFS scores are not consistently predictive of amount of food consumed or body mass.

CONCLUSIONS

Implications of these findings are discussed in the context of behavioural health, and avenues for further inquiry are identified.

Association between hedonic hunger and body-mass index versus obesity status

Obesity-associated differences in hedonic hunger, while consistently reported, have not been adequately quantified, with most studies failing to demonstrate strong correlations between Body Mass Index (BMI) and hedonic hunger indicators. Here, we quantified and assessed the nature of the relationship between hedonic hunger and BMI, in a cross-sectional study using the Portuguese version of the PFS (P-PFS) to measure hedonic hunger. Data were collected from 1266 participants belonging to non-clinical, clinical (candidates for weight-loss surgery) and population samples. Across samples, significant but weak positive associations were found between P-PFS scores and BMI, in adjusted linear regression models. However, in logistic regression models of data from the clinical and non-clinical samples, the P-PFS Food Available domain score was significantly and robustly associated with belonging to the clinical sample (OR = 1.8, 95%CI: 1.2–2.8; p = 0.008), while in the population sample it was associated to being obese (OR = 2.1, 95%CI: 1.6–2.7; p < 0.001). Thus, hedonic hunger levels are associated with obesity status with the odds of being obese approximately doubling for each unit increase in the P-PFS Food Available score.