A twin study of differences in the response of plasma ghrelin to a milkshake preload in restrained eaters

Disconnect between sympathetically-induced hunger suppression and consumption among highly restrained eaters following stress

Despite emphasis on findings suggesting restrained eaters increase food consumption under stress, unrestrained eaters' reduction in intake is more robust. Early proposals asserted unrestrained eaters significantly reduced intake after certain threats due to the hunger-inhibiting effects of autonomic influences, presuming unrestrained eaters are more responsive to these effects and restrained eaters rely less on physiological cues for eating. However, scant empirical evidence has substantiated these claims. This study examined whether a sequence exists whereby stress elicits autonomic activation, autonomic activation impacts hunger, and hunger then impacts eating, with dietary restraint altering the hunger-intake link. It was hypothesized that sympathetic nervous system activation would be greatest when ongoing safety from stress was uncertain, sympathetic activation would be linked to reduced hunger, and lower hunger would be associated with attenuated intake. Restraint, conceptualized via Hagan et al.'s (2017) latent restraint factors, was hypothesized to reduce the association between hunger and intake. Female participants (n = 147) were randomized to a stress + certain safety, stress + uncertain safety, or control condition. Sympathetic nervous system activity was recorded prior to a bogus taste test, which quantified ad libitum consumption of highly-palatable snack foods post-stress. Only the stress + uncertain safety condition exhibited greater sympathetic nervous system activity than the control condition. A significant index of moderated serial mediation emerged for Preoccupation with Dieting and Weight-Focused Restraint in the stress + uncertain safety condition. Though sympathetic activation decreased hunger similarly regardless of dietary restraint, only less restrained individuals significantly decreased intake. More restrained individuals ate more despite experiencing lower hunger. The disconnect between hunger and intake in more restrained eaters suggests that focus on enhancing attunement to hunger may yield greater benefit than enhancing restraint. 281 words.

Do eating behavior traits predict energy intake and body mass index? A systematic review and meta-analysis

At present, it is unclear whether eating behavior traits (EBT) predict objectively measured short-term energy intake (EI) and longer-term energy balance as estimated by body mass index (BMI). This systematic review examined the impact of EBT on BMI and laboratory-based measures of EI in adults ( ≥ 18 years) in any BMI category, excluding self-report measures of EI. Articles were searched up until 28th October 2021 using MEDLINE, PsycINFO, EMBASE and Web of Science. Sixteen EBT were identified and the association between 10 EBT, EI and BMI were assessed using a random-effects meta-analysis. Other EBT outcomes were synthesized qualitatively. Risk of bias was assessed with the mixed methods appraisal tool. A total of 83 studies were included (mean BMI = 25.20 kg/m² , mean age = 27 years and mean sample size = 70). Study quality was rated moderately high overall, with some concerns in sampling strategy and statistical analyses. Susceptibility to hunger (n = 6) and binge eating (n = 7) were the strongest predictors of EI. Disinhibition (n = 8) was the strongest predictor of BMI. Overall, EBT may be useful as phenotypic markers of susceptibility to overconsume or develop obesity (PROSPERO: CRD42021288694).

The Power of Suggestion: Subjective Satiety Is Affected by Nutrient and Health-Focused Food Labelling with No Effect on Physiological Gut Hormone Release

Health claims on food labelling can influence peoples' perception of food without them actually eating it, for example driving a belief that a particular food will make them feel fuller. The aim of this study was to investigate whether nutrient and health claims on food labelling can influence self-reported, and physiological indicators of, satiation. A total of 50 participants attended two visits where they were asked to consume a 380 kcal breakfast (granola and yogurt) labelled as a 500 kcal 'indulgent' breakfast at one visit and as a 250 kcal 'sensible' breakfast at the other. The order of the breakfast descriptions was randomly allocated. Participants were unaware that the two breakfasts were the same product and that only the food labels differed. At each visit blood samples were collected to measure gut hormone levels (acylated ghrelin, peptide tyrosine-tyrosine and glucagon-like peptide-1) at three time points: 20 min after arrival (baseline), after 60 min (anticipatory, immediately prior to consumption) and after 90 min (post-consumption). Visual analogue scales measuring appetite (hunger, satiety, fullness, quantity and desire to eat) were completed prior to each sample. Between 60 and 90 min, participants consumed the breakfast and rated its sensory appeal. Participants reported a higher mean change in self-reported fullness for the 'indulgent' than the 'sensible' breakfast from anticipatory to post-consumption (mean difference: 7.19 [95% CI: 0.73, 13.6]; p = 0.030). This change was not observed for the other appetite measures at the other time points or gut hormone levels. This study suggests that nutrient and health claims on food labels may influence satiation as measured by self-reported fullness. It also suggests that the observed differences in satiety scores are not due to changes in the main appetite regulating gut hormones, but are more likely centrally mediated. More high-quality trials are required to confirm these findings.

Hormonal Factors and Disturbances in Eating Disorders

This review summarizes the current state of the literature regarding hormonal correlates of, and etiologic influences on, eating pathology. Several hormones (e.g., ghrelin, CCK, GLP-1, PYY, leptin, oxytocin, cortisol) are disrupted during the ill state of eating disorders and likely contribute to the maintenance of core symptoms (e.g., dietary restriction, binge eating) and/or co-occurring features (e.g., mood symptoms, attentional biases). Some of these hormones (e.g., ghrelin, cortisol) may also be related to eating pathology via links with psychological stress. Despite these effects, the role of hormonal factors in the etiology of eating disorders remains unknown. The strongest evidence for etiologic effects has emerged for ovarian hormones, as changes in ovarian hormones predict changes in phenotypic and genetic influences on disordered eating. Future studies would benefit from utilizing etiologically informative designs (e.g., high risk, behavioral genetic) and continuing to explore factors (e.g., psychological, neural responsivity) that may impact hormonal influences on eating pathology.

Influence of Nutrition Claims on Appetite Sensations according to Sex, Weight Status, and Restrained Eating

Nutrition claims may help people to adopt healthier eating habits, but little is known about the potential cognitive effects of such claims on appetite sensations. The main purpose of this study was to evaluate the impact of nutrition claims and individual factors on perceived appetite sensations. According to a three ("healthy" versus "diet" (i.e., satiating) versus "hedonic") by two (restrained or not restrained) by two (normal-weight or overweight/obese) by two (men versus women) factorial design, 164 males and 188 females aged 18-65 were invited to taste an oatmeal-raisin snack in a blinded and ad libitum context. Visual analog scales (150 mm) were used to evaluate appetite sensations before and over 1 h after consumption period. BMI and Restraint Scale were used to categorize participants according to their weight and restraint status. No main condition effect was observed for any of the four appetite sensations. However, subgroups analysis revealed significant differences among specific subgroups. A main effect of sex was also observed for all appetite sensations with men reporting higher levels of desire to eat, hunger and prospective food consumption, and lower levels of fullness than women. These findings highlight the importance of considering individual characteristics in interaction when studying appetite sensations.

Twins and endocrinology

Twins are two independent babies delivered during the same pregnancy and are divided as monozygotic or dizygotic based on their origin. Dizygotic twins are similar to two siblings and have different genetic information. In contrary, monozygotic twins have a similar genetic identity and provide a unique opportunity to evaluate the contribution of genetic and environmental factors of the disease. The endocrine and metabolic disorders affect a large number of the population including the twins. Diabetes, obesity, and autoimmune thyroid disease are the most common endocrine disorders in general practice. It is essential to understand the genetic basis of endocrine disorders for therapy, prognostication and risk assessment for future generations. In this article, we review the endocrine disorders in relation to their occurrence in monozygotic twins to highlight the genetic and environmental contribution.