Appetitive Responses Research Articles

The role of meal timing in appetitive responses to acute exercise in adolescents with and without obesity: A systematic review and meta-analysis.

Physical activity has been shown to improve various aspects of metabolic health and is frequently applied as an intervention in the management and prevention of overweight/obesity. Chrono-exercise can be studied in relation to time of day and timing in relation to a meal, which encompasses chronology and duration of the temporal interval, but the latter has received limited attention to date. This brief review and meta-analysis investigates whether the timing of a meal subsequent to acute exercise, in children and adolescents with and without overweight/obesity, moderates eating behaviour and appetite. A quantitative synthesis of 28 controlled trials with 51 distinct conditions (N = 575; median sample size = 15, median age = 13 years, n = 297 overweight/obesity) was performed using multilevel random-effects meta-regressions and restricted splines to test the linear and non-linear relationships between mean differences in energy intake between exercise and control conditions and the duration of the exercise-test meal interval, and if this moderated by participant weight status or exercise characteristics (i.e., intensity, duration, and modality). Commencement of meals occurred from immediately to 3 hours after cessation of exercise (Median = 30 minutes, interquartile range = 8 minutes). The meal interval was not associated with effect sizes overall in the linear and spline analysis (ps = .576 and .971, respectively). Although there was only an interaction with weight status present in the linear analysis (p < .001), the meal interval significantly moderated effect sizes within study arms with lean participants (ps = .006 and .019, respectively), but not in those with overweight/obesity (ps = .070 and .620, respectively) in both analyses. Exercise characteristics did not have an impact on this relationship. Taken together, prescriptions for meal timing may depend on the individual phenotype when seeking to optimise potential anorexigenic effects of acute exercise. PROSPERO REGISTRATION NUMBER: CRD42021287838 (https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=287838).

Pharyngeal neuronal mechanisms governing sour taste perception in Drosophila melanogaster.

Sour taste, which is elicited by low pH, may serve to help animals distinguish appetitive from potentially harmful food sources. In all species studied to date, the attractiveness of oral acids is contingent on concentration. Many carboxylic acids are attractive at ecologically relevant concentrations but become aversive beyond some maximal concentration. Recent work found that Drosophila ionotropic receptors IR25a and IR76b expressed by sweet-responsive gustatory receptor neurons (GRNs) in the labellum, a peripheral gustatory organ, mediate appetitive feeding behaviors toward dilute carboxylic acids. Here, we disclose the existence of pharyngeal sensors in Drosophila melanogaster that detect ingested carboxylic acids and are also involved in the appetitive responses to carboxylic acids. These pharyngeal sensors rely on IR51b, IR94a, and IR94h, together with IR25a and IR76b, to drive responses to carboxylic acids. We then demonstrate that optogenetic activation of either Ir94a+ or Ir94h+ GRNs promotes an appetitive feeding response, confirming their contributions to appetitive feeding behavior. Our discovery of internal pharyngeal sour taste receptors opens up new avenues for investigating the internal sensation of tastants in insects.

Pharyngeal neuronal mechanisms governing sour taste perception in Drosophila melanogaster

Sour taste, which is elicited by low pH, may serve to help animals distinguish appetitive from potentially harmful food sources. In all species studied to date, the attractiveness of oral acids is contingent on concentration. Many carboxylic acids are attractive at ecologically relevant concentrations but become aversive beyond some maximal concentration. Recent work found that Drosophila ionotropic receptors IR25a and IR76b expressed by sweet-responsive gustatory receptor neurons (GRNs) in the labellum, a peripheral gustatory organ, mediate appetitive feeding behaviors toward dilute carboxylic acids. Here, we disclose the existence of pharyngeal sensors in Drosophila melanogaster that detect ingested carboxylic acids and are also involved in the appetitive responses to carboxylic acids. These pharyngeal sensors rely on IR51b, IR94a, and IR94h, together with IR25a and IR76b, to drive responses to carboxylic acids. We then demonstrate that optogenetic activation of either Ir94a+ or Ir94h+ GRNs promotes an appetitive feeding response, confirming their contributions to appetitive feeding behavior. Our discovery of internal pharyngeal sour taste receptors opens up new avenues for investigating the internal sensation of tastants in insects.

Chronotypical influence on eating behaviour and appetite control.

A person's chronotype reflects individual variability in diurnal rhythms for preferred timing of sleep and daily activities such as exercise and food intake. The aim of this review is to provide an overview of the evidence around the influence of chronotype on eating behaviour and appetite control, as well as our perspectives and suggestions for future research. Increasing evidence demonstrates that late chronotype is associated with adverse health outcomes. A late chronotype may exacerbate the influence of greater evening energy intake on overweight/obesity risk and curtail weight management efforts. Furthermore, late chronotypes tend to have worse diet quality, with greater intake of fast foods, caffeine and alcohol and lower intake of fruits and vegetables. Late chronotype is also associated with eating behaviour traits that increase the susceptibility to overconsumption such as disinhibition, food cravings and binge eating. Whether an individual's chronotype influences appetite in response to food intake and exercise is an area of recent interest that has largely been overlooked. Preliminary evidence suggests additive rather than interactive effects of chronotype and meal timing on appetite and food reward, but that hunger may decrease to a greater extent in response to morning exercise in early chronotypes and in response to evening exercise in late chronotypes. More studies examining the interplay between an individual's chronotype, food intake/exercise timing and sleep are required as this could be of importance to inform personalised dietary and exercise prescriptions to promote better appetite control and weight management outcomes.

The Effect of High Protein-High Fat and High Protein-High Carbohydrate Meals on Resting Metabolic Rate and Metabolic Factors in Overweight and Obese Adults: The Study Protocol for a Randomized Crossover Clinical Trial

Background: The macronutrient composition of daily meals plays a crucial role in influencing the body's metabolic responses during the postprandial phase. However, existing research on the effects of macronutrients, particularly fats and carbohydrates, has produced inconsistent findings. Objectives: This study aims to evaluate the postprandial effects of two high-protein meals—one low in fat and high in carbohydrates (HP-LF-HC) and the other high in fat and low in carbohydrates (HP-HF-LC)—on energy metabolism, appetite response, and blood markers in overweight and obese men and women without underlying health conditions. Methods: This study was conducted as an acute randomized crossover clinical trial at the Health Monitoring Center of Mashhad University of Medical Sciences (MUMS) within Imam Reza Hospital, Mashhad, Iran. A total of 30 overweight and obese men and women, meeting the eligibility criteria and free of underlying diseases, were recruited through a public call. Participants were randomly assigned to receive both intervention meals, with a washout period of at least one week between each trial. Results: The primary outcomes focused on the acute effects of the two dietary interventions on energy metabolism, particularly resting metabolic rate (RMR), and appetite response. Secondary outcomes included changes in lipid profiles, insulin, blood glucose levels, thyroid hormones, and epinephrine. Conclusions: This study aims to identify which macronutrient composition most effectively enhances resting energy expenditure. The findings could provide valuable insights for dietitians in developing more efficient dietary plans, helping overweight and obese individuals maintain an ideal weight or achieve weight loss by modifying food composition without altering meal volume.

Association between infant feeding behavior and maternal choice of breastfeeding type

Abstract Introduction Feeding in infants is a fundamental process influenced by the mother-child relationship during the early months of life. The regulation of feeding behavior, and hunger and satiety cues may be interpreted by the mother, potentially relating to the type of feeding chosen. Objectives To determine the association between infant feeding behavior and the type of breastfeeding chosen by the mother. Methods A cross-sectional and prospective study was conducted, including mothers with children aged between 6 and 18 months. Those with medical contraindications for immediate postpartum breastfeeding or with suspension of exclusive breastfeeding during the first 6 months of life due to medical prescription were excluded. The Baby Eating Behavior Questionnaire was used to evaluate the baby’s enjoyment of food, appetite response, eating speed, and satiety response. Results 108 mothers were included, with 87% in agreement with exclusive breastfeeding (EBF), 43.3% using breastfeeding as the primary feeding method, and only 33.3% practicing EBF during the first 6 months. Food response (FR) scored 19.6 (±4.3), enjoyment of food (EF) 17.6 (±2.1), satiety response (SR) 7.1 (±2.0), eating speed (ES) 8.8 (±2.3), and appetite (AP) 4.2 (±0.7). Comparing FR, EF, SR, ES, and AP scores between those who practiced EBF and those who did not showed p &amp;gt; 0.05. sociodemographic characteristics, perinatal factors, stance on EBF, number of hours per day with the child, feeding location, poor technique, breastfeeding pain and lack of medical guidance, all showed p &amp;gt; 0.05 when comparing between those who practiced EBF and those who did not; in contrast to perceiving that the baby wanted to breastfeed (2.5/1.0-6.2), having time to feed (3/1.2-7.2) and having no health problems (10/1.2-78.7) all with p-value &amp;lt;0.05. Conclusions The mother’s perception identifying the baby’s desire to breastfeed, having time to feed the baby and not having health problems favor exclusive breastfeeding. Key messages • Maternal perception plays an important role in deciding to give SCI, so it is the physician’s job to educate the mother so that she has additional arguments for choosing SCI. • The infant’s feeding behavior does not have a significant impact on the mother’s behavior in choosing SCI feeding.

Emotional food craving across the eating disorder spectrum: an ecological momentary assessment study

PurposeEmotional eating during negative emotions might underlie disordered eating behavior (i.e., binge eating and food restriction). Positive emotions, by contrast, seem to promote healthier eating behavior. Naturalistic research on the links between emotions and eating across individuals with binge-eating disorder (BED), bulimia nervosa (BN), binge-purge anorexia nervosa (AN-BP), and restrictive anorexia nervosa (AN-R) is, however, lacking.MethodsIndividuals without eating disorders (comparison group, CG, n = 85), and patients with BED (n = 41), BN (n = 50), AN-BP (n = 26), and AN-R (n = 29) participated in an ecological momentary assessment study. Six daily notifications over eight days prompted ratings of momentary food craving and emotional states differing in valence and arousal.ResultsResults supported specific emotion-food-craving patterns in each group. Compared to the CG, arousing negative emotions and higher cravings co-occurred in patients with BN. In patients with AN-BP (at trend level also in patients with AN-R) less arousing negative emotions and lower cravings co-occurred. In patients with AN, positive emotions and higher cravings co-occurred whereas in patients with BED less arousing positive emotions and lower cravings co-occurred.ConclusionThe found emotion-craving associations may underlie group-specific (dys-)functional eating behaviors, i.e., binge eating and food restriction during negative emotions in patients with BN and AN, and normalized appetitive responses during positive emotions in patients with BED and AN. Therapeutic efforts could target arousing negative emotions in patients with BN, and less arousing negative emotions in patients with AN. Positive emotions could be used in a salutogenetic approach in patients with BED and AN.

Acute exercise might not affect subsequent appetite responses to a fixed meal in adolescents with obesity: The SMASH exploratory study

While an intensity-dependent post-exercise decrease in energy intake (EI) has been described in adolescents with obesity, studies invariably used ad libitum meals, limiting then any conclusions regarding the effect of exercise on post-meal appetitive responses that can be also impacted by the ad libitum nature of the meal. This study analyses appetite and food-reward related responses to a fixed meal after an acute exercise, also exploring the associations between substrate use during exercise and overall daily EI in adolescents with obesity. Thirteen adolescents with obesity (12–16 years, 5 males) randomly complete 2 experimental sessions: (i) a control condition (CON); (ii) a 30-min moderate intensity (65% VO2peak) cycling condition (EX). Energy expenditure and substrate oxidation were measured during both 30 min of rest (CON) or exercise (EX). Ad libitum EI, macronutrient intake and relative EI were assessed at dinner, subjective appetite sensations taken at regular intervals and food reward measured before and after lunch as well as before dinner. Energy and macronutrient intake did not differ between conditions, as well as appetite feelings. A time effect (p = 0.012) was observed between pre and post meal for choice fat bias in both conditions but was only significant within the CON condition (p = 0.004). CHO oxidation during exercise was found correlated with both EI (r = 0.586, p = 0.045), pre-lunch hunger (r = 0.624, p = 0.030), daily AUC for hunger and DTE (r = 0.788, p = 0.002 and r = 0.695; p = 0.012 respectively). This exploratory study highlights that acute exercise might not affect subsequent appetite responses when using a fixed test meal in adolescents with obesity.

Changes in appetite during acute passive intermittent and continuous hypoxemia in postprandial and fasting states: A combined analysis of four laboratory-based randomized crossover trials

Hypoxemia occurs during exposure to high altitude (continuous hypoxemia) or in the context of breathing disorders such as obstructive sleep apnea (OSA; intermittent hypoxemia). Growing evidence demonstrates that hypoxemia induces an anorexigenic effect on appetite; however, few studies have assessed hypoxemia-related reductions in appetite during acute passive exposures and during intermittent hypoxemia. This study thus pooled together four same-single-site randomized crossover trials using simulated models of high altitude (fraction of inspired oxygen = 0.1200, ∼5000 m) and moderate OSA (∼15 hypoxemic cycles per hour, ∼85 oxyhemoglobin saturation). Changes in appetite were evaluated during 6 h of passive normoxia and intermittent or continuous hypoxemia in postprandial or fasting states among healthy young adults (n = 40) and middle-aged individuals living with OSA (n = 7). Our results demonstrate that (1) acute passive intermittent hypoxemia leads to statistically significant, but likely not clinically significant reductions in appetite in the postprandial state, (2) the anorexigenic effect of acute passive hypoxemia on appetite is not consistent across hypoxemic methods and nutritional states, and (3) variations in individual factors may influence appetite responses during normoxia and hypoxemia. These findings indicate that the effect of acute passive hypoxemia on appetite is heterogeneous, particularly across different hypoxemic methods and nutritional states.

Growth performance of eel fish (Anguilla bicolor) which are maintained in containers of different colors

Performance of Eel (Anguilla bicolor) maintened in containers of different colors. Growth is the main driver in increasing the profitability of aquaculture. In addition to maintenance management the color of the container is also a factor supporting the growth of eels. This study aims to determine the effect of the color of different rearing containers on the growth and appetite response of eel. The test fish used were elver stage eels with an average weight (129 ±131g). The method used is an experiment with two treatments they are grey and green. The test fish were placed in a container measuring 19x4 m2 and a water level of 1m with a stocking density of 1100 individuals each, 30 days of rearing. The variables observed were growth performance including SR (Survival Rate), ADG (Average Daily Growth), FCR (Food Conversion Ratio), SGR (Specific Growth Rate). The results obtained indicated that there was a significant difference in the average growth of fish reared in grey and green containers. Grey container treatment was proven to get higher yields with average final weight values (192.4 ± 4.5 g), FCR (1.01 ± 0.02), ADG (2.01g/day ± 0.06), SGR (1 .25%BW/day±0.02). Based on the results of the study it can be concluded that there is a significant difference in the growth of eels reared in ash and green containers. The color of the ash container proved to be better in supporting growth performance.Keywords: Elver; Green; Grey; Nocturnal

Histamine H3 receptor activation in the insular cortex during taste memory conditioning decreases appetitive response but accelerates aversive memory extinction under an ad libitum liquid regimen

Conditioned taste aversion (CTA) is a robust associative learning; liquid deprivation during this conditioning allows researchers to obtain readable measures of associative learning. Recent research suggests that thirst could be a crucial motivator that modulates conditioning and memory extinction processes, highlighting the importance of the body’s internal state during learning. Furthermore, the histaminergic system is one of the major modulatory systems controlling several behavioral and neurobiological functions, such as feeding, water intake, and nociception. Therefore, this research aimed to assess the effect of H3 histaminergic receptor activation in the insular cortex (IC) during CTA. For this, we conditioned adult male Wistar rats under two regimens: water deprivation and water ad libitum. A classical CTA protocol was used for water deprivation. Before CTA acquisition, 10 μM R-α-methylhistamine (RAMH), an H3 receptor agonist, was injected into the IC. Results showed that RAMH injections decreased CTA in water-deprived rats without affecting the significant aversion conditioning in rats that were given water ad libitum. Moreover, RAMH accelerated the process of aversive memory extinction under ad libitum water conditions. According to our findings, the degree of liquid satiety differentially affected taste-aversive memory formation, and H3 histamine receptors were more involved under water deprivation conditions during acquisition. However, these receptors modulated the strength of aversive conditioning by altering the rate of aversive memory extinction in the absence of deprivation. In conclusion, histaminergic activity in the IC may influence taste memory dynamics through different mechanisms depending on the degree of liquid satiety or deprivation during conditioning.

Postprandial appetite responses to a pecan enriched meal: A randomized crossover trial

Longer-term pecan consumption has shown appetite-regulating effects as a part of a free-living diet, yet the physiologic appetite responses to a single pecan-containing meal are unclear. The purpose of this study was to compare the acute physiologic, subjective, and direct appetite responses of a pecan-containing meal to an energy- and macronutrient-matched control meal. This was an acute meal challenge study utilizing a double-blinded randomized crossover design with two periods. Participants were young, healthy adults (BMI: 22.9 ± 3.3 kg/m2, age: 22 ± 3 y) who consumed a meal containing either 68 g of pecans (PEC; 795 kcal) or an energy- and macronutrient-matched control meal (CON; 794 kcal) on separate testing days. At both testing visits, five postprandial blood draws, and visual analog scale (VAS) questionnaires (in-lab) were used to determine differences in peptide YY (PYY), ghrelin, and subjective appetite over a 4-h postprandial period. Participants also completed VAS questionnaires (at-home) and food records for the rest of the day after leaving the testing visits. Thirty-one out of thirty-two randomized participants completed the study. There was a greater overall postprandial PYY response (p < 0.001), and a greater suppression of postprandial ghrelin after time point 120 min (p < 0.001), with the PEC vs. CON meal. Further, there was a greater increase in subjective fullness (p = 0.001), and suppression of at-home overall appetite (p = 0.02), from time 240–780 min post-meal with PEC vs. CON meals. There were no differences in self-reported EI between meals or any other VAS measure. In conclusion, a pecan-containing breakfast shake produced more favorable physiologic and subjective improvements in appetite compared to an energy- and macronutrient-matched control meal. This trial is registered at clinicaltrials.gov (NCT05230212).

Individual variability and consistency of post-exercise energy and macronutrient intake, appetite sensations, and food reward in healthy adults

Limited evidence is available about the variability of appetitive responses within individuals after an acute bout of exercise. The present study aimed to assess the consistency and individual variability of post-exercise appetitive responses in healthy individuals. Twenty participants (10 females, 23.9 ± 4.1 years, 22.5 ± 2.0 kg m−2) joined the laboratory to perform four sessions separated by a minimum of 5 days: i) a control session with a rest period before and an ad libitum lunch (REST), and ii) three identical exercise sessions (EX) with a 30-min moderate-intensity (60–70% of predicted maximal heart rate) walking bout ending 25 min before the ad libitum lunch. Subjective appetite sensations were assessed before and after the meal at regular intervals, and satiety quotients were calculated. Food reward was assessed by the Leeds Food Preference Questionnaire before and after lunch. For each EX session, the difference with the REST session was calculated (Δ = EX – REST). Energy and macronutrient intake were consistent in response to exercise (all intraclass correlation coefficients (ICC) > 0.8) while results showed that post-exercise subjective appetite sensations and satiety quotients varied across the three EX sessions (almost all ICC < 0.7). Food reward was overall consistent in response to exercise before the test meal but not after. When considering the changes (Δ), the results showed no or poor consistency for most of the appetitive outcomes. To conclude, energy and macronutrient intake, as well as pre-meal food reward, are consistent after exercise in healthy individuals, while subjective appetite sensations are not stable within individuals across the sessions. Regarding the variations from REST to EX sessions, the results suggest that the individual changes observed are only random day-to-day variations.

Effects of acute consumption of a beverage based on extruded whole-grain pearl millet flour on glycemic and insulinemic control, food intake, and appetite sensation in eutrophic adults: A randomized cross-over clinical trial

ObjectivesWhole-grain pearl millet is a nutritious cereal source of dietary fiber, vitamins, minerals, and bioactive compounds. It offers health benefits such as glycemic control and satiety. Extrusion cooking for diverse formulations, including beverages, can alter its chemical composition, impacting the nutritional value. This study aimed to evaluate the sensory acceptability of an extruded millet flour beverage and its acute effects on glycemic index (GI), glycemic and insulinemic response, food intake, and subjective appetite sensations in euglycemic and eutrophic adults. MethodsThis is an acute, single-blind, randomized, controlled, cross-over clinical study comprising 14 euglycemic and eutrophic adults. Initially, beverages based on whole extruded millet flour were developed, and sensorially and chemically analyzed. Next, a clinical trial was conducted with participants undergoing four sessions and consuming one of the following options: extruded millet beverage, a maltodextrin control beverage, or a glucose solution administered in two separate sessions. Blood glucose, insulin, and appetite responses were assessed over a 2-h period, in addition to determining the GI of the beverages and analyzing food intake in the 24 h following each session. ResultsThe extruded millet flour strawberry-flavored beverage had the best sensory acceptance and was classified as having as high GI. Consumption of the extruded millet beverage showed similar glycemic and insulinemic responses, as well as appetite control and food intake of the subjects, when compared with consumption of the maltodextrin control beverage. ConclusionsIntake of the extruded millet beverage maintained glycemic and insulinemic responses, appetite control, and food intake in euglycemic and eutrophic subjects.

Appetite, food intake, and gut hormone responses to glycomacropeptide protein ingestion in older adults: A feasibility, acceptability, and pilot study

Glycomacropeptide (GMP) has a unique amino acid profile which may make less satiating than other dietary proteins. This study assessed the feasibility and likely acceptability of a leucine-enriched GMP drink and determined appetite response in older adults (OA). Thirteen OA (11f; 70 ± 4 years) were recruited for sensory assessments of a leucine-enriched GMP drink when mixed with water and with fruit smoothie, compared with whey protein isolate (WHEY). Participants also partook in a single focus group exploring acceptability to protein and supplementation. Separately, a counterbalanced, double-blind study with twelve OA (8f; 69 ± 3 years) was conducted to determine appetite and gut hormone responses. Fasting subjective appetite was recorded using visual analogue scales and a fasted venous blood sample was collected (to measures acyl-ghrelin, PYY, GLP-1, and CCK) before participants consumed either: GMP protein (27g + 3g leucine, 350 mL water), WHEY (30g, 350 mL water), or water. Participants rested for 240 min, with appetite measures and blood sampling throughout. An ad libitum pasta-based meal was then consumed. Sensory testing revealed low pleasantness rating for GMP in water vs. WHEY (16 ± 14 vs 31 ± 24, p = 0.016). GMP addition to smoothie reduced pleasantness (26 ± 21 vs. 61 ± 29, p = 0.009) and worsened the aroma (46 ± 15 vs. 69 ± 28, p = 0.014). The focus group revealed uncertainty of protein needs and a scepticism of supplements, with preference for food. Gut hormone response did not differ between GMP and WHEY (nAUC for all gut hormones p > 0.05). There was no difference between conditions for lunch ad libitum intake (549 ± 171 kcal, 512 ± 238 kcal, 460 ± 199 kcal for GMP, WHEY, and water, p = 0.175), or for subjective appetite response. Leucine-enriched GMP was not less satiating than WHEY, and low palatability and scepticism of supplements question the likely acceptability of GMP supplementation. Providing trusted nutritional advice and food enrichment/fortification may be preferred strategies for increasing protein intake in OA.

Role of Dorsal Raphe Serotonergic Neurons in the Regulation of Sodium Appetite

An animal with sodium deficiency develops sodium appetite which drives it to consume more sodium. A lot of studies have been performed to understand how sodium depletion may lead to the development of sodium appetite, but there are still unanswered questions. In particular, while the relationship between serotonin receptors and sodium appetite has been identified in previous studies, it is still unclear how serotonergic neurons control sodium appetite in response to sodium depletion. In this study, we focused on serotonergic neurons in the dorsal raphe nucleus (DRN) which releases more than 50% of serotonin in the brain. We found that DRN serotonergic neurons are activated in response to sodium depletion. In addition, we found evidence that angiotensin II is a key molecule herein to evoke sodium appetite in sodium depletion. Our results provide refined insight how sodium appetite develops in sodium depletion. This work was supported by grants from Samsung Science &amp; Technology Foundation (SSTF-BA1901-11) to Jong-Woo Sohn. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Twenty four-hour passive heat and cold exposures did not modify energy intake and appetite but strongly modify food reward.

Effects of acute thermal exposures on appetite appear hypothetical in reason of very heterogeneous methodologies. The aim of this study was therefore to clearly define the effects of passive 24-h cold (16°C) and heat (32°C) exposures on appetitive responses compared with a thermoneutral condition (24°C). Twenty-three healthy, young and active male participants realised three sessions (from 13.00) in a laboratory conceived like an apartment dressed with the same outfit (Clo = 1). Three meals composed of three or four cold or warm dishes were served ad libitum to assess energy intake (EI). Leeds Food Preference Questionnaires were used before each meal to assess food reward. Subjective appetite was regularly assessed, and levels of appetitive hormones (acylated ghrelin, glucagon-like peptite-1, leptin and peptide YY) were assessed before and after the last meal (lunch). Contrary to the literature, total EI was not modified by cold or heat exposure (P = 0·120). Accordingly, hunger scores (P = 0·554) were not altered. Levels of acylated ghrelin and leptin were marginally higher during the 16 (P = 0·032) and 32°C (P < 0·023) sessions, respectively. Interestingly, implicit wanting for cold and low-fat foods at 32°C and for warm and high-fat foods at 16°C were increased during the whole exposure (P < 0·024). Moreover, cold entrées were more consumed at 32°C (P < 0·062) and warm main dishes more consumed at 16°C (P < 0·025). Thus, passive cold and hot exposures had limited effects on appetite, and it seems that offering some choice based on food temperature may help individuals to express their specific food preferences and maintain EI.

Deacetylated Konjac Glucomannan with a Slower Hydration Rate Delays Rice Digestion and Weakens Appetite Response.

The physical characteristics of chyme during gastrointestinal digestion are considered to significantly affect nutrient digestion and absorption (such as glucose diffusion), which has an impact on postprandial satiety. The present study aims to analyze the hydration rate (HR) and rheological properties of deacetylated konjac glucomannan (DKGM) at different degrees and then explore their effects on rice texture, digestive properties, and the subjects' post-meal appetite. The present results show that, as the deacetylation degree (DD) of KGM increased, the intersection point of the viscoelastic modulus shifted to a high shear rate frequency, and as the swelling time of the DKGM was prolonged, its HR decreased significantly. The results of the in vitro gastrointestinal digestion tests show that the hardness and chewability of the rice in the fast-hydration group (MK1) were remarkably reduced. In contrast, the slow-hydration group (MK5) exhibited an outstanding ability to resist digestion. The kinetics of starch hydrolysis revealed that the HR of the rice in the fast-hydration group was 1.8 times faster than that of the slow-hydration group. Moreover, it was found that the subjects' appetite after the meal was highly related to the HR of the MK. Their hunger (p < 0.001), desire to eat (p < 0.001), and prospective food consumption (p < 0.001) were significantly inhibited in the slow-hydration group (MK5) compared to the control. This study explored the nutritional effects of the hydration properties derived from the DKGM, which may contribute to modifying the high glycemic index food and provide ideas for the fabrication of food with enhanced satiating capacity.

Postprandial plasma amino acid and appetite responses with ingestion of a novel salmon-derived protein peptide in healthy young adults.

This study assessed postprandial plasma aminoacidemia, glycemia, insulinemia and appetite responses to ingestion of a novel salmon-derived protein peptide (Salmon PP) compared with milk protein isolate (Milk PI). In a randomised, participant-blind crossover design, eleven healthy adults (M = 5, F = 6; mean ± sd age: 22 ± 3 years; BMI: 24 ± 3 kg/m2) ingested 0·3 g/kg/body mass of Salmon PP or Milk PI. Arterialised blood samples were collected whilst fasted and over a 240-min postprandial period. Appetite sensations were measured via visual analogue scales. An ad libitum buffet-style test meal was administered after each trial. The incremental AUC (iAUC) plasma essential amino acid (EAA) response was similar between Salmon PP and Milk PI. The iAUC plasma leucine response was significantly greater following Milk PI ingestion (P < 0·001), whereas temporal and iAUC plasma total amino acid (P = 0·001), non-essential amino acid (P = 0·002), glycine (P = 0·0025) and hydroxyproline (P < 0·001) responses were greater following Salmon PP ingestion. Plasma insulin increased similarly above post-absorptive values following Salmon PP and Milk PI ingestion, whilst plasma glucose was largely unaltered. Indices of appetite were similarly altered following Salmon PP and Milk PI ingestion, and total energy and macronutrient intake during the ad libitum meal was similar between Salmon PP and Milk PI. The postprandial plasma EAA, glycine, proline and hydroxyproline response to Salmon PP ingestion suggest this novel protein source could support muscle and possibly connective tissue adaptive remodelling, which warrants further investigation, particularly as the plasma leucine response to Salmon PP ingestion was inferior to Milk PI.

Testing detectability, attractivity, hedonic specificity, extractability, and robustness of colostrum odor-Toward an olfactory bioassay for human neonates.

Human milk odor is attractive and appetitive for human newborns. Here, we studied behavioral and heart-rate (HR) responses of 2-day-old neonates to the odor of human colostrum. To evaluate detection in two conditions of stimulus delivery, we first presented the odor of total colostrum against water. Second, the hedonic specificity of total colostrum odor was tested against vanilla odor. Third, we delivered only the fresh effluvium of colostrum separated from the colostrum matrix; the stability of this colostrum effluvium was then tested after deep congelation; finally, after sorptive extraction of fresh colostrum headspace, we assessed the activity of colostrum volatiles eluting from the gas chromatograph (GC). Regardless of the stimulus-delivery method, neonates displayed attraction reactions (HR decrease) as well as appetitive oral responses to the odor of total colostrum but not to vanilla odor. The effluvium separated from the fresh colostrum matrix remained appetitive but appeared labile under deep freezing. Finally, volatiles from fresh colostrum effluvium remained behaviorally active after GC elution, although at lower magnitude. In sum, fresh colostrum effluvium and its eluate elicited a consistent increase in newborns' oral activity (relative to water or vanilla), and they induced shallow HR decrease. Newborns' appetitive oral behavior was the most reproducible response criterion to the effluvium of colostrum. In conclusion, a set of unidentified volatile compounds from human colostrum is robust enough after extraction from the original matrix and chromatographic processing to continue eliciting appetitive responses in neonates, thus opening new directions to isolate and assay specific volatile molecules of colostrum.