A systematic review of associations between day-to-day variability in meal pattern and body weight, components of the metabolic syndrome and cognitive function.

BACKGROUND: Meal pattern is a potential health determinant. Previously, mean values for properties of meal pattern, such as daily meal frequency, have been considered. Means, however, obscure variability between-day (irregular or chaotic eating). This systematic review aimed to identify and critique published methods used to characterise between-day variability in meal pattern, and to explore relationships between this and obesity, as well as associated health outcomes. METHODS: Using relevant databases, a systematic search was undertaken for studies with adults and children in which between-day variability in meal pattern was measured, and related to body weight, metabolic syndrome components and cognitive function. RESULTS: In 34 papers identified (28 observational and six intervention studies), between-day variability in meal pattern was characterised by a variety of methods. These ranged from single questions about intake regularity to more complex methods quantifying the degree of variability. Assumptions were made, such as there being three main meals, resulting in dissociation from the "clock time" of eating. In 24 of the papers, between-day variability in meal pattern was associated with negative weight and health outcomes including higher weight, reduced thermogenic response to meals and poorer academic achievement. CONCLUSIONS: Between-day variability in meal pattern is a promising research area that might inform low-cost public health interventions. However, current methods of characterising between-day variability tend to make assumptions and be inconsistent in the meal pattern properties considered. Well controlled dietary intervention studies are required to confirm causation.

Associations of chronotype and social jetlag with eating jetlag and their changes among German students during the first COVID-19 lockdown. The Chronotype and Nutrition study.

Due to their biologically later chronotype, young students are vulnerable to a discrepant sleeping pattern between work- and free days, coined social jetlag (SJL). This study examined whether a later chronotype and/or a larger SJL are related to an analogous discrepancy in meal timing defined as eating jetlag (EJL) and whether chronotype and/or changes in SJL during the first COVID-19 related lockdown in Germany associated with changes in EJL. Baseline data were collected from September 2019-January 2020 among 317 students (58% females) aged 18-25 years of which a total of 156 students (67% females) completed an online follow-up survey in June-July 2020 (1st lockdown). Data were collected on daily routines, timing of meals/snacks, and physical activity. Chronotype was determined using the Munich ChronoType Questionnaire; SJL and EJL correspond to the difference in the daily midpoint of sleep/eating duration between work- and free days. Multivariable linear regression revealed that students with a later chronotype or a larger SJL experienced a larger EJL (padjusted = 0.0124 and padjusted<0.0001). A later chronotype at baseline and reductions in SJL during lockdown associated with concurrent reductions in EJL (padjusted = 0.027 and padjusted<0.0001). In conclusion, students with a later chronotype exhibit a more erratic meal pattern, which associates with SJL. During lockdown, flexible daily schedules allowed students to align the meal timing with their inner clock.

Effect of Growth Hormone Secretagogue Receptor Deletion on Growth, Pulsatile Growth Hormone Secretion, and Meal Pattern in Male and Female Mice.

INTRODUCTION: While the vast majority of research investigating the role of ghrelin or its receptor, GHS-R1a, in growth, feeding, and metabolism has been conducted in male rodents, very little is known about sex differences in this system. Furthermore, the role of GHS-R1a signaling in the control of pulsatile GH secretion and its link with growth or metabolic parameters has never been characterized. METHODS: We assessed the sex-specific contribution of GHS-R1a signaling in the activity of the GH/IGF-1 axis, metabolic parameters, and feeding behavior in adolescent (5-6 weeks old) or adult (10-19 weeks old) GHS-R KO (Ghsr-/-) and WT (Ghsr+/+) male and female mice. RESULTS: Adult Ghsr-/- male and female mice displayed deficits in weight and linear growth that were correlated with reduced GH pituitary contents in males only. GHS-R1a deletion was associated with reduced meal frequency and increased meal intervals, as well as reduced hypothalamic GHRH and NPY mRNA in males, not females. In adult, GH release from Ghsr-/- mice pituitary explants ex vivo was reduced independently of the sex. However, in vivo pulsatile GH secretion decreased in adult but not adolescent Ghsr-/- females, while in males, GHS-R1a deletion was associated with reduction in pulsatile GH secretion during adolescence exclusively. In males, linear growth did not correlate with pulsatile GH secretion, but rather with ApEn, a measure that reflects irregularity of the rhythmic secretion. Fat mass, plasma leptin concentrations, or ambulatory activity did not predict differences in GH secretion. DISCUSSION/CONCLUSION: These results point to a sex-dependent dimorphic effect of GHS-R1a signaling to modulate pulsatile GH secretion and meal pattern in mice with different compensatory mechanisms occurring in the hypothalamus of adult males and females after GHS-R1a deletion. Altogether, we show that GHS-R1a signaling plays a more critical role in the regulation of pulsatile GH secretion during adolescence in males and adulthood in females.

Meal-specific dietary patterns and their contribution to habitual dietary patterns in the Iranian population.

Recent studies have focused on habitual intake without addressing meal-specific intakes. We aimed to identify meal-specific dietary patterns and their contribution to habitual dietary patterns. This cross-sectional study was conducted on 838 adults, both sexes who attended the health centres in Tehran. Dietary data were recorded by three 24-h dietary recalls (24hDR). Dietary patterns were identified by using principal component analysis on meal-specific and overall food intakes. Intraclass correlation (ICC) was used as a measurement of consistency across meals and days. Correlation analysis and linear regression (partial R2) were used for meals contribution. Four habitual dietary patterns were derived from average dietary intake of 3-d 24hDR labelled as 'Western', 'Healthy', 'Traditional' and 'Legume and broth'. Also, we identified two major dietary patterns on each meal level (factor 1 and 2 for breakfast, lunch, afternoon snack and dinner). The highest contribution of energy intake was observed in lunch (25·7 %), followed by dinner (20·81 %). Consistency of food groups was the highest across days (ICC tea = 0·58) and breakfasts (ICC tea = 0·60). Dinner had a strong correlation coefficient with the 'Western' habitual dietary pattern then followed by lunch. Similarly, dinner and lunch contributed the most (r and partial R2) to the 'Western' habitual dietary pattern. Our results suggest that habitual dietary patterns to several extents are formed at meal levels, and dinner has a greater contribution to the habitual dietary patterns in Iranian people. This may help planning for local dietary guidelines according to the time of eating to promote public health.

The relationship between the risk of eating disorder and meal patterns in University students.

PURPOSE: This study was carried out to evaluate the relation between meal patterns and the risk of eating disorders in university students. METHODS: The study was conducted on a total of 331 volunteer students with a mean age of 22.08 ± 1.80 years, 56.5% female. Participants' sociodemographic characteristics, health information and eating habits like meal skipping and dieting were questioned. Sick, Control, One stone, Fat, Food (SCOFF) Eating Disorders Scale and Eating Disorder Examination Questionnaire (EDE-Q) were used to determine eating behavior disorders, with face to face interviews by the researches. RESULTS: A significant correlation was found between dieting and skipping meals and the risk of eating disorders in both genders (p < 0.05). In addition, when the reasons for skipping meals were questioned, a significant relationship was detected between skipping meals and eating behaviour disorders by 3.285 times (p = 0.000). Also, every unit of increase in body mass index (BMI) values of individuals who participated to the study led to an increase in eating disorders by a factor of 1.262 (p = 0.000). CONCLUSIONS: Our findings support concerns about the negative health effects of increasing overweight among university students in accordance with the data that the increase in BMI values led to an increase in eating disorders. Notably a significant correlation was found between dieting, skipping meals and the risk of eating disorders in both genders it is highlighting the need for monitoring and early diagnosis of eating disorders in youth with simple scales like SCOFF. LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.

Breakfast Frequency Is Inversely Associated with Weight Gain in a Cohort of Mexican Women.

BACKGROUND: Food timing affects circadian rhythms involved in weight control. Regular consumption of breakfast may affect body weight. OBJECTIVE: We examined the relation between breakfast frequency with weight change in middle-age women over a 3-y period. METHODS: We used data from 65,099 nonpregnant women aged >20 y participating in the Mexican Teachers' Cohort (MTC) who at baseline (2006-2008) were cancer free and for whom self-reported breakfast frequency at baseline was available. We analyzed body weight change between baseline and the first follow-up (2011) according to breakfast frequency. Participants were classified according to baseline breakfast frequency 0, 1-3, 4-6, or 7 d/wk and meal frequency 1-2, 3-4, or ≥5 meals/d. We used linear and modified Poisson regression to analyze body weight change as a continuous variable and for weight gain ≥5 kg (yes/no), respectively. Models were adjusted for sociodemographic and lifestyle confounders. RESULTS: At baseline, 25% of participants were daily breakfast consumers and 18.4% of women increased ≥5 kg between 2008 and 2011. The prevalence of weight gain ≥5 kg among daily breakfast consumers was 7% lower than among those who skipped breakfast (prevalence ratio: 0.93; 95% CI: 0.89, 0.97; P-trend = 0.02). The association was stronger among normal-weight women at baseline with a corresponding estimate of 0.87 (95% CI: 0.79, 0.97; P-trend = 0.02). CONCLUSION: Daily breakfast consumption was inversely associated with weight gain ≥5 kg over 3 y in middle-aged Mexican women. Regular breakfast may be an important dietary factor for body weight change.

Rats Self-Select a Constant Protein-to-Carbohydrate Ratio Rather Than a Constant Protein-to-Energy Ratio and Have Low Plasma FGF21 Concentrations.

BACKGROUND: Under dietary self-selection (DSS), rats ingest 25-30% of energy as protein. This high level appears to be explained by metabolic benefits related to reduced carbohydrate dependence and associated pathologies. However, the mechanisms underlying these choices remain largely misunderstood. OBJECTIVES: The aim was to test the hypothesis that in a DSS model, rats select a protein-to-energy (PE) ratio to maintain the protein-to-carbohydrate (PC) ratio constant and that fibroblast growth factor 21 (FGF21) is involved in this response. METHODS: Adult male Wistar rats were used in 3 experiments. The first was to determine whether the PE ratio was influenced by changes in carbohydrate content. The second was to test whether the PE ratio was defended with a modified DSS model. The third was to determine whether the selected PE ratio was of metabolic interest compared with a standard 15% protein diet. Food intake, body weight, and energy expenditure were measured. After 3 wk, plasma was sampled and rats were killed to determine body composition and gene expression. Statistical analyses were mainly done by ANOVA tests and correlation tests. RESULTS: The selected PE ratio increased from 20% to 35% when the carbohydrate content of the protein-free diet increased from 30% to 75% (R2 = 0.56; P < 10-6). Consequently, the PC ratio was constant (70%) in all groups (P = 0.18). In self-selecting rats, plasma FGF21 concentrations were 3 times lower than in rats fed the 5% protein diet (P < 10-4) and similar to those in rats fed a 30% diet. CONCLUSIONS: This study showed that self-selecting rats established PE ratios larger than those considered sufficient to achieve optimal growth in adult rats (10-15%), and the ratios were highly dependent on carbohydrates, apparently with the aim of maintaining a constant and high PC ratio. This was associated with a minimization of plasma FGF21.

An eating pattern characterised by skipped or delayed breakfast is associated with mood disorders among an Australian adult cohort.

BACKGROUND: Meal timing may influence food choices, neurobiology and psychological states. Our exploratory study examined if time-of-day eating patterns were associated with mood disorders among adults. METHODS: During 2004-2006 (age 26-36 years) and 2009-2011 (follow-up, age 31-41 years), N = 1304 participants reported 24-h food and beverage intake. Time-of-day eating patterns were derived by principal components analysis. At follow-up, the Composite International Diagnostic Interview measured lifetime mood disorder. Log binomial and adjacent categories log-link regression were used to examine bidirectional associations between eating patterns and mood disorder. Covariates included sex, age, marital status, social support, education, work schedule, body mass index and smoking. RESULTS: Three patterns were derived at each time-point: Grazing (intake spread across the day), Traditional (highest intakes reflected breakfast, lunch and dinner), and Late (skipped/delayed breakfast with higher evening intakes). Compared to those in the lowest third of the respective pattern at baseline and follow-up, during the 5-year follow-up, those in the highest third of the Late pattern at both time-points had a higher prevalence of mood disorder [prevalence ratio (PR) = 2.04; 95% confidence interval (CI) 1.20-3.48], and those in the highest third of the Traditional pattern at both time-points had a lower prevalence of first onset mood disorder (PR = 0.31; 95% CI 0.11-0.87). Participants who experienced a mood disorder during follow-up had a 1.07 higher relative risk of being in a higher Late pattern score category at follow-up than those without mood disorder (95% CI 1.00-1.14). CONCLUSIONS: Non-traditional eating patterns, particularly skipped or delayed breakfast, may be associated with mood disorders.

Association of fruit and vegetable intake with meal skipping in children and adolescents: the CASPIAN-V study.

BACKGROUND: There are few studies on the association of main meal consumption with fruit and vegetable intake. This study aims to assess the relation between skipping main meals and fruit and vegetable intake in children and adolescents. METHODS: This multi-centric cross-sectional study was conducted in 30 provinces of Iran. This study was conducted in the framework of the fifth survey of a national surveillance program entitled Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable Disease study (CASPIAN- V). 14,440 school students aged 7-18 years were assessed. Logistic regression analyses were used to evaluate the association between frequency of fruit and vegetable intake with skipping main meals. RESULTS: Overall, 14,274 students completed the study (99% participation rate). Their mean (SD) age was 12.3 (3.2) (53% were aged 6-12), 50.6% of them were boys, and 71.3% lived in urban area. In multivariate logistic regression model, statistically significant associations were found between skipping main meals and low fruits and vegetables intake. Skipping breakfast was associated with vegetables intake [OR = 1.19(95% CI 1.02-1.38)] and fruits intake [OR = 5.33(95% CI 4.46-6.37)]. Skipping lunch was associated with vegetables intake [OR = 1.61(95% CI 1.29-1.96)] and fruit intake [OR = 9.11(95% CI 6.55-12.67)]. Skipping dinner was associated with vegetables intake [OR = 1.52 (95% CI 1.15-2.01)] and fruits intake [OR = 2.21(95% CI 1.64-2.97)]. CONCLUSIONS: In this study, low frequency of fruit and vegetable intake was associated with skipping main meals. The results highlight the importance of promoting regular meal consumption with increase in the intake of fruit and vegetables among children and adolescents. LEVEL OF EVIDENCE: Level V.

Unsilencing of native LepRs in hypothalamic SF1 neurons does not rescue obese phenotype in LepR-deficient mice.

Leptin receptor (LepR) signaling in neurons of the ventromedial nucleus of the hypothalamus (VMH), specifically those expressing steroidogenic factor-1 (SF1), have been proposed to play a key role in controlling energy balance. By crossing LepR-silenced (LepRloxTB) mice with those expressing SF1-Cre, we unsilenced native LepR specifically in the VMH and tested whether SF1 neurons in the VMH are critical mediators of leptin's effect on energy homeostasis. LepRloxTB × SF1-Cre [knockout (KO)/Tg+] mice were metabolically phenotyped and compared with littermate controls that either expressed or were deficient in LepRs. Leptin-induced phosphorylated STAT3 was present in the VMH of KO/Tg+ mice and absent in other hypothalamic nuclei. VMH leptin signaling did not ameliorate obesity resulting from LepR deficiency in chow-fed mice. There was no change in food intake or energy expenditure when comparing complete LepR-null mice with KO/Tg+ mice, nor did KO/Tg+ mice show improved glucose tolerance. The presence of functional LepRs in the VMH mildly enhanced sensitivity to the pancreatic hormone amylin. When maintained on a high-fat diet (HFD), there was no reduction in diet-induced obesity in KO/Tg+ mice, but KO/Tg+ mice had improved glucose tolerance after 7 wk on an HFD compared with LepR-null mice. We conclude that LepR signaling in the VMH alone is not sufficient to correct metabolic dysfunction observed in LepR-null mice.

Identifying eating habits in Finnish children: a cross-sectional study.

BACKGROUND: We aimed to identify different eating habits among Finnish children and to evaluate their association with meal patterns, breakfast consumption, and socio-demographic characteristics in a large, nationwide cohort of children. METHODS: We evaluated 10,569 children aged 9-14 years into the Finnish Health in Teens cohort in a cross-sectional design. The hierarchical K-means method was used to identify groups of children with different eating habits, based on five factors obtained through factor analysis of 10 food items. Multiple correspondence analysis was used to show associations between groups with different eating habits and meal patterns, breakfast patterns, gender, age, and language spoken at home. RESULTS: Analyses identified three groups: unhealthy eaters (12.3%), fruit and vegetable avoiders (43.3%), and healthy eaters (44.1%). Most children had regular meal and breakfast patterns. The proportion of boys was higher among unhealthy eaters. Unhealthy eaters also showed irregular meal and breakfast patterns, and had parents with low education level. There was a higher proportion of girls among healthy eaters. Healthy eaters also showed regular meal and breakfast patterns, and had parents with high education level. CONCLUSIONS: Although the number of unhealthy eaters was small, special attention should be still paid to these, mostly male children, as they have poor eating habits and they lack regular eating routine. Skipping breakfast was more common among older children and girls, although girls had healthier eating habits overall. Our results can contribute to public health efforts to improve eating behaviours, especially among children with poor eating habits and those skipping healthy food items.

Rodent models of leptin receptor deficiency are less sensitive to amylin.

The pancreatic hormone amylin is released from beta cells following nutrient ingestion and contributes to the control of body weight and glucose homeostasis. Amylin reduces food intake by activating neurons in the area postrema (AP). Amylin was also shown to synergize with the adipokine leptin, with combination therapy producing greater weight loss and food intake reduction than either hormone alone. Although amylin and leptin were initially thought to interact downstream of the AP in the hypothalamus, recent findings show that the two hormones can act on the same AP neurons, suggesting a more direct relationship. The objective of this study was to determine whether amylin action depends on functional leptin signaling. We tested the ability of amylin to induce satiation and to activate its primary target neurons in the AP in two rodent models of LepR deficiency, the db/db mouse and the Zucker diabetic fatty (ZDF) rat. When compared with wild-type (WT) mice, db/db mice exhibited reduced amylin-induced satiation, reduced amylin-induced Fos in the AP, and a lower expression of calcitonin receptor (CTR) protein, the core component of all amylin receptors. ZDF rats also showed no reduction in food intake following amylin treatment; however, unlike the db/db mice, levels of amylin-induced Fos and CTR in the AP were no different than WT rats. Our results suggest that LepR expression is required for the full anorexic effect of amylin; however, the neuronal activation in the AP seems to depend on the type of LepR mutation.

Source of dietary sucrose influences development of leptin resistance in male and female rats.

Male rats offered 30% sucrose solution in addition to chow develop leptin resistance without an increase in energy intake or body fat. This study tested whether the leptin resistance was dependent on the physical form of the sucrose. Sprague-Dawley rats were offered a sucrose-free (NS) diet, a 66.6% of energy as sucrose (HS) diet, or the NS diet + 30% sucrose solution (LS). Sucrose intake of LS rats equaled that of HS rats, but total carbohydrate intake exceeded that of HS rats. After 33 days, male and female LS rats were resistant to the inhibitory effect of peripherally administered leptin on food intake. LS rats drank small, frequent meals of sucrose during light and dark periods, whereas HS rats consumed more meals during the dark than the light period and remained responsive to leptin. Diet did not affect daily energy intake or insulin sensitivity. There was a small increase in body fat in the female rats. Leptin sensitivity was restored within 5 days of withdrawal from sucrose in male LS rats. This rapid reversal suggested that leptin resistance was associated with the metabolic impact of drinking sucrose. An experiment was carried out to test whether activity of the hexosamine biosynthetic pathway and glycation of leptin signaling proteins were increased in LS rats, but the results were equivocal. A final experiment determined that female LS rats were leptin-resistant within 18 days of access to sucrose solution and that the small, but significant, increase in body fat was associated with increased adipocyte glucose utilization and insulin responsiveness, which may have been secondary to adipocyte leptin resistance.

Mitigation of variability between competitively fed dairy cows through increased feed delivery frequency.

The objective of this study was to determine whether increased frequency of total mixed ration (TMR) delivery could mitigate the effects of feed bunk competition on the behavior and productivity of individual lactating dairy cows within a group. We hypothesized that, for competitively fed cows, a greater frequency of TMR delivery would improve access to feed, and reduce individual variability in behavior, meal patterns, and production between cows. Sixteen lactating Holstein dairy cows (first lactation = 4, second lactation = 5, ≥ third lactation = 7) averaging 72 ± 35 d in milk and producing 42 ± 6 kg of milk/d at the start of the trial, were categorized as either young (≤ second lactation) or mature (≥ third lactation) and paired to maximize difference in parity. Pairs were housed 4 at a time and competitively fed a TMR at a ratio of 2 cows:1 feed bin. Cow pairs were exposed, in a crossover design, to each of 2 feed delivery frequency treatments: low (2×/d) and high (6×/d) frequency. Treatments were applied for 10 d, with dry matter intake (DMI), feeding behavior (feeding time, feeding rate, and meal patterns), and replacement frequency for each cow recorded using an automated feed intake system on d 6 to 10 of each period. Rumination time, feed sorting, lying behavior, and productivity were also measured for this period. Variability in behavior within pairs of cows was determined by averaging the absolute difference within each pair over the recording period to provide 1 value per pair. Frequency of TMR delivery did not affect feeding time, feeding rate, DMI, replacement frequency, feed sorting, or productivity. At the high delivery frequency, there was a tendency for rumination time to increase [low = 519.3; high = 544.3 min/d; standard error of the difference (SED) = 11.32], and to be more variable within pairs (low = 38.0, high = 50.0 min/d; SED = 5.57). Cows also had longer lying bouts at the high delivery frequency (low = 53.0; high = 55.5 min/bout; SED = 1.00). No differences in daily meal patterns were found between treatments; however, the average first meal following each feeding indicated that cows under the high delivery frequency spent less time, consuming smaller meals during peak feeding periods. Comparing the young and mature individuals within each treatment pair revealed that feeding rate (young = 0.16; mature = 0.19 kg/min; SED = 0.014) and DMI (young = 25.6; mature = 28.6 kg of DM/d; SED = 1.36) were lower for the young cows on both treatments. Meal frequency was greater in young cows (young = 9.0; mature = 7.5 meals/d; SED = 0.71) and meal size was greater in mature cows (young = 3.2; mature = 4.2 kg of DM/meal; SED = 0.32) across treatments. These results suggest that for cows fed at a high level of competition, increasing TMR delivery frequency from 2 to 6×/d led to consumption of shorter, smaller meals during peak periods of feed consumption. However, under these conditions, the relative parity of competitively fed cows had a greater effect on feeding behavior, meal patterns, and production than did the frequency of feed delivery.

Effects of a daily three-meal pattern with different dietary protein contents on pig growth performance, carcass and muscle quality traits.

BACKGROUND: Recent research related to phase-feeding programmes for pig nutrition do not always account for the variation among individuals, and feeds are usually formulated to optimise the performance of the whole pig population. This study aimed at measuring the effects of a daily three-meal pattern with different dietary protein contents on pig growth performance, carcass and muscle quality traits. RESULTS: The results showed that compared with the 3C treatment, average daily gain (ADG) of pigs in the HCL treatment increased by 14.75% (P < 0.05) during period 1. The carcass weight (P = 0.006) and slaughter weight (P = 0.021) in the HCL group increased when compared with those in the 3C and LCH treatments. Moreover, the LCH feeding sequences contributed to reduce the drip loss in longissimus dorsi (LD) muscle (P < 0.05) when compared with the 3C treatment. The HCL or LCH feeding sequence contributed to increase the meat quality when compared with those receiving the 3C treatment. CONCLUSION: Collectively, our results indicate that feeding high protein meal in the morning and a gradual reduction of the protein content in meals over the day may improve muscle quality characteristics, maximise performance, and reduce the pig feed cost. © 2017 Society of Chemical Industry.

High-protein diet improves sensitivity to cholecystokinin and shifts the cecal microbiome without altering brain inflammation in diet-induced obesity in rats.

High-protein diet (HPD) curtails obesity and/or fat mass, but it is unknown whether it reverses neuroinflammation or alters glucose levels, CCK sensitivity, and gut microbiome in rats fed a Western diet (WD)-induced obesity (DIO). Male rats fed a WD (high fat and sugar) for 12 wk were switched to a HPD for 6 wk. Body composition, food intake, meal pattern, sensitivity to intraperitoneal CCK-8S, blood glucose, brain signaling, and cecal microbiota were assessed. When compared with a normal diet, WD increased body weight (9.3%) and fat mass (73.4%). CCK-8S (1.8 or 5.2 nmol/kg) did not alter food intake and meal pattern in DIO rats. Switching to a HPD for 6 wk reduced fat mass (15.7%) with a nonsignificantly reduced body weight gain, normalized blood glucose, and decreased feeding after CCK-8S. DIO rats on the WD or switched to a HPD showed comparable microbial diversity. However, in HPD versus WD rats, there was enrichment of 114 operational taxonomic units (OTUs) and depletion of 188 OTUs. Of those, Akkermansia muciniphila (enriched on a HPD), an unclassified Clostridiales, a member of the RF39 order, and a Phascolarctobacterium were significantly associated with fat mass. The WD increased cytokine expression in the hypothalamus and dorsal medulla that was unchanged by switching to HPD. These data indicate that HPD reduces body fat and restores glucose homeostasis and CCK sensitivity, while not modifying brain inflammation. In addition, expansion of cecal Akkermansia muciniphila correlated to fat mass loss may represent a potential peripheral mechanism of HPD beneficial effects.

Estradiol modulates the anorexic response to central glucagon-like peptide 1.

Estrogens suppress feeding in part by enhancing the response to satiation signals. Glucagon-like peptide 1 (GLP-1) acts on receptor populations both peripherally and centrally to affect food intake. We hypothesized that modulation of the central GLP-1 system is one of the mechanisms underlying the effects of estrogens on feeding. We assessed the anorexic effect of 0, 1, and 10µg doses of GLP-1 administered into the lateral ventricle of bilaterally ovariectomized (OVX) female rats on a cyclic regimen of either 2µg ß-estradiol-3-benzoate (EB) or oil vehicle 30min prior to dark onset on the day following hormone treatment. Central GLP-1 treatment significantly suppressed food intake in EB-treated rats at both doses compared to vehicle, whereas only the 10µg GLP-1 dose was effective in oil-treated rats. To follow up, we examined whether physiologic-dose cyclic estradiol treatment influences GLP-1-induced c-Fos in feeding-relevant brain areas of OVX females. GLP-1 significantly increased c-Fos expression in the area postrema (AP) and nucleus of the solitary tract (NTS), and the presence of estrogens may be required for this effect in the paraventricular nucleus of the hypothalamus (PVN). Together, these data suggest that modulation of the central GLP-1 system may be one of the mechanisms by which estrogens suppress food intake, and highlight the PVN as a region of interest for future investigation.

Eating frequency and weight and body composition: a systematic review of observational studies.

OBJECTIVE: The present review aimed to examine the association of eating frequency with body weight or body composition in adults of both sexes. DESIGN: PubMed, EMBASE and Scopus databases were searched. PRISMA and MOOSE protocols were followed. Observational studies published up to August 2016 were included. The methodological quality of the studies was assessed with the Downs and Black checklist. SETTING: A systematic review of the literature. SUBJECTS: Adults (n 136 052); the majority of studies were developed in the USA and Europe. RESULTS: Thirty-one articles were included in the review: two prospective and twenty-nine cross-sectional studies. Thirteen per cent of the studies received quality scores above 80 %. The assessment of eating frequency and body composition or body weight varied widely across the studies. Potential confounders were included in 73 % of the studies. Fourteen studies reported an inverse association between eating frequency and body weight or body composition, and seven studies found a positive association. The majority of studies applied multiple analyses adjusted for potential confounders, such as sex, age, education, income, smoking, physical activity and alcohol intake. Six studies took into account under-reporting of eating frequency and/or energy intake in the analysis, and one investigated the mediation effect of energy intake. CONCLUSIONS: There is not sufficient evidence confirming the association between eating frequency and body weight or body composition when misreporting bias is taken into account. However, in men, a potential protective effect of high eating frequency was observed on BMI and visceral obesity.

Energy and macronutrient intake over the course of the day of German adults: A DEDIPAC-study.

The aim of the study was to analyze the energy and macronutrient intake over the course of the day of selected population groups in Germany defined by sex, age, BMI, SES, and diet quality. The study was based on food consumption data from the German National Nutrition Survey II (2005-2007) assessed by two 4-day dietary weighing records of 662 women and men aged between 18 and 80 years. Energy and macronutrient intake were calculated using the German Nutrient Database 3.02 and summarized for the periods 'morning', 'midday', 'afternoon', 'evening', and 'night'. Generalized estimating equation models were used to examine differences in energy and macronutrient intake. For women and men, a three-main-meal pattern ('morning', 'midday', and 'evening') was observed, indicated as peaks in energy intake at 08:00 to 09:00, 13:00 and 19:00 o'clock. The distributions of carbohydrate, protein, and fat intake mirror the distribution of energy intake over the course of the day. The highest energy intake was found in the 'evening' period, especially in young adults, overweight persons, persons with a high SES, and men with a low diet quality. Women of the oldest age group showed a similar energy intake across the three-main-meals in contrast to young adults, who had lower peaks in the 'morning' and 'midday' periods as well as a shift to later meal times. Young adults seem to have a higher variability in energy intake and a less distinct meal pattern, while seniors have a more structured day. Because a high energy intake in the 'evening' period is associated with negative health-related factors, the distribution of energy intake should be considered by recommendations for a healthy nutritional behavior.

Impact of timing of feed delivery on the behavior and productivity of dairy cows.

The objective of this work was to assess the effect of timing of feed delivery on the behavior and productivity of cows milked 3 times per day. Twelve lactating Holstein dairy cows (4 primiparous and 8 multiparous), milked 3 times per day (at 1400, 2100, and 0700 h), were individually assigned and exposed to each of 2 treatments (over 21-d periods) in a replicated crossover design. Treatments were the manipulation of timing of TMR delivery, 2 times per day, in relation to milking time: (1) feeding at milking time (at 1400 and 0700 h), and (2) feeding halfway between milking times (at 1730 and 1030 h). Milk production, feeding, sorting, and rumination behavior were monitored for each animal for the last 7 d of each treatment period. Milk samples were collected for 2 of the last 4 d of each period for milk component analysis. With a feed delivery delay, dry matter intake (DMI) tended to be lower (26.5 vs. 27.2 kg/d). Although no difference was found in feeding time (224.2 min/d), cows fed with a delay consumed their feed more slowly (0.12 vs. 0.13 kg of dry matter/min) in more frequent meals (10.0 vs. 9.1 meals/d), which were smaller in size (2.8 vs. 3.1 kg/meal) and tended to be shorter in duration (26.7 vs. 30.1 min/meal). Cows fed at milking sorted for long particles (102.3%), whereas cows fed with a delay did not sort for or against those particles. Cows sorted for medium particles to a similar extent (102.5%) on each treatment. Cows did not sort for or against short particles on either treatment. Sorting against fine particles was observed, to a similar extent (97.1%), on both treatments. Rumination time (8.9 h/d) and lying time (9.5 h/d) were similar between treatments. Cows without fresh feed at the 1400 h milking tended to stand for less time following that milking (71.0 vs. 94.0 min), whereas cows without fresh feed at the 0700 h milking stood for less time following that milking (66.3 vs. 87.8 min). No difference in this latency to lie down was seen at the 2100 h milking. Milk yield (48.0 kg/d), milk fat content (3.64%), and milk protein content (2.86%) were similar between treatments. Given the tendency for a difference in DMI and no change in yield, efficiency of production was improved with a feed delay (1.93 vs. 1.80 kg of milk/kg of DMI). These data suggest that moving the timing of feed delivery resulted in cows consuming their feed more slowly in smaller, more frequent meals, contributing to an improvement in efficiency of production.