Meal frequency and timing in health and disease

Synergistic Effect of Feeding Time and Diet on Hepatic Steatosis and Gene Expression in Male Wistar Rats

OBJECTIVE

Eating out of phase with the endogenous biological clock alters clock and metabolic gene expression in rodents and can induce obesity and type 2 diabetes mellitus. Diet composition can also affect clock gene expression. This study assessed the combined effect of diet composition and feeding time on (1) body composition, (2) energy balance, and (3) circadian expression of hepatic clock and metabolic genes.

METHODS

Male Wistar rats were fed a chow or a free-choice high-fat, high-sugar (fcHFHS) diet, either ad libitum or with food access restricted to either the light or dark period. Body weight, adiposity, and hepatic fat accumulation as well as hepatic clock and metabolic mRNA expression were measured after 5 weeks of the diet. Energy expenditure was measured using calorimetric cages.

RESULTS

Animals with access to the fcHFHS diet only during the light period showed more hepatic fat accumulation than fcHFHS dark-fed animals despite less calories consumed. In contrast, within the chow-fed groups, light-fed animals showed the lowest hepatic fat content, but they also showed the lowest caloric intake. Locomotor activity and heat production followed feeding times, except in the fcHFHS light-fed group. Hepatic clock and metabolic gene expression rhythms also followed timing of food intake. Yet, in the fcHFHS light-fed animals, clock gene expression appeared 3 hours advanced compared with chow light-fed animals, an effect not observed in the fcHFHS dark-fed animals.

CONCLUSIONS

An fcHFHS diet consumed in the light period promotes hepatic fat accumulation and advances clock gene expression in male Wistar rats, likely because of a mismatch between energy intake and expenditure.

The circadian disruption of night work alters gut microbiota consistent with elevated risk for future metabolic and gastrointestinal pathology

Day and night cycles are the most important cue for the central clock of human beings, and they are also important for the gut clock. The aim of the study is to determine the differences in the gut microbiota of rotational shift workers when working the day versus night shift. Fecal samples and other data were collected from 10 volunteer male security officers after 4 weeks of day shift work (07:00-15:00 h) and also after 2 weeks of night shift work (23:00-07:00 h). In total, 20 stool samples were collected for analysis of gut microbiota (10 subjects x 2 work shifts) and stored at -80°C until analysis by 16 S rRNA sequencing. The relative abundances of Bacteroidetes were reduced and those of Actinobacteria and Firmicutes increased when working the night compared to day shift. Faecalibacterium abundance was found to be a biomarker of the day shift work. Dorea longicatena and Dorea formicigenerans were significantly more abundant in individuals when working the night shift. Rotational day and night shift work causes circadian rhythm disturbance with an associated alteration in the abundances of gut microbiota, leading to the concern that such induced alteration of gut microbiota may at least partially contribute to an increased risk of future metabolic syndrome and gastrointestinal pathology.

Emerging use of senolytics and senomorphics against aging and chronic diseases

Senescence is a state of cell cycle arrest that plays an important role in embryogenesis, wound healing and protection against cancer. Senescent cells also accumulate during aging and contribute to the development of age-related disorders and chronic diseases, such as atherosclerosis, type 2 diabetes, osteoarthritis, idiopathic pulmonary fibrosis, and liver disease. Molecules that induce apoptosis of senescent cells, such as dasatinib, quercetin, and fisetin, produce health benefits and extend lifespan in animal models. We describe here the mechanism of action of senolytics and senomorphics, many of which are derived from plants and fungi. We also discuss the possibility of using such compounds to delay aging and treat chronic diseases in humans.

Restoration of metabolic tempo through time-restricted eating (TRE) as the preventive measure for metabolic diseases

The characteristics of healthy bioenergetics are the overall balance of energy intake and expenditure, the alternate switching for different metabolic fuels, and the temporal rhythm of eating and fasting. These three bioenergetic attributes, herein, are termed as the metabolic tempo. Cumulative studies revealed the beneficial health effects of fasting. Most of the fasting regimens harness their innate mechanisms of enhancing metabolic fuel switching, thus improving metabolic flexibility. The emerging time-restricted eating (TRE) regimen includes the restoration of diurnal eating and fasting rhythms, improve the metabolic flexibility, while spontaneously reduces the food intake despite the ad-libitum eating. TRE thus simultaneously improves all three bioenergetic-tempo attributes when compared to the energy balance control in general obesity control. We reviewed fifteen human studies of TRE and TRE-liked interventions from 2007 to 2019. These studies reported promising beneficial metabolic effects on body weight, glycemic, and lipid controls while demonstrating most of the fasting-related metabolic and epigenetic responses in overweight and obese individuals. TRE is practically possible for long-termed implementation. Despite its potentials to restore the underlying dysregulated bioenergetics., there is no study confirming that TRE could prevent the development of common metabolic diseases in healthy subjects after long-term implementation. This gap of knowledge warrants future investigation.

Effects of Aging and Diet on Cardioprotection and Cardiometabolic Risk Markers

The prevalence of several diseases increases by age, including cardiovascular diseases, which are the leading cause of morbidity and mortality worldwide. Aging, as a complex process characterized by senescence, triggers various pathways, such as oxidative stress, systemic inflammation, metabolism dysfunction, telomere shortening, mitochondrial dysfunction and deregulated autophagy. A better understanding of the mechanisms underlying senescence may lead to the development of new therapeutic targets and strategies for age-related pathologies and extend the healthy lifespan. Modulating lifestyle risk factors and adopting healthy dietary patterns remain significant tools in delaying the aging process, decreasing age-associated comorbidities and mortality, increasing life expectancy and consequently, preventing the development of cardiovascular disease. Furthermore, such a strategy represents the most cost-effective approach, and the quality of life of the subjects may be significantly improved. An integrated, personalized approach targeting cardiometabolic aging and frailty is suggested in daily clinical practice. However, it should be initiated from an early age. Moreover, there is a need for further well designed and controlled studies in order to elucidate a link between the time of feeding, longevity and cardiovascular prevention. In the future, it is expected that the pharmacological treatment in cardioprotective management will be necessary, accompanied by equally important lifestyle interventions and adjunctive exercise.

Early dinner or "dinner like a pauper": Evidence, the habitual time of the largest meal of the day - dinner - is predisposing to severe COVID-19 outcome - death

COVID-19 and metabolic syndrome are devastating pandemics. Effective control of metabolic parameters and their dysfunction may help prevent or minimize the acute and devastating effects of SARS-CoV-2 by reducing the local inflammatory response and blocking the entry of the virus into cells. With such consideration in mind, we gathered data from dietary surveys conducted in nine European countries to explore the relationship between actual clock hour of the large dinner meal and also interval in minutes between it and sunset in the respective countries and death rate above the median rate of per one million people as an index of mortality due to COVID-19 infection. Clock time of the dinner meal varied between 16:00 and 21:00 h across the European counties sampled, and the correlation between dinner mealtime and death rate was strongly correlated, R = 0.7991 (two-tailed p = 0.0098), with R ² explaining 63% of the variation within the data. This strong linear positive correlation indicates that the later the clock time of the dinner meal, the higher is the death rate (and vice versa). The relationship between meal timing in reference to sunset, utilized as a gross surrogate marker of the activity/rest synchronizer of circadian rhythms, and death rate was negative and even slightly stronger, R = -0.8025 (two-tailed p = 0.0092), with R ² explaining 64% of the variation within the data. This strong linear negative correlation indicates that the shorter the interval between the dinner meal and sunset, i.e., the closer the time of the largest meal of the day to bedtime, the greater is the death rate (and vice versa). Our preliminary approach to nighttime eating, in terms of the day's largest caloric intake, as a risk factor for the predisposing conditions of obesity, metabolic syndrome, type 2 diabetes, and other commonly associated comorbidities of being overweight, and death from COVID-19 infection reveals strong correlation with the time of the dinner meal, both in terms of its actual clock and circadian time.

Metabolic switching is impaired by aging and facilitated by ketosis independent of glycogen

The ability to switch between glycolysis and ketosis promotes survival by enabling metabolism through fat oxidation during periods of fasting. Carbohydrate restriction or stress can also elicit metabolic switching. Keto-adapting from glycolysis is delayed in aged rats, but factors mediating this age-related impairment have not been identified. We measured metabolic switching between glycolysis and ketosis, as well as glycogen dynamics, in young and aged rats undergoing time-restricted feeding (TRF) with a standard diet or a low carbohydrate ketogenic diet (KD). TRF alone reversed markers of insulin-related metabolic deficits and accelerated metabolic switching in aged animals. A KD+TRF, however, provided additive benefits on these variables. Remarkably, the ability to keto-adapt was not related to glycogen levels and KD-fed rats showed an enhanced elevation in glucose following epinephrine administration. This study provides new insights into the mechanisms of keto-adaptation demonstrating the utility of dietary interventions to treat metabolic impairments across the lifespan.

Quantifying Diet Intake and Its Association with Cardiometabolic Risk in the UK Airwave Health Monitoring Study: A Data-Driven Approach

We used data-driven approaches to identify independent diet exposures among 45 candidate variables, for which we then probed cross-sectional associations with cardiometabolic risk (CMR). We derived average daily caloric intake and macronutrient composition, daily meal frequencies, and irregularity of energy and macronutrient intake from 7-day food diaries in the Airwave Health Monitoring Study participants (N = 8090). We used K-means and hierarchical clustering to identify non-redundant diet exposures with representative exposures for each cluster chosen by silhouette value. We then used multi-variable adjusted logistic regression to estimate prevalence ratios (PR) and 95% confidence intervals (95%CI) for CMR (≥3 criteria: dyslipidemia, hypertension, central adiposity, inflammation and impaired glucose control) across diet exposure quartiles. We identified four clusters: i) fat intake, ii) carbohydrate intake, iii) protein intake and intake regularity, and iv) meal frequencies and energy intake. Of these clusters, higher carbohydrate intake was associated with lower likelihood of CMR (PR = 0.89, 95%CI = 0.81–0.98; p_trend = 0.02), as was higher fiber intake (PR = 0.76, 95%CI = 0.68–0.85; p_trend < 0.001). Higher meal frequency was also associated with lower likelihood of CMR (PR = 0.76, 95%CI = 0.68–0.85; p_trend < 0.001). Our results highlight a novel, data-driven approach to select non-redundant, minimally collinear, primary exposures across a host of potentially relevant exposures (including diet composition, temporal distribution, and regularity), as often encountered in nutritional epidemiology.

Ketosis After Intake of Coconut Oil and Caprylic Acid-With and Without Glucose: A Cross-Over Study in Healthy Older Adults

Introduction: Medium-chain-triglycerides (MCT), formed by fatty acids with a length of 6-12 carbon atoms (C6-C12), constitute about two thirds of coconut oil (Coc). MCT have specific metabolic properties which has led them to be described as ketogenic even in the absence of carbohydrate restriction. This effect has mainly been demonstrated for caprylic acid (C8), which constitutes about 6-8% of coconut oil. Our aim was to quantify ketosis and blood glucose after intake of Coc and C8, with and without glucose intake. Sunflower oil (Suf) was used as control, expected to not break fasting ketosis, nor induce supply-driven ketosis. Method: In a 6-arm cross-over design, 15 healthy volunteers-age 65-73, 53% women-were tested once a week. After a 12-h fast, ketones were measured during 4 h after intake of coffee with cream, in combination with each of the intervention arms in a randomized order: 1. Suf (30 g); 2. C8 (20 g) + Suf (10 g); 3. C8 (20 g) + Suf (10 g) + Glucose (50 g); 4. Coc (30 g); 5. Coc (30 g) + Glucose (50 g); 6. C8 (20 g) + Coc (30 g). The primary outcome was absolute blood levels of the ketone β-hydroxybutyrate, area under the curve (AUC). ANOVA for repeated measures was performed to compare arms. Results: β-hydroxybutyrate, AUC/time (mean ± SD), for arms were 1: 0.18 ± 0.11; 2: 0.45 ± 0.19; 3: 0.28 ± 0.12; 4: 0.22 ± 0.12; 5: 0.08 ± 0.04; 6: 0.45 ± 0.20 (mmol/L). Differences were significant (all p ≤ 0.02), except for arm 2 vs. 6, and 4 vs. 1 & 3. Blood glucose was stable in arm 1, 2, 4, & 6, at levels slightly below baseline (p ≤ 0.05) at all timepoints hours 1-4 after intake. Conclusions: C8 had a higher ketogenic effect than the other components. Coc was not significantly different from Suf, or C8 with glucose. In addition, we report that a 16-h non-carbohydrate window contributed to a mild ketosis, while blood glucose remained stable. Our results suggest that time-restricted feeding regarding carbohydrates may optimize ketosis from intake of MCT. Clinical Trial Registration: The study was registered as a clinical trial on ClinicalTrials.gov, NCT03904433.

Sex-specific metabolic responses to 6 hours of fasting during the active phase in young mice

KEY POINTS

Night time/active phase food restriction for 6 h impaired glucose intolerance in young male and female mice. Females displayed increased capacity for lipogenesis and triglyceride storage in response to a short daily fast. Females had lower fasting insulin levels and an increased potential for utilizing fat for energy through β-oxidation compared to males. The need for the inclusion of both sexes, and the treatment of sex as an independent variable, is emphasized within the context of this fasting regime.

ABSTRACT

There is growing interest in understanding the mechanistic significance and benefits of fasting physiology in combating obesity. Increasing the fasting phase of a normal day can promote restoration and repair mechanisms that occur during the post-absorptive period. Most studies exploring the effect of restricting food access on mitigating obesity have done so with a large bias towards the use of male mice. Here, we disentangle the roles of sex, food intake and food withdrawal in the response to a short-term daily fasting intervention, in which food was removed for 6 h in the dark/active phase of young, 8-week-old mice. We showed that the removal of food during the dark phase impaired glucose tolerance in males and females, possibly due to the circadian disruption induced by this feeding protocol. Although both sexes demonstrated similar patterns of food intake, body composition and various metabolic markers, there were clear sex differences in the magnitude and extent of these responses. While females displayed enhanced capacity for lipogenesis and triglyceride storage, they also had low fasting insulin levels and an increased potential for utilizing available energy sources such as fat for energy through β-oxidation. Our results highlight the intrinsic biological and metabolic disparities between male and female mice, emphasizing the growing need for the inclusion of both sexes in scientific research. Furthermore, our results illustrate sex-specific metabolic pathways that regulate lipogenesis, obesity and overall metabolic health.

Physiological responses to maximal eating in men

This study investigated metabolic, endocrine, appetite and mood responses to a maximal eating occasion in fourteen men (mean: age 28 (sd5) years, body mass 77·2 (sd6·6) kg and BMI 24·2 (sd2·2) kg/m2) who completed two trials in a randomised crossover design. On each occasion, participants ate a homogenous mixed-macronutrient meal (pizza). On one occasion, they ate until ‘comfortably full’ (ad libitum) and on the other, until they ‘could not eat another bite’ (maximal). Mean energy intake was double in the maximal (13 024 (95 % CI 10 964, 15 084) kJ; 3113 (95 % CI 2620, 3605) kcal) compared with thead libitumtrial (6627 (95 % CI 5708, 7547) kJ; 1584 (95 % CI 1364, 1804) kcal). Serum insulin incremental AUC (iAUC) increased approximately 1·5-fold in the maximal compared withad libitumtrial (mean:ad libitum43·8 (95 % CI 28·3, 59·3) nmol/l × 240 min and maximal 67·7 (95 % CI 47·0, 88·5) nmol/l × 240 min,P< 0·01), but glucose iAUC did not differ between trials (ad libitum94·3 (95 % CI 30·3, 158·2) mmol/l × 240 min and maximal 126·5 (95 % CI 76·9, 176·0) mmol/l × 240 min,P= 0·19). TAG iAUC was approximately 1·5-fold greater in the maximalv.ad libitumtrial (ad libitum98·6 (95 % CI 69·9, 127·2) mmol/l × 240 min and maximal 146·4 (95 % CI 88·6, 204·1) mmol/l × 240 min,P< 0·01). Total glucagon-like peptide-1, glucose-dependent insulinotropic peptide and peptide tyrosine–tyrosine iAUC were greater in the maximal compared withad libitumtrial (P< 0·05). Total ghrelin concentrations decreased to a similar extent, but AUC was slightly lower in the maximalv.ad libitumtrial (P= 0·02). There were marked differences on appetite and mood between trials, most notably maximal eating caused a prolonged increase in lethargy. Healthy men have the capacity to eat twice the energy content required to achieve comfortable fullness at a single meal. Postprandial glycaemia is well regulated following initial overeating, with elevated postprandial insulinaemia probably contributing.

Effects of Shift Work on the Eating Behavior of Police Officers on Patrol

Recent studies indicate that the timing of food intake can significantly affect metabolism and weight management. Workers operating at atypical times of the 24-h day are at risk of disturbed feeding patterns. Given the increased risk of weight gain, obesity and metabolic syndrome in shift working populations, further research is required to understand whether their eating behavior could contribute to these increased metabolic risks. The objective of this study was to characterize the dietary patterns of police officers across different types of shifts in their natural environments. Thirty-one police officers (six women; aged 32.1 ± 5.4 years, mean ± SD) from the province of Quebec, Canada, participated in a 28- to 35-day study, comprising 9- to 12-h morning, evening, and night shifts alternating with rest days. Sleep and work patterns were recorded with actigraphy and diaries. For at least 24 h during each type of work day and rest day, participants logged nutrient intake by timestamped photographs on smartphones. Macronutrient composition and caloric content were estimated by registered dieticians using the Nutrition Data System for Research database. Data were analyzed with linear mixed effects models and circular ANOVA. More calories were consumed relative to individual metabolic requirements on rest days than both evening- and night-shift days (p = 0.001), largely sourced from increased fat (p = 0.004) and carbohydrate (trend, p = 0.064) intake. Regardless, the proportions of calories from carbohydrates, fat, and protein did not differ significantly between days. More calories were consumed during the night, between 2300 h and 0600 h, on night-shift days than any other days (p < 0.001). Caloric intake occurred significantly later for night-shift days (2308 h ± 0114 h, circular mean ± SD) than for rest days (1525 h ± 0029 h; p < 0.01) and was dispersed across a longer eating window (13.9 h ± 3.1 h vs. 11.3 h ± 1.8 h, mean ± SD). As macronutrient proportions were similar and caloric intake was lower, the finding of later meals times on night-shift days versus rest days is consistent with emerging hypotheses that implicate the biological timing of food intake—rather than its quantity or composition—as the differentiating dietary factor in shift worker health.

"Circadian misalignment and the gut microbiome. A bidirectional relationship triggering inflammation and metabolic disorders"- a literature review

Over the last decade, emerging studies have related the gut microbiome and gut dysbiosis to sleep and sleep disorders. For example, intermittent hypoxia associated with obstructive sleep apnea was shown to reproducibly alter the gut microbiome. Circadian rhythm disorders (CRD) (eg, shift work disorders, delayed sleep phase syndrome, and advanced sleep phase syndrome) constitute another group of conditions that might be influenced by gut dysbiosis. Indeed, both central and peripheral clocks can affect and be affected by gut microbiota and their metabolites. In addition, the tight rhythmic regulation of almost all metabolic pathways involved in the anabolism and catabolism of carbohydrates, protein, and lipids in addition to detoxification processes that take place in specific cells could be ultimately linked to changes in the microbiota. Since there are no studies to date examining the impact of gut dysbiosis on delayed sleep phase and advanced sleep phase syndrome, and considering the ever-increasing number of people engaging in shift work, more accurate and informed delineation of the association between gut dysbiosis and shift work can provide guidance and opportunities for new avenues of treating circadian rhythm disorders and preventing the metabolic complications of shiftwork via restoration of gut dysbiosis. In this review, the potential bidirectional relationships between gut dysbiosis and circadian rhythm misalignment, their impact on different metabolic pathways, and the potential development of metabolic and systemic disorders, especially in shift work models are critically assessed.

Self-initiated lifestyle interventions lead to potential insight into an effective, alternative, non-surgical therapy for mitochondrial disease associated multiple symmetric lipomatosis

BACKGROUND

A 56-year-old female, diagnosed as a carrier of the mitochondrial DNA mutation (MTTK c.8344A > G) associated with the MERRF (myoclonic epilepsy with ragged red fibers) syndrome, presented with a relatively uncommon but well-known phenotypic manifestation: severe multiple symmetric lipomatosis (MSL). After surgical resection of three kilograms of upper mid-back lipomatous tissue, the patient experienced a significant decline in her functional capacity and quality of life, which ultimately resulted in her placement on long-term disability.

METHODS

Dissatisfied with the available treatment options centered on additional resection surgeries, given the high probability of lipoma regrowth, the patient independently researched and applied alternative therapies that centred on a carbohydrate-restricted diet and a supervised exercise program.

RESULTS

The cumulative effect of her lifestyle interventions resulted in the reversal of her MSL and her previously low quality of life. She met all her personal goals by the one-year mark, including reduced size of the residual post-surgical lipomas, markedly enhanced exercise tolerance, and return to work. She continues to maintain her interventions and to experience positive outcomes at the two-year mark.

INTERPRETATION

This case report documents the timing and nature of lifestyle interventions in relation to the reversal in growth pattern of her previously expanding and debilitating lipomas. The profound nature of the apparent benefit on lipoma growth demonstrates the intervention's potential as a new feasible non-surgical therapy for mitochondrial-disease-associated MSL, and justifies its systematic study. We also describe how this case has inspired the care team to re-examine its approach to involved patients.

Determinants of Adherence in Time-Restricted Feeding in Older Adults: Lessons from a Pilot Study

Time-restricted feeding (TRF) is a type of intermittent fasting in which no calories are commonly consumed for approximately 12-18 hours on a daily basis. The health benefits of this eating pattern have been shown in overweight adults, with improvements in cardiometabolic risk factors as well as the preservation of lean mass during weight loss. Although TRF has been well studied in younger and middle-aged adults, few studies have evaluated the effects of TRF in older adults. Thus, the goal of this study was to evaluate older-adult perspectives regarding the real-world advantages, disadvantages, and challenges to adopting a TRF eating pattern among participants aged 65 and over. A four-week single-arm pre- and post-test design was used for this clinical pilot trial TRF intervention study. Participants were instructed to fast for approximately 16 h per day with the daily target range between 14 and 18 h. Participants were provided with the TRF protocol at a baseline visit, along with a pictorial guide that depicted food items and beverages that were allowed and not allowed during fasting windows to reinforce that calorie-containing items were to be avoided. The trial interventionist called each participant weekly to promote adherence, review the protocol, monitor for adverse events, and provide support and guidance for any challenges faced during the intervention. Participants were instructed to complete daily eating time logs by recording the times at which they first consumed calories and when they stopped consuming calories. At the end of the intervention, participants completed an exit interview and a study-specific Diet Satisfaction Survey (Table 1) to assess their satisfaction, feasibility, and overall experience with the study intervention. Of the 10 participants who commenced the study (mean age = 77.1 y; 6 women, 4 men), nine completed the entire protocol. Seven of the ten participants reported easy adjustment to a 16-hour fast and rated the difference from normal eating patterns as minimal. Eight participants reported no decrease in energy during fasting periods, with greater self-reported activity levels in yardwork and light exercise. Adverse events were rare, and included transient headaches, which dissipated with increased water intake, and dizziness in one participant, which subsided with a small snack. The findings of the current trial suggest that TRF is an eating approach that is well tolerated by most older adults. Six participants, however, did not fully understand the requirements of the fasting regimen, despite being provided with specific instructions and a pictorial guide at a baseline visit. This suggests that more instruction and/or participant contact is needed in the early stages of a TRF intervention to promote adherence.

Eating behavior affects cardio-metabolic risk in high school teenagers in a developing country

BACKGROUND Modernization negatively changes lifestyle, characterized by excessive eating and reduced energy consumption, and concurrently increases the cardiometabolic risk. This study was aimed to evaluate the association between eating behavior and cardio-metabolic risk factors including body mass index (BMI) in percentile, blood pressure (BP) in percentile, waist circumference, and heart rate in total subjects and gender sub-groups. METHODS This analytical cross-sectional study was done from July to November 2018. High schools in four provinces of Indonesia and students were selected using purposive sampling. Subjects’ profiles were collected from interview and cardio-metabolic parameters were measured at the study sites. Data were analyzed with chi-square and independent t-test. RESULTS Subjects who were overweight/obese and had high BP accounted for 27.1% and 9.3–12.0% of the total subjects (n = 768), respectively. Subjects who having breakfast tended to have lower BMI (p = 0.006), and the lower consumption of western meals had lower heart rate (p = 0.02). Male subjects had more meal frequency and had less quantity of snacks than female subjects (p<0.001). Male subjects with routine intake of vegetables had low heart rate (p = 0.03). Female subjects with routine breakfast had better BMI (p<0.001), and lower diastolic BP (p = 0.004) and waist circumference (p = 0.02), whereas those who consumed Western meals had higher heart rate (p = 0.046) and waist circumference (p = 0.001). CONCLUSIONS Eating behaviors are likely to affect cardio-metabolic risk factors, and the effects vary within gender groups.

Meal Patterns and Changes in Cardiometabolic Risk Factors in Children: A Longitudinal Analysis

We examined whether energy and macronutrient intake from different meals was associated with changes in cardiometabolic risk (CMR) factors in children. CMR score (CMRS) was computed by summing Z-scores of waist circumference, the average of systolic and diastolic blood pressure, fasting glucose, high-density lipoprotein cholesterol (multiplying by −1), and triglycerides. We included 5517 children aged 6–13 years from six major cities in China. Five meal patterns were identified according to energy intake: balanced, breakfast dominant, lunch dominant, dinner dominant, and snack dominant patterns. These patterns were not significantly associated with changes in CMR factors. Carbohydrate intake (% energy) at lunch was positively associated with the change in CMRS (beta coefficient (95% CI): (0.777 (0.509, 1.046) in quintile 5 versus quintile 1). A positive association between carbohydrate intake at dinner and change in CMRS was observed. High protein intake at both lunch and dinner was associated with a favorable change in CMRS. Moderate fat intake at lunch was associated with a lower increase in CMRS. Meal patterns driven by energy were not significantly associated with CMR factors; however, a low carbohydrate-high protein-moderate fat lunch and low carbohydrate-high protein dinner were associated with favorable changes in CMRS in children.

Measuring Caenorhabditis elegans Spatial Foraging and Food Intake Using Bioluminescent Bacteria

For most animals, feeding includes two behaviors: foraging to find a food patch and food intake once a patch is found. The nematode Caenorhabditis elegans is a useful model for studying the genetics of both behaviors. However, most methods of measuring feeding in worms quantify either foraging behavior or food intake, but not both. Imaging the depletion of fluorescently labeled bacteria provides information on both the distribution and amount of consumption, but even after patch exhaustion a prominent background signal remains, which complicates quantification. Here, we used a bioluminescent Escherichia coli strain to quantify C. elegans feeding. With light emission tightly coupled to active metabolism, only living bacteria are capable of bioluminescence, so the signal is lost upon ingestion. We quantified the loss of bioluminescence using N2 reference worms and eat-2 mutants, and found a nearly 100-fold increase in signal-to-background ratio and lower background compared to loss of fluorescence. We also quantified feeding using aggregating npr-1 mutant worms. We found that groups of npr-1 mutants first clear bacteria from within the cluster before foraging collectively for more food; similarly, during large population swarming, only worms at the migrating front are in contact with bacteria. These results demonstrate the usefulness of bioluminescent bacteria for quantifying feeding and generating insights into the spatial pattern of food consumption.

Melatonin Effects on Glucose Metabolism: Time To Unlock the Controversy

The past decade has witnessed a revival of interest in the hormone melatonin, partly attributable to the discovery that genetic variation in MTNR1B - the melatonin receptor gene - is a risk factor for impaired fasting glucose and type 2 diabetes (T2D). Despite intensive investigation, there is considerable confusion and seemingly conflicting data on the metabolic effects of melatonin and MTNR1B variation, and disagreement on whether melatonin is metabolically beneficial or deleterious, a crucial issue for melatonin agonist/antagonist drug development and dosing time. We provide a conceptual framework - anchored in the dimension of 'time' - to reconcile paradoxical findings in the literature. We propose that the relative timing between elevated melatonin concentrations and glycemic challenge should be considered to better understand the mechanisms and therapeutic opportunities of melatonin signaling in glycemic health and disease.

Metabolic Reprogramming in Autosomal Dominant Polycystic Kidney Disease: Evidence and Therapeutic Potential

Autosomal dominant polycystic kidney disease is characterized by progressive development and enlargement of kidney cysts, leading to ESKD. Because the kidneys are under high metabolic demand, it is not surprising that mounting evidence suggests that a metabolic defect exists in in vitro and animal models of autosomal dominant polycystic kidney disease, which likely contributes to cystic epithelial proliferation and subsequent cyst growth. Alterations include defective glucose metabolism (reprogramming to favor aerobic glycolysis), dysregulated lipid and amino acid metabolism, impaired autophagy, and mitochondrial dysfunction. Limited evidence supports that cellular kidney metabolism is also dysregulated in humans with autosomal dominant polycystic kidney disease. There are notable overlapping features and pathways among metabolism, obesity, and/or autosomal dominant polycystic kidney disease. Both dietary and pharmacologic-based strategies targeting metabolic abnormalities are being considered as therapies to slow autosomal dominant polycystic kidney disease progression and are attractive, particularly given the slowly progressive nature of the disease. Dietary strategies include daily caloric restriction, intermittent fasting, time-restricted feeding, a ketogenic diet, and 2-deoxy-glucose as well as alterations to nutrient availability. Pharmacologic-based strategies include AMP-activated kinase activators, sodium glucose cotransporter-2 inhibitors, niacinamide, and thiazolidenediones. The results from initial clinical trials targeting metabolism are upcoming and anxiously awaited within the scientific and polycystic kidney disease communities. There continues to be a need for additional mechanistic studies to better understand the role of dysregulated metabolism in autosomal dominant polycystic kidney disease and for subsequent translation to clinical trials. Beyond single-intervention trials focused on metabolic reprograming in autosomal dominant polycystic kidney disease, great potential also exists by combining metabolic-focused therapeutic approaches with compounds targeting other signaling cascades altered in autosomal dominant polycystic kidney disease, such as tolvaptan.

High sleep variability predicts a blunted weight loss response and short sleep duration a reduced decrease in waist circumference in the PREDIMED-Plus Trial

BACKGROUND

Whether short sleep duration or high sleep variability may predict less weight loss and reduction in measures of adiposity in response to lifestyle interventions is unknown. The aim of this study was to compare the 12-month changes in weight and adiposity measures between those participants with short or adequate sleep duration and those with low or high sleep variability (intra-subject standard deviation of the sleep duration) in PREvención con DIeta MEDiterránea (PREDIMED)-Plus, a primary prevention trial based on lifestyle intervention programs.

METHODS

Prospective analysis of 1986 community-dwelling subjects (mean age 65 years, 47% females) with overweight/obesity and metabolic syndrome from the PREDIMED-Plus trial was conducted. Accelerometry-derived sleep duration and sleep variability and changes in average weight, body mass index (BMI), and waist circumference (WC) attained after 12-month interventions were analyzed.

RESULTS

The adjusted difference in 12-month changes in weight and BMI in participants in the third tertile of sleep variability was 0.5 kg (95% CI 0.1 to 0.9; p = 0.021) and 0.2 kg/m2 (0.04 to 0.4; p = 0.015), respectively, as compared with participants in the first tertile. The adjusted difference in 12-month changes from baseline in WC was -0.8 cm (-1.5 to -0.01; p = 0.048) in participants sleeping <6 h, compared with those sleeping between 7 and 9 h.

CONCLUSIONS

Our findings suggest that the less variability in sleep duration or an adequate sleep duration the greater the success of the lifestyle interventions in adiposity.

The relationship between host circadian rhythms and intestinal microbiota: A new cue to improve health by tea polyphenols

Under the control of the host circadian rhythms, intestinal microbiota undergoes dietary-dependent diurnal fluctuations in composition and function. In addition, microbiome plays a critical role in maintaining the host circadian rhythms and metabolic homeostasis. The interactions between host circadian rhythms and intestinal microbiota suggest that intervention with prebiotics or probiotic is a possible way to alleviate circadian rhythm misalignment and related metabolic diseases. This review discusses the circadian rhythm oscillations of gut flora, relationship between host circadian rhythms and microbiome and related effects on metabolism. The influence on circadian rhythms by the interactions between tea polyphenols (TP) and intestinal microbiota is highlighted.

The Effects of Meal Timing and Frequency, Caloric Restriction, and Fasting on Cardiovascular Health: an Overview

Cardiovascular disease (CVD), which is the leading cause of death worldwide, is strongly affected by diet. Diet can affect CVD directly by modulating the composition of vascular plaques, and indirectly by affecting the rate of aging. This review summarizes research on the relationships of fasting, meal timing, and meal frequency with CVD incidence and progression. Relevant basic research studies, epidemiological studies, and clinical studies are highlighted. In particular, we discuss both intermittent and periodic fasting interventions with the potential to prevent and treat CVD.

Disruption in daily eating-fasting and activity-rest cycles in Indian adolescents attending school

A lifestyle with erratic eating patterns and habits predisposes youngsters to obesity. Through a two-phase feasibility study among Indian students living in the Delhi area, we longitudinally examined the following: (1) the daily eating-fasting cycles of students (N = 34) in school and college using smartphones as they transition from high school (aged 13–15 years; n_IX = 13) to higher secondary school (HSSS; 16–18 years; n_XII = 9) to their first year (FY) of college (18–19 years; n_FC = 12); and (2) daily activity-rest cycles and light-dark exposure of 31 higher secondary school students (HSSS) using actigraphy. In phase 1, students’ food data were analyzed for temporal details of eating events and observable differences in diet composition, such as an energy-dense diet (fast food (FF)), as confounding factors of circadian health. Overall, the mean eating duration in high school, higher secondary and FY college students ranged from 14.1 to 16.2h. HSSS exhibited the shortest night fasting. Although FY college students exhibited the highest fast food percentage (FF%), a positive correlation between body mass index (BMI) and FF% was observed only among HSSS. Furthermore, the body weight of HSSS was significantly higher, indicating that FF, untimely eating and reduced night fasting were important obesity-associated factors in adolescents. Reduced night fasting duration was also related to shorter sleep in HSSS. Therefore, food data were supplemented with wrist actigraphy, i.e., activity-rest data, in HSSS. Actigraphy externally validated the increased obesogenic consequences of deregulated eating rhythms in HSSS. CamNtech motion watches were used to assess the relationship between disturbed activity cycles of HSSS and other circadian clock-related rhythms, such as sleep. Less than 50% of Indian HSSS slept 6 hours or more per night. Seven of 31 students remained awake throughout the night, during which they had more than 20% of their daily light exposure. Three nonparametric circadian rhythm analysis (NPCRA) variables revealed circadian disruption of activity in HSSS. The present study suggests that inappropriate timing and quality of food and sleep disturbances are important determinants of circadian disruptions in adolescents attending school.

Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome

In animal models, time-restricted feeding (TRF) can prevent and reverse aspects of metabolic diseases. Time-restricted eating (TRE) in human pilot studies reduces the risks of metabolic diseases in otherwise healthy individuals. However, patients with diagnosed metabolic syndrome often undergo pharmacotherapy, and it has never been tested whether TRE can act synergistically with pharmacotherapy in animal models or humans. In a single-arm, paired-sample trial, 19 participants with metabolic syndrome and a baseline mean daily eating window of ≥14 h, the majority of whom were on a statin and/or antihypertensive therapy, underwent 10 h of TRE (all dietary intake within a consistent self-selected 10 h window) for 12 weeks. We found this TRE intervention improves cardiometabolic health for patients with metabolic syndrome receiving standard medical care including high rates of statin and anti-hypertensive use. TRE is a potentially powerful lifestyle intervention that can be added to standard medical practice to treat metabolic syndrome. VIDEO ABSTRACT.

Resetting the Aging Clock: Implications for Managing Age-Related Diseases

Worldwide, individuals are living longer due to medical and scientific advances, increased availability of medical care and changes in public health policies. Consequently, increasing attention has been focused on managing chronic conditions and age-related diseases to ensure healthy aging. The endogenous circadian system regulates molecular, physiological and behavioral rhythms orchestrating functional coordination and processes across tissues and organs. Circadian disruption or desynchronization of circadian oscillators increases disease risk and appears to accelerate aging. Reciprocally, aging weakens circadian function aggravating age-related diseases and pathologies. In this review, we summarize the molecular composition and structural organization of the circadian system in mammals and humans, and evaluate the technological and societal factors contributing to the increasing incidence of circadian disorders. Furthermore, we discuss the adverse effects of circadian dysfunction on aging and longevity and the bidirectional interactions through which aging affects circadian function using examples from mammalian research models and humans. Additionally, we review promising methods for managing healthy aging through behavioral and pharmacological reinforcement of the circadian system. Understanding age-related changes in the circadian clock and minimizing circadian dysfunction may be crucial components to promote healthy aging.

U.S. obesity as delayed effect of excess sugar

In the last century, U.S. diets were transformed, including the addition of sugars to industrially-processed foods. While excess sugar has often been implicated in the dramatic increase in U.S. adult obesity over the past 30 years, an unexplained question is why the increase in obesity took place many years after the increases in U.S. sugar consumption. To address this, here we explain adult obesity increase as the cumulative effect of increased sugar calories consumed over time. In our model, which uses annual data on U.S. sugar consumption as the input variable, each age cohort inherits the obesity rate in the previous year plus a simple function of the mean excess sugar consumed in the current year. This simple model replicates three aspects of the data: (a) the delayed timing and magnitude of the increase in average U.S. adult obesity (from about 15% in 1970 to almost 40% by 2015); (b) the increase of obesity rates by age group (reaching 47% obesity by age 50) for the year 2015 in a well-documented U.S. state; and (c) the pre-adult increase of obesity rates by several percent from 1988 to the mid-2000s, and subsequent modest decline in obesity rates among younger children since the mid-2000s. Under this model, the sharp rise in adult obesity after 1990 reflects the delayed effects of added sugar calories consumed among children of the 1970s and 1980s.

Healthy Eating, Physical Activity, and Sleep Hygiene (HEPAS) as the Winning Triad for Sustaining Physical and Mental Health in Patients at Risk for or with Neuropsychiatric Disorders: Considerations for Clinical Practice

Neuropsychiatric disorders stem from gene-environment interaction and their development can be, at least in some cases, prevented by the adoption of healthy and protective lifestyles. Once full blown, neuropsychiatric disorders are prevalent conditions that patients live with a great burden of disability. Indeed, the determinants that increase the affliction of neuropsychiatric disorders are various, with unhealthy lifestyles providing a significant contribution in the interplay between genetic, epigenetic, and environmental factors that ultimately represent the pathophysiological basis of these impairing conditions. On one hand, the adoption of Healthy Eating education, Physical Activity programs, and Sleep hygiene promotion (HEPAS) has the potential to become one of the most suitable interventions to reduce the risk to develop neuropsychiatric disorders, while, on the other hand, its integration with pharmacological and psychological therapies seems to be essential in the overall management of neuropsychiatric disorders in order to reduce the disability and improve the quality of life of affected patients. We present an overview of the current evidence in relation to HEPAS components in the prevention and management of neuropsychiatric disorders and provide suggestions for clinical practice.

Dietary Restriction and Epigenetics: Part I

Biological aging occurs concomitantly with chronological aging and is commonly burdened by the development of age-related conditions, such as neurodegenerative, cardiovascular, and a myriad of metabolic diseases. With a current global shift in disease epidemiology associated with aging and the resultant social, economic, and healthcare burdens faced by many countries, the need to achieve successful aging has fueled efforts to address this problem. Aging is a complex biological phenomenon that has confounded much of the historical research effort to understand it, with still limited knowledge of the underlying molecular mechanisms. Interestingly, dietary restriction (DR) is one intervention that produces anti-aging effects from simple organisms to mammals. Research into DR has revealed robust systemic effects that can result in attenuation of age-related diseases via a myriad of molecular mechanisms. Given that numerous age-associated diseases are often polygenic and affect individuals differently, it is possible that they are confounded by interactions between environmental influences and the genome, a process termed 'epigenetics'. In part one of the review, we summarize the different variants of DR regimens and their corresponding mechanism(s) and resultant effects, as well as in-depth analysis of current knowledge of the epigenetic landscape.

Higher eating frequency, but not skipping breakfast, is associated with higher odds of abdominal obesity in adults living in Puerto Rico

Puerto Ricans have a high prevalence of obesity, yet little information is available regarding its association with eating patterns in this population. We hypothesized that higher eating frequency and skipping breakfast would be associated with increased odds of abdominal obesity among adults living in Puerto Rico (PR). In a cross-sectional study of adults living in PR aged 30-75 years (N = 310), participants reported their frequency of eating meals per day including snacks and breakfast. Trained interviewers measured waist (WC) and hip circumferences. We calculated the waist-to-hip ratio (WHR) dividing the waist by the hip measurement. Abdominal obesity was defined as either high WC (men ≥94 cm; women ≥80 cm) or high WHR (men ≥0.90; women ≥0.85). We used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) to assess the association of eating frequency (≤1.5; 1.5-3; ≥3 times/day) and breakfast consumption (vs none) with abdominal obesity. Models were adjusted for age, sex, income, smoking, physical activity, TV watching, energy intake, diet quality, and eating frequency (only for breakfast consumption). Most participants consumed breakfast (70%), ate 1.5-3 times/d (47%), and had high WC (75%) and WHR (77%). Participants who ate 1.5-3 (OR: 2.75, 95% CI: 1.23-6.15) and ≥3 times/day (OR: 2.88; 95% CI: 1.14-7.31) were more likely to have high WC compared with participants who ate ≤1.5 times/d (P trend = .04). Breakfast consumption was not associated with abdominal obesity. In conclusion, higher eating frequency, but not skipping breakfast, is associated with abdominal obesity among adults in PR. Consuming less frequent meals may help prevent abdominal obesity in this population.

A circadian output center controlling feeding:fasting rhythms in Drosophila

Circadian rhythms allow animals to coordinate behavioral and physiological processes with respect to one another and to synchronize these processes to external environmental cycles. In most animals, circadian rhythms are produced by core clock neurons in the brain that generate and transmit time-of-day signals to downstream tissues, driving overt rhythms. The neuronal pathways controlling clock outputs, however, are not well understood. Furthermore, it is unclear how the central clock modulates multiple distinct circadian outputs. Identifying the cellular components and neuronal circuitry underlying circadian regulation is increasingly recognized as a critical step in the effort to address health pathologies linked to circadian disruption, including heart disease and metabolic disorders. Here, building on the conserved components of circadian and metabolic systems in mammals and Drosophila melanogaster, we used a recently developed feeding monitor to characterize the contribution to circadian feeding rhythms of two key neuronal populations in the Drosophila pars intercerebralis (PI), which is functionally homologous to the mammalian hypothalamus. We demonstrate that thermogenetic manipulations of PI neurons expressing the neuropeptide SIFamide (SIFa) as well as mutations of the SIFa gene degrade feeding:fasting rhythms. In contrast, manipulations of a nearby population of PI neurons that express the Drosophila insulin-like peptides (DILPs) affect total food consumption but leave feeding rhythms intact. The distinct contribution of these two PI cell populations to feeding is accompanied by vastly different neuronal connectivity as determined by trans-Tango synaptic mapping. These results for the first time identify a non-clock cell neuronal population in Drosophila that regulates feeding rhythms and furthermore demonstrate dissociable control of circadian and homeostatic aspects of feeding regulation by molecularly-defined neurons in a putative circadian output hub.

Timing of Breakfast, Lunch, and Dinner. Effects on Obesity and Metabolic Risk

(1) Background: Eating is fundamental to survival. Animals choose when to eat depending on food availability. The timing of eating can synchronize different organs and tissues that are related to food digestion, absorption, or metabolism, such as the stomach, gut, liver, pancreas, or adipose tissue. Studies performed in experimental animal models suggest that food intake is a major external synchronizer of peripheral clocks. Therefore, the timing of eating may be decisive in fat accumulation and mobilization and affect the effectiveness of weight loss treatments. (2) Results: We will review multiple studies about the timing of the three main meals of the day, breakfast, lunch and dinner, and its potential impact on metabolism, glucose tolerance, and obesity-related factors. We will also delve into several mechanisms that may be implicated in the obesogenic effect of eating late. Conclusion: Unusual eating time can produce a disruption in the circadian system that might lead to unhealthy consequences.

Eating Style and the Frequency, Size and Timing of Eating Occasions: A cross-sectional analysis using 7-day weighed dietary records

The tendencies to overeat in response to negative emotions (emotional eating) and environmental cues (external eating) have both been associated with BMI. However, it is unclear how they are expressed at the eating architecture level, for example, respecting frequency, timing and size of eating occasions, which could comprise 'downstream' specific behavioural intervention targets. In our analyses of the UK National Diet and Nutrition Survey 2000-2001, a 1-unit higher emotional eating score was associated with meals containing approximately 15 (3, 26) fewer kcals per occasion, consuming 1.4 (0.5, 2.3) more snacks per week and snacking over a 35- (16, 53) minute longer period a day. A 1-unit higher external eating score was associated with snacking over a 24- (1, 46) minute shorter period a day. Associations were independent of BMI and other potential confounders. The distinct pattern of eating architecture associated with emotional eating, suggests specific approaches to intervention, such as the number, timing and caloric content of snacks, could be considered further in experimental studies for their potential to prevent weight gain in people with a higher emotional eating tendency. Longitudinal studies and better measurement are also needed to strengthen causal inference in terms of the downstream effects of eating styles.

Four nights of sleep restriction suppress the postprandial lipemic response and decrease satiety

Chronic sleep restriction, or inadequate sleep, is associated with increased risk of cardiometabolic disease. Laboratory studies demonstrate that sleep restriction causes impaired whole-body insulin sensitivity and glucose disposal. Evidence suggests that inadequate sleep also impairs adipose tissue insulin sensitivity and the NEFA rebound during intravenous glucose tolerance tests, yet no studies have examined the effects of sleep restriction on high-fat meal lipemia. We assessed the effect of 5 h time in bed (TIB) per night for four consecutive nights on postprandial lipemia following a standardized high-fat dinner (HFD). Furthermore, we assessed whether one night of recovery sleep (10 h TIB) was sufficient to restore postprandial metabolism to baseline. We found that postprandial triglyceride (TG) area under the curve was suppressed by sleep restriction (P = 0.01), but returned to baseline values following one night of recovery. Sleep restriction decreased NEFAs throughout the HFD (P = 0.02) and NEFAs remained suppressed in the recovery condition (P = 0.04). Sleep restriction also decreased participant-reported fullness or satiety (P = 0.03), and decreased postprandial interleukin-6 (P < 0.01). Our findings indicate that four nights of 5 h TIB per night impair postprandial lipemia and that one night of recovery sleep may be adequate for recovery of TG metabolism, but not for markers of adipocyte function.

Alternate-Day Fasting Gets a Safe Bill of Health

Various forms of fasting improve health and longevity in preclinical models. However, safety, outcomes, and the molecular changes underpinning human fasting are unclear. Stekovic et al. (2019) report improved markers of health for up to 6 months and associated metabolic changes among healthy adults who followed alternate-day fasting.

Meal timing and obesity: interactions with macronutrient intake and chronotype

BACKGROUND

Timing of dietary intake may play a role in obesity. However, previous studies produced mixed findings possibly due to inconsistent approaches to characterize meal timing and not taking into account chronotype and macronutrients. To address the aforementioned limitations, we have defined meal timing relative to sleep/wake timing, investigated the relationship between meal timing and body mass index (BMI) dependent on chronotype, and examined the associations.

METHODS

BMI, chronotype, and dietary intakes were measured in 872 middle-to-older-aged adults by six 24-h dietary recalls in 1 year. We defined four time windows of intake relative to sleep timing: morning (within 2 h after getting out of bed), night (within 2 h before bedtime), and two midday periods in between (split by the midpoint of the waking period).

RESULTS

A higher percent of total daily energy intake consumed during the morning window was associated with lower odds of being overweight or obese (odds ratio (95% confidence intervals), 0.53 (0.31, 0.89)). This association was stronger in people with an earlier chronotype (0.32 (0.16, 0.66)). A higher percent of total daily energy intake consumed during the night window was associated with higher odds of being overweight or obese (1.82 (1.07, 3.08)), particularly in people with a later chronotype (4.94 (1.61, 15.14)). These associations were stronger for the intakes of carbohydrates and protein than for fat intake.

CONCLUSION

Our study suggests that higher dietary consumption after waking up and lower consumption close to bedtime associate with lower BMI, but the relationship differs by chronotype. Furthermore, the data demonstrate a clear relationship between the timing of carbohydrate and protein intake and obesity. Our findings highlight the importance of considering timing of intake relative to sleep timing when studying the associations of meal timing with obesity and metabolic health.

Interventions to promote cardiometabolic health and slow cardiovascular ageing

Cardiovascular ageing and the atherosclerotic process begin very early in life, most likely in utero. They progress over decades of exposure to suboptimal or abnormal metabolic and hormonal risk factors, eventually culminating in very common, costly, and mostly preventable target-organ pathologies, including coronary heart disease, stroke, heart failure, aortic aneurysm, peripheral artery disease, and vascular dementia. In this Review, we discuss findings from preclinical and clinical studies showing that calorie restriction (CR), intermittent fasting, and adjusted diurnal rhythm of feeding, with adequate intake of specific macronutrients and micronutrients, are powerful interventions not only for the prevention of cardiovascular disease but also for slowing the accumulation of molecular damage leading to cardiometabolic dysfunction. Furthermore, we discuss the mechanisms through which a number of other nondietary interventions, such as regular physical activity, mindfulness-based stress-reduction exercises, and some CR-mimetic drugs that target pro-ageing pathways, can potentiate the beneficial effects of a healthy diet in promoting cardiometabolic health.

Genome-wide association study of breakfast skipping links clock regulation with food timing

BACKGROUND

Little is known about the contribution of genetic variation to food timing, and breakfast has been determined to exhibit the most heritable meal timing. As breakfast timing and skipping are not routinely measured in large cohort studies, alternative approaches include analyses of correlated traits.

OBJECTIVES

The aim of this study was to elucidate breakfast skipping genetic variants through a proxy-phenotype genome-wide association study (GWAS) for breakfast cereal skipping, a commonly assessed correlated trait.

METHODS

We leveraged the statistical power of the UK Biobank (n = 193,860) to identify genetic variants related to breakfast cereal skipping as a proxy-phenotype for breakfast skipping and applied several in silico approaches to investigate mechanistic functions and links to traits/diseases. Next, we attempted validation of our approach in smaller breakfast skipping GWAS from the TwinUK (n = 2,006) and the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium (n = 11,963).

RESULTS

In the UK Biobank, we identified 6 independent GWAS variants, including those implicated for caffeine (ARID3B/CYP1A1), carbohydrate metabolism (FGF21), schizophrenia (ZNF804A), and encoding enzymes important for N6-methyladenosine RNA transmethylation (METTL4, YWHAB, and YTHDF3), which regulates the pace of the circadian clock. Expression of identified genes was enriched in the cerebellum. Genome-wide correlation analyses indicated positive correlations with anthropometric traits. Through Mendelian randomization (MR), we observed causal links between genetically determined breakfast skipping and higher body mass index, more depressive symptoms, and smoking. In bidirectional MR, we demonstrated a causal link between being an evening person and skipping breakfast, but not vice versa. We observed association of our signals in an independent breakfast skipping GWAS in another British cohort (P = 0.032), TwinUK, but not in a meta-analysis of non-British cohorts from the CHARGE consortium (P = 0.095).

CONCLUSIONS

Our proxy-phenotype GWAS identified 6 genetic variants for breakfast skipping, linking clock regulation with food timing and suggesting a possible beneficial role of regular breakfast intake as part of a healthy lifestyle.

Opportunistic feeding strategy in wild immature chimpanzees: Implications for children as active foragers in human evolution

Modern human (Homo sapiens) children are generally considered to be dependent on older individuals for foods, even after weaning. However, recent studies of hunter-gatherer societies have reported that children can also acquire food by themselves, although the degree of self-provisioning by children differs among groups and is considered a facultative adaptation. To investigate the dependence of children on older individuals for food and the importance of self-provisioning in early hominins, I examined feeding behavior in wild, immature chimpanzees (Pan troglodytes schweinfurthii). I studied 19 mother-offspring chimpanzee pairs in the Mahale Mountains National Park, Tanzania for approximately 22 months. Feeding behavior and interactions between mothers and their offspring were recorded. The results supported these three predictions: (1) immature chimpanzees need to feed more frequently than mothers because of increased basal metabolic rate and immature stomach capacity; (2) mothers provide effective opportunities to feed on high-quality food items which are similar to those of the mothers'; and (3) when feeding independently of their mothers, immature chimpanzees consume highly accessible food including non-adult foods nearby mothers to avoid getting lost and physical burden as with self-provisioning of human children in hunter gatherer societies. During non-simultaneous feeding bouts, immature individuals frequently consumed pith and wood. They may be valuable food items for immature individuals during their growth stage because they can be consumed year round and contain relatively higher crude ash and protein amounts, which may enable immature chimpanzees to manage the confines of their immature bodies, preventing them from matching adult feeding rhythms. This opportunistic feeding strategy is similar to self-provisioning by human children in hunter-gatherer societies. These results suggested that early hominin children performed self-provisioning based on opportunistic feeding strategies, and contributed to their food consumption by snacking in accordance with their metabolic needs and physical confines.

Time-restricted feeding reduces high-fat diet associated placental inflammation and limits adverse effects on fetal organ development

Maternal nutrition has become a major public health concern over recent years and is a known predictor of adverse long-term metabolic derangement in offspring. Time-restricted feeding (TRF), wherein food consumption is restricted to the metabolically active phase of the day, is a dietary approach that improves metabolic parameters when consuming a high-fat diet (HFD). Here, we tested whether TRF could reduce maternal HFD associated inflammation and thereby mitigate defects in fetal organ developmental. Female rats were kept on following three dietary regimens; Ad libitum normal chow diet (NCD-AL), Ad libitum HFD (HFD-AL) and Time-restricted fed HFD (HFD-TRF) from 5 months prior to mating and continued throughout pregnancy. Rat dams were sacrificed at embryonic day 18.5 (ED18.5) and placental tissues from these rats were processed for the analysis of cellular apoptosis, inflammatory cytokines (TNFα and IL-6), oxidative stress, endoplasmic reticulum (ER) stress and autophagy. Furthermore, fetal hepatic triglyceride (TG) content and fetal lung maturation were assessed at ED18.5. Biochemical analysis revealed that HFD-TRF rat had significantly lower serum TG levels and body weight compared to HFD-AL rats. Additionally, TRF significantly blocked HFD-induced placental apoptosis and inflammation via minimizing cellular stress, and restoring autophagic flux. In addition, fetal hepatosteatosis and delayed fetal lung maturation induced by HFD was significantly ameliorated in HFD-TRF compared to HFD-AL. Collectively, our results suggest that reducing placental inflammation via TRF could prevent adverse fetal metabolic outcomes in pregnancies complicated by maternal obesity.

Circadian Biology: Uncoupling Human Body Clocks by Food Timing

Synchrony of circadian rhythms between tissues/organs appears critical for health. A new study reports that meal timing, a modifiable temporal cue for the circadian system, can selectively uncouple circadian rhythms in metabolic physiology from the central circadian clock in humans.

Hormetic Effects of Phytochemicals on Health and Longevity

Caloric restriction, intermittent fasting, and exercise activate defensive cellular responses such as autophagy, DNA repair, and the induction of antioxidant enzymes. These processes improve health and longevity by protecting cells and organs against damage, mutations, and reactive oxygen species. Consuming a diet rich in vegetables, fruits, and mushrooms can also improve health and longevity. Phytochemicals such as alkaloids, polyphenols, and terpenoids found in plants and fungi activate the same cellular processes as caloric restriction, fasting, and exercise. Many of the beneficial effects of fruits and vegetables may thus be due to activation of stress resistance pathways by phytochemicals. A better understanding of the mechanisms of action of phytochemicals may provide important insights to delay aging and prevent chronic diseases.

Reasons for Late-Night Eating and Willingness to Change:A Qualitative Study in Pregnant Black Women

OBJECTIVE

Late-night eating during pregnancy is associated with greater risk for gestational diabetes. The purposes of this study were to describe reasons why women engage in late-night eating and to understand perceptions about changing this behavior.

DESIGN

Focus groups using a semi-structured interview script.

SETTING

Urban university-affiliated obstetric clinic.

PARTICIPANTS

Low-income black women (n = 18) with overweight/obesity at entry to prenatal care.

PHENOMENON OF INTEREST

Late-night eating.

ANALYSIS

Exhaustive approach coding responses to specific questions.

RESULTS

Individual and interpersonal contributors to late-night eating included hunger, altered sleep patterns, fetal movement, and the influence of others. Food choices were largely driven by taste and convenience. Some women reported that they could alter nightly eating patterns, whereas others would consider changing only if late-night eating were associated with a severe illness or disability for the child.

CONCLUSIONS AND IMPLICATIONS

There was considerable heterogeneity among the participants of this study regarding reasons for late-night eating during pregnancy and attitudes toward changing this behavior. Although the themes identified from this study cannot be generalized, they may be useful to inform future studies. Future research might develop strategies to overcome individual and social factors that contribute to late-night eating during pregnancy.

The role of intermittent fasting and meal timing in weight management and metabolic health

Obesity remains a major public health concern and intermittent fasting is a popular strategy for weight loss, which may present independent health benefits. However, the number of diet books advising how fasting can be incorporated into our daily lives is several orders of magnitude greater than the number of trials examining whether fasting should be encouraged at all. This review will consider the state of current understanding regarding various forms of intermittent fasting (e.g. 5:2, time-restricted feeding and alternate-day fasting). The efficacy of these temporally defined approaches appears broadly equivalent to that of standard daily energy restriction, although many of these models of intermittent fasting do not involve fed-fasted cycles every other 24 h sleep-wake cycle and/or permit some limited energy intake outside of prescribed feeding times. Accordingly, the intervention period therefore may not regularly alternate, may not span all or even most of any given day, and may not even involve absolute fasting. This is important because potentially advantageous physiological mechanisms may only be initiated if a post-absorptive state is sustained by uninterrupted fasting for a more prolonged duration than applied in many trials. Indeed, promising effects on fat mass and insulin sensitivity have been reported when fasting duration is routinely extended beyond sixteen consecutive hours. Further progress will require such models to be tested with appropriate controls to isolate whether any possible health effects of intermittent fasting are primarily attributable to regularly protracted post-absorptive periods, or simply to the net negative energy balance indirectly elicited by any form of dietary restriction.