Calorie information and dieting status modulate reward and control activation during the evaluation of food images

The neural model of front-of-package label processing

Front-of-package (FOP) labels have been adopted in many countries to battle the obesity pandemic and its serious health consequences by providing clearer and easier-to-understand nutrition and health information. The effectiveness of FOP labels has been generally confirmed, with some contextual and individual factors modifying their effectiveness. Existing theories (eg, the dual-process theory) and shifting priorities for self-control, provide some explanations for the FOP label effect. However, the cognitive and neural mechanisms underlying the processing of FOP labels remain unknown. Here, a new model, namely, the neural model of FOP label processing, has been proposed to fill this gap by providing an integrated account of FOP label processing while simultaneously considering multiple important situational and individual factors in the same framework. This neural model is built on the core eating network (ie, the ventral reward pathway and the dorsal control pathway) for food cue processing and actual food consumption. The new model explains how FOP labels may facilitate attention, influence the core eating network, and thus alter food choices. It also demonstrates how motivation may modify FOP label processing in 2 ways: affecting attention (the indirect way) and changing the process of evaluating the food (the direct way). It further explains how some contextual and individual factors (eg, ego depletion, time pressure, and health knowledge) influence the process. Thus, the neural model integrates evidence from behavioral, eye-tracking, and neuroimaging studies into a single, integrated account, deepening understanding of the cognitive and neural mechanisms of FOP label processing. This model might facilitate consensus on the most successful FOP label. Moreover, it could provide insights for consumers, food industries, and policy makers and encourage healthy eating behaviors.

Heightened sensitivity to high-calorie foods in children at risk for obesity: insights from behavior, neuroimaging, and genetics

Pediatric obesity is a major public health concern. Genetic susceptibility and increased availability of energy-dense food are known risk factors for obesity. However, the extent to which these factors jointly bias behavior and neural circuitry towards increased adiposity in children remains unclear. While undergoing fMRI, 108 children (ages 5-11y) performed a food-specific go/no-go task. Participants were instructed to either respond ("go") or inhibit responding ("no-go") to images of food or toys. Half of the runs depicted high-calorie foods (e.g., pizza) whereas the other half depicted low-calorie foods (e.g., salad). Children were also genotyped for a DNA polymorphism associated with energy intake and obesity (FTO rs9939609) to examine the influence of obesity risk on behavioral and brain responses to food. Participants demonstrated differences in behavioral sensitivity to high- and low-calorie food images depending on task demands. Participants were slower but more accurate at detecting high- (relative to low-) calorie foods when responding to a neutral stimulus (i.e., toys) and worse at detecting toys when responding to high-calorie foods. Inhibition failures were accompanied by salience network activity (anterior insula, dorsal anterior cingulate cortex), which was driven by false alarms to food images. Children at a greater genetic risk for obesity (dose-dependent model of the FTO genotype) demonstrated pronounced brain and behavioral relationships such that genetic risk was associated with heightened sensitivity to high-calorie food images and increased anterior insula activity. These findings suggest that high-calorie foods may be particularly salient to children at risk for developing eating habits that promote obesity.

Nutrition claims influence expectations about food attributes, attenuate activity in reward-associated brain regions during tasting, but do not impact pleasantness

INTRODUCTION

Nutrition claims are one of the most common tools used to improve food decisions. Previous research has shown that nutrition claims impact expectations; however, their effects on perceived pleasantness, valuation, and their neural correlates are not well understood. These claims may have both intended and unintended effects on food perception and valuation, which may compromise their effect on food decisions.

METHODS

We investigated the effects of nutrition claims on expectations, perceptions, and valuation of milk-mix drinks in a behavioral (n = 110) and an fMRI (n = 39) study. In the behavioral study, we assessed the effects of a "fat-reduced" and a "protein-rich" nutrition claim on expected and perceived food attributes of otherwise equal food products. In the fMRI study, we investigated the effect of a "protein-rich" claim on taste pleasantness perception and valuation, and on their neural correlates during tasting and swallowing.

RESULTS

We found that both nutrition claims increased expected and perceived healthiness and decreased expected but not perceived taste pleasantness. The "protein-rich" claim increased expected but not perceived satiating quality ratings, while the "fat-reduced" claim decreased both expected and perceived satiating quality ratings. In the absence vs. presence of the "protein-rich" claim, we observed an increased activity in a cluster extending to the left nucleus accumbens during tasting and an increased functional connectivity between this cluster and a cluster in right middle frontal gyrus during swallowing.

CONCLUSION

Altogether, we found that nutrition claims impacted expectations and attenuated reward-related responses during tasting but did not negatively affect perceived pleasantness. Our findings support highlighting the presence of nutrients with positive associations and exposure to foods with nutrition claims to increase their acceptance. Our study offers insights that may be valuable in designing and optimizing the use of nutrition claims.

Neural correlates of food labels on brand, nature, and nutrition: An fMRI meta-analysis

Eating is an essential act of our everyday life, and it involves complicated cognitive appraisal and gustatory evaluation. This study meta-analyzed the functional magnetic resonance imaging (fMRI) studies about food labels on brand, nature and nutrition. Web of Science Core Collection (WoS), Scopus, and PubMed were queried to identify human fMRI studies written in English and published in peer-reviewed journals and used taste or food related labels. Studies were excluded if they reported no results from taste/food related stimuli versus control, no task-based fMRI results, or no results from whole-brain analysis. Nineteen studies entered the analysis. Results for the meta-analysis on food nutrition revealed that the precuneus on the right hemisphere was significantly activated, a brain region related to internal mentation of self-consciousness and nutritional evaluation. Results for the overall analysis on all 19 studies, the analysis on food brand, and the analysis on food nature revealed no significant brain regions. Food nutrition labels were generally processed by brain regions related to internal mentation of self-consciousness and nutritional evaluation. However, the neural correlates of labels of food brand and food nature were inconsistent across studies. More future studies are needed to better understand the cognitive processing of different kinds of food labels in our brain.

"Maybe a little bit of guilt isn't so bad for the overall health of an individual": a mixed-methods exploration of young adults' experiences with calorie labelling

Background

Menu labelling, and more specifically calorie labelling, has been posited as an intervention to improve nutrition literacy and the healthfulness of consumers’ food purchases. However, there is some concern calorie labelling may unintentionally trigger or exacerbate disordered eating among vulnerable persons. The purpose of this research was to explore young adults’ experiences with labelling, with a focus on its implications for their relationships with food.

Methods

Individual semi-structured interviews were conducted with participants from a campus-based menu labelling study. Interview data were inductively coded using thematic analysis and supported by survey data assessing disordered eating, body esteem, and related constructs.

Results

The sample consisted of 13 participants (10 women, 3 men), most of whom perceived themselves as “about the right weight” (62%). Four key themes included: (1) participants’ support of and skepticism about labelling interventions, (2) the identification of knowledge and autonomy as mechanisms of labelling interventions, (3) the role of the individual’s and others’ relationships with food in experiences with labelling, and (4) disordered eating and dieting as lenses that shape experiences with interventions. Participants’ perceptions of and experiences with calorie labels were shaped by gender, body esteem, and disordered eating risk.

Conclusions

The results provide insight into the complexity of young adults’ interactions with labelling interventions and context for future research exploring the unintended consequences of public health nutrition interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13364-w.

The orbitofrontal cortex spontaneously encodes food health and contains more distinct representations for foods highest in tastiness

The human orbitofrontal cortex (OFC) has long been associated with food reward processing and is thought to represent modality-independent signals of value. Food tastiness and health are core attributes of many models of food choice and dietary self-control. Here we used functional neuroimaging to examine the neural representation of tastiness and health for a set of 28 food categories selected to be orthogonal with respect to both dimensions. Using representational similarity analysis, in conjunction with linear mixed-effects modeling, we demonstrate that the OFC spontaneously encodes food health, whereas tastiness was associated with greater neural dissimilarity. Subsequent analyses using model dissimilarity matrices that encode overall tastiness magnitude demonstrated that the neural representation of foods grows more distinct with increasing tastiness but not with increasing health. In a separate study, we use lexical analysis of natural language descriptions of food to show that food tastiness is associated with more elaborate descriptions of food. Together these data show not only that the OFC spontaneously encodes the dimensions of health and tastiness when viewing appetitive food cues, but also that the neural and cognitive representations of food categories that are the highest in tastiness are more refined than those lower in tastiness.

Fetal Programming by Methyl Donors Modulates Central Inflammation and Prevents Food Addiction-Like Behavior in Rats

Fetal programming by hypercaloric intake leads to food addiction-like behavior and brain pro-inflammatory gene expression in offspring. The role of methylome modulation during programming on central immune activation and addiction-like behavior has not been characterized. We employed a nutritional programming model exposing female Wistar rats to chow diet, cafeteria (CAF), or CAF-methyl donor’s diet from pre-pregnancy to weaning. Addiction-like behavior in offspring was characterized by the operant training response using Skinner boxes. Food intake in offspring was determined after fasting–refeeding schedule and subcutaneous injection of ghrelin. Genome-wide DNA methylation in the nucleus accumbens (NAc) shell was performed by fluorescence polarization, and brain immune activation was evaluated using real-time PCR for pro-inflammatory cytokines (IL-1β, TNF-1α, and IL-6). Molecular effects of methyl modulators [S-adenosylmethionine (SAM) or 5-azatidine (5-AZA)] on pro-inflammatory cytokine expression and phagocytosis were identified in the cultures of immortalized SIM-A9 microglia cells following palmitic acid (100 μM) or LPS (100 nM) stimulation for 6 or 24 h. Our results show that fetal programming by CAF exposure increases the number of offspring subjects and reinforcers under the operant training response schedule, which correlates with an increase in the NAc shell global methylation. Notably, methyl donor’s diet selectively decreases lever-pressing responses for reinforcers and unexpectedly decreases the NAc shell global methylation. Also, programmed offspring by CAF diet shows a selective IL-6 gene expression in the NAc shell, which is reverted to control values by methyl diet exposure. In vitro analysis identified that LPS and palmitic acid activate IL-1β, TNF-1α, and IL-6 gene expression, which is repressed by the methyl donor SAM. Finally, methylation actively represses phagocytosis activity of SIM-A9 microglia cells induced by LPS and palmitic acid stimulation. Our in vivo and in vitro data suggest that fetal programming by methyl donors actively decreases addiction-like behavior to palatable food in the offspring, which correlates with a decrease in NAc shell methylome, expression of pro-inflammatory cytokine genes, and activity of phagocytic microglia. These results support the role of fetal programming in brain methylome on immune activation and food addiction-like behavior in the offspring.

A Neurobiological Model of Alcohol Marketing Effects on Underage Drinking

OBJECTIVE

Although an association between exposure to alcohol advertising and underage drinking is well documented, the underlying neurobiological contributions to this association remain largely unexplored. From an epidemiological perspective, identifying the neurobiological plausibility of this exposure-outcome association is a crucial step toward establishing marketing as a contributor to youth drinking and informing public policy interventions to decrease this influence.

METHOD

We conducted a critical review of the literature on neurobiological risk factors and adolescent brain development, social influences on drinking, and neural contributions to reward sensitization and risk taking. By drawing from these separate areas of research, we propose a unified, neurobiological model of alcohol marketing effects on underage drinking.

RESULTS

We discuss and extend the literature to suggest that responses in prefrontal-reward circuitry help establish alcohol advertisements as reward-predictive cues that may reinforce consumption upon exposure. We focus on adolescence as a sensitive window of development during which youth are particularly susceptible to social and reward cues, which are defining characteristics of many alcohol advertisements. As a result, alcohol marketing may promote positive associations early in life that motivate social drinking, and corresponding neurobiological changes may contribute to later patterns of alcohol abuse.

CONCLUSIONS

The neurobiological model proposed here, which considers neurodevelopmental risk factors, social influences, and reward sensitization to alcohol cues, suggests that exposure to alcohol marketing could plausibly influence underage drinking by sensitizing prefrontal-reward circuitry.

Functional connectivity underlying hedonic response to food in female adolescents with atypical AN: the role of somatosensory and salience networks

Atypical anorexia nervosa (AN) usually occurs during adolescence. Patients are often in the normal-weight range at diagnosis; however, they often present with signs of medical complications and severe restraint over eating, body dissatisfaction, and low self-esteem. We investigated functional circuitry underlying the hedonic response in 28 female adolescent patients diagnosed with atypical AN and 33 healthy controls. Participants were shown images of food with high (HC) or low (LC) caloric content in alternating blocks during functional MRI. The HC > LC contrast was calculated. Based on the previous literature on full-threshold AN, we hypothesized that patients would exhibit increased connectivity in areas involved in sensory processing and bottom-up responses, coupled to increased connectivity from areas related to top-down inhibitory control, compared with controls. Patients showed increased connectivity in pathways related to multimodal somatosensory processing and memory retrieval. The connectivity was on the other hand decreased in patients in salience and attentional networks, and in a wide cerebello-occipital network. Our study was the first investigation of food-related neural response in atypical AN. Our findings support higher somatosensory processing in patients in response to HC food images compared with controls, however HC food was less efficient than LC food in engaging patients' bottom-up salient responses, and was not associated with connectivity increases in inhibitory control regions. These findings suggest that the psychopathological mechanisms underlying food restriction in atypical AN differ from full-threshold AN. Elucidating the mechanisms underlying the development and maintenance of eating behavior in atypical AN might help designing specific treatment strategies.

Recruitment of cognitive control regions during effortful self-control is associated with altered brain activity in control and reward systems in dieters during subsequent exposure to food commercials

Engaging in effortful self-control can sometimes impair people’s ability to resist subsequent temptations. Existing research has shown that when chronic dieters’ self-regulatory capacity is challenged by prior exertion of effort, they demonstrate disinhibited eating and altered patterns of brain activity when exposed to food cues. However, the relationship between brain activity during self-control exertion and subsequent food cue exposure remains unclear. In the present study, we investigated whether individual differences in recruitment of cognitive control regions during a difficult response inhibition task are associated with a failure to regulate neural responses to rewarding food cues in a subsequent task in a cohort of 27 female dieters. During self-control exertion, participants recruited regions commonly associated with inhibitory control, including dorsolateral prefrontal cortex (DLPFC). Those dieters with higher DLPFC activity during the initial self-control task showed an altered balance of food cue elicited activity in regions associated with reward and self-control, namely: greater reward-related activity and less recruitment of the frontoparietal control network. These findings suggest that some dieters may be more susceptible to the effects of self-control exertion than others and, whether due to limited capacity or changes in motivation, these dieters subsequently fail to engage control regions that may otherwise modulate activity associated with craving and reward.