Dissecting ultra-processed foods and drinks: Do they have a potential to impact the brain?

Ultra-processed foods and drinks (UPF) are formulation of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes. They usually have a low nutrient but high energy density, with a high content of saturated and trans fats, and added sugars. In addition, they have characteristic organoleptic properties, and usually contain sophisticated additives, including artificial sweeteners, to intensify their sensory qualities and imitate the appearance of minimally processed foods. In addition, recent research has warned about the presence of chemicals (e.g., bisphenol) and neo-formed contaminants in these products. UPF production and consumption growth have been spectacular in the last decades, being specially consumed in children and adolescents. UPF features have been associated with a range of adverse health effects such as overeating, the promotion of inflammatory and oxidative stress processes, gut dysbiosis, and metabolic dysfunction including problems in glucose regulation. The evidence that these UPF-related adverse health effects may have on the neural network implicated in eating behavior are discussed, including the potential impact on serotonergic and dopaminergic neurotransmission, brain integrity and function. We end this review by placing UPF in the context of current food environments, by suggesting that an increased exposure to these products through different channels, such as marketing, may contribute to the automatic recruitment of the brain regions associated with food consumption and choice, with a detrimental effect on inhibitory-related prefrontal cortices. While further research is essential, preliminary evidence point to UPF consumption as a potential detrimental factor for brain health and eating behavior.

The role of maternal BMI on brain food cue reactivity in children: a preliminary study

Children of overweight and obese parents have an increased risk of obesity. Little is known the neural mechanisms underlying this relationship, specifically the brain systems implicated in self-regulation of food intake. The primary goal here is to examine relationships between maternal body mass index (BMI) and brain responses to food cues in children. Seventy-six children (8.62 ± 1.02 years; 28 M,48F) were included in this study. Height and weight were assessed for children and their biological parents. Maternal height and weight before pregnancy were extracted from the Electronic Medical Records (EMR). BMI (kg/m²) or BMIz (age- and sex-specific BMI) were calculated. Children underwent a magnetic resonance imaging session where they viewed food and non-food images before and after glucose ingestion. The dorsolateral prefrontal cortex (dlPFC) and anterior cingulate cortex (ACC) food cue reactivity was the measurement of interest for region-of-interest (ROI) analyses. Whole-brain exploratory analysis was performed as well. Non-parametric methods were used for data analysis. ROI and whole brain analyses showed that maternal current BMI was inversely associated with child's ACC and dlPFC food cue reactivity after glucose ingestion, adjusting for age and sex. No significant relationships were found between paternal BMI and child's food cue reactivity. Child BMIz was negatively associated with the ACC food cue reactivity after glucose ingestion. Our results supported the role of maternal adiposity on child's responses to appetitive food cues in brain self-regulation circuitry, which may influence eating behavior and obesity risk in children.

Prefrontal Cortex and Amygdala Subregion Morphology Are Associated With Obesity and Dietary Self-control in Children and Adolescents

A prefrontal control system that is less mature than the limbic reward system in adolescence is thought to impede self-regulatory abilities, which could contribute to poor dietary choices and obesity. We, therefore, aimed to examine whether structural morphology of the prefrontal cortex (PFC; involved in cognitive control) and the amygdala (a key brain region for reward-related processing) are associated with dietary decisions and obesity in children and adolescents. Seventy-one individuals between the ages of 8-22 years (17.35 ± 4.76 years, 51% female, 56% were overweight or obese) participated in this study; each participant completed a computer-based food choice task and a T1- and T2-weighted structural brain scans. Two indices of obesity were assessed, including age- and sex-specific body mass index (BMIz) and waist-to-height ratio (WHtR). The behavioral task included rating 60 food stimuli for tastiness, healthiness, and liking. Based on each participant's self-ratings, 100 binary food choices were then made utilizing a computer mouse. Dietary "self-control" was calculated as the proportion of trials where the individual chose the healthier food item (vs. the tastier food item) over the total number of trials. Cortical thickness and amygdala subnuclei volumes were quantified using FreeSurfer 6.0 and CIT168 atlas, respectively. We found that WHtR was negatively associated with the thickness of bilateral superior frontal, left superior temporal, right insula, and right inferior temporal regions (p < 0.05, corrected for multiple comparisons). We also found WHtR to be positively associated with the volume of the central nucleus (CEN) region of the amygdala (p = 0.006), after adjusting for the hemisphere, age, sex, and intracranial volumes. A similar data pattern was observed when BMIz was used. Moreover, we found that across all participants, thinner right superior frontal cortex and larger left CEN volumes predicted lower dietary self-control. These results suggest that differential development of the PFC and amygdala relate to obesity and dietary self-control. Further longitudinal studies are merited to determine causal relationships among altered PFC to amygdala neural circuitry, dietary self-control, and obesity.

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.

Care vs Food as an Emotional Regulation Strategy in Elementary School Children: The Role of the Attachment Style

According to attachment theory, potentially threatening stimuli tend to activate the attachment system for the search of the protective figure. In secure attachments, the experience of responsive relationships increases the probability of resorting to available figures as a strategy for regulating emotions in stressful situations. The aim of the research was to verify whether, in conditions of mild threat, children's attachment styles affect the choice between caring relationships and food as a form of emotion regulation. We used a mixed experimental design to perform this research. Here, we presented children (N = 65; M_age= 9.4) with threatening and neutral images and, afterwards, asked them to select from images of caring relationship or images of food. The results indicate that securely and ambivalently attached but not avoidantly attached children under both the neutral and threatening image conditions chose the care pictures over the food pictures. Second, only the securely attached increased their choice of care over food images in the threatening condition, and third, this difference was significant when compared with the avoidant children. In conclusion, the results show that although in general the choice of care is primary with respect to food, children with insecure attachments differ from secure children between the two options of emotional regulation.

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.

Obesity, Appetite, and the Prefrontal Cortex

PURPOSE OF REVIEW

Obesity is a chronic illness and its prevalence is growing worldwide and numerous factors play a role in the regulation of food intake. The prefrontal cortex (PFC) is involved in high-order executive function, regulation of limbic reward regions, and the inhibition of impulsive behaviors. Understanding the role of the PFC in the control of appetite regulation may contribute to a greater understanding of the etiology of obesity and could improve weight loss outcomes.

RECENT FINDINGS

Neuroimaging studies have identified lower activation in the left dorsolateral PFC (DLPFC) in obese compared to lean individuals and others have focused on efforts to improve cognitive control in this area of the brain. The DLPFC is a critical brain area associated with appetitive control, food craving, and executive functioning, indicating a candidate target area for treatment. Further studies are needed to advance our understanding of the relationship between obesity, appetite, and the DLPFC and provide validation for the effectiveness of novel treatments in clinical populations.