Chrononutrition in type 2 diabetes mellitus and obesity: A narrative review.

Chrononutrition is a nutritional regimen that follows our biological clock, marked by the changes in metabolism that occur during the day. This regimen includes the distribution of energy, the regularity and frequency of meals, and the importance of these factors for metabolic health. A growing body of animal and human evidence indicates that the timing of food intake throughout the day can have a significant and beneficial impact on the metabolic health and well-being of individuals. In particular, both the timing and frequency of meals have been associated with obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, and other chronic conditions. Today's busy lifestyle makes many people skip breakfast and eat late at night. Eating late at night has been shown to cause a circadian misalignment, with the latter having a negative impact on weight control and glucose metabolism. Additionally, some studies have found a relatively strong association between skipping breakfast and insulin resistance, and T2DM. Against the backdrop of escalating obesity and T2DM rates, coupled with the recognized influence of food timing on disease evolution and control, this review aimed to synthesize insights from epidemiological and intervention studies of the interplay of timing of food intake and macronutrient consumption, reporting their impact on obesity and T2DM.

Association of the timing of evening eating with BMI Z-score and waist-to-height ratio among preschool-aged children in Finland.

Later timing of eating has been associated with higher adiposity among adults and children in several studies, but not all. Moreover, studies in younger children are scarce. Hence, this study investigated the associations of the timing of evening eating with BMI Z-score and waist-to-height ratio (WHtR), and whether these associations were moderated by chronotype among 627 preschoolers (3-6-year-olds) from the cross-sectional DAGIS survey in Finland. Food intake was measured with 3-d food records, and sleep was measured with hip-worn actigraphy. Three variables were formed to describe the timing of evening eating: (1) clock time of the last eating occasion (EO); (2) time between the last EO and sleep onset; and (3) percentage of total daily energy intake (%TDEI) consumed 2 h before sleep onset or later. Chronotype was assessed as a sleep debt-corrected midpoint of sleep on the weekend (actigraphy data). The data were analysed with adjusted linear mixed effects models. After adjusting for several confounders, the last EO occurring closer to sleep onset (estimate = -0·006, 95 % CI (-0·010, -0·001)) and higher %TDEI consumed before sleep onset (estimate = 0·0004, 95 % CI (0·00003, 0·0007)) were associated with higher WHtR. No associations with BMI Z-score were found after adjustments. Clock time of the last EO was not significantly associated with the outcomes, and no interactions with chronotype emerged. The results highlight the importance of studying the timing of eating relative to sleep timing instead of only as clock time.

Is time of eating associated with BMI and obesity? A population-based study.

PURPOSE: Time-related eating patterns have been associated with metabolic and nutritional diseases such as obesity. However, there is a lack of representative studies on this subject. This study's aim was to assess the association between the timing of eating and obesity in a large and representative sample of the Brazilian adult population (POF 2008-2009 survey). METHODS: Two days of adults' food diary (n = 21,020) were used to estimate tertiles of first and last meal intake times, eating midpoint, caloric midpoint time, and calories consumed from 18:00 h onwards. BMI was estimated and its values, as well as excess weight (BMI ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were used as outcomes. Multiple linear and logistic regressions were performed. RESULTS: The first (ß = 0.65, 95% CI 0.37-0.93) and last food intake time (ß = 0.40, 95% CI 0.14-0.66), eating midpoint (ß = 0.61, 95% CI 0.34-0.88) and calories consumed after 21:00 h (ß = 0.74, 95% CI 0.32-1.16) and 22:00 h (ß = 0.75, 95% CI 0.18-1.32) were positively associated with BMI. The likelihood of having excess weight or obesity was significantly higher in the third tertile of the first food intake time (OR = 1.28, 95% CI 1.13-1.45 and OR = 1.34, 95% CI 1.13-1.58, respectively), last food intake time (OR = 1.16, 95% CI 1.03-1.32; and OR = 1.18, 95% CI 1.00-1.41, respectively), eating midpoint (OR = 1.28, 95% CI 1.13-1.45; and OR = 1.35, 95% CI 1.14-1.59, respectively) and energy consumption after 21:00 h (OR = 1.33, 95% CI 1.10-1.59). CONCLUSION: Chrononutrition meal patterns indicative of late meal intake were significantly associated with high BMI, excess weight and obesity in the Brazilian population.

The association between diet quality and chrononutritional patterns in young adults.

PURPOSE: Young adults eat erratically and later in the day which may impact weight and cardiometabolic health. This cross-sectional study examined relationships between chrononutritional patterns and diet quality in two young adult populations: a university and community sample. METHODS: Three days of dietary data were collected including food images captured using wearable cameras. Chrononutritional variables were extracted: time of first and last eating occasions, caloric midpoint (time at which 50% of daily energy was consumed), number of eating occasions per day, eating window, day-to-day variability of the above metrics, and evening eating (≥20:00h). The Healthy Eating Index for Australian Adults scored diet quality. Statistical analyses controlled for gender, body mass index, and socio-economic status. RESULTS: No significant associations between chrononutritional patterns and diet quality were found for all participants (n = 95). However, differences in diet quality were found between university (n = 54) and community (n = 41) samples with average diet quality scores of 59.1 (SD 9.7) and 47.3 (SD 14.4), respectively. Of those who extended eating ≥20:00 h, university participants had better diet quality (62.9±SE 2.5 vs. 44.3±SE 2.3, p < 0.001) and discretionary scores (7.9±SE 0.9 vs. 1.6±SE 0.6, p < 0.001) than community participants. University participants consumed predominately healthful dinners and fruit ≥20:00h whereas community participants consumed predominately discretionary foods. CONCLUSION: For the general young adult population, meal timing needs to be considered. Food choices made by this cohort may be poorer during evenings when the desire for energy-dense nutrient-poor foods is stronger. However, meal timing may be less relevant for young adults who already engage in healthy dietary patterns.

Habitual food consumption, eating behavior and meal-timing among Jordanian adults with elevated Blood pressure: a cross-sectional population-based study.

BACKGROUND: The prevalence of elevated blood pressure (BP) has been raised worldwide. Food consumption, eating habits, and nutritional lifestyle related to meal timing, skipping meals, and meal contents have recently received more attention in studies on BP and metabolic syndrome. Purpose: This study evaluated the association between habitual food consumption, eating behavior, and meal timing with BP among Jordanian adults. METHODS: A cross-sectional study included 771 Jordanian adults. A food frequency questionnaire was completed. Data about eating habits, meal timing, and emotional eating were collected. BP was measured. RESULTS: The prevalence of less than recommended intake of vegetables, milk, protein, and fruits was higher in participants with elevated BP (69.2%, 90.2%, 58.9%, and 25.5%, respectively) as compared to the normal BP group (p < 0.001). Consuming vegetables and milk less than the recommended was reported to significantly increase the likelihood of elevated BP by OR= (1.60, and 2.75 (95%CI: 1.06-2.40; 1.62-4.66). Hence, consuming more than recommended fruit reduced the risk of elevated BP by OR = 0.56 (95%CI: 0.38-0.82). A 63.2% of elevated BP participants have three meals daily, a higher percentage of intake of one (23.5%) and two (45.7%) snacks. However, they had a higher percentage of morning eaters (50.7%), had lunch between 1:00-6:00 PM (92.7%), and had dinner between 6:00 and 9:00 PM (68.1%). CONCLUSIONS: Although Jordanian adults with elevated BP appear to have healthy eating habits and meal timing and frequency, their habitual food consumption falls short of the daily recommendations for milk, fruits, vegetables, and protein.

Numerous epidemiological studies have revealed a steadily rising prevalence of elevated BP, and one critical independent and modifiable risk factor for this condition is obesity.One global non-communicable diseases (NCD) target adopted by the World Health Assembly in 2013 is to lower the prevalence of raised BP by 25% by 2025 compared with its 2010 level.Lifestyle improvement is a cornerstone of CVD prevention; diet is one of the most effective strategies for attaining BP reduction and control as low-salt diets, dietary approaches to stop hypertension (DASH), a low-salt Mediterranean diet, an energy-restriction diet, vegetarian diet, and alternate-day fasting.Eating habits and nutritional lifestyle related to meal timing, skipping meals, and meal contents have recently received more attention in studies on BP and metabolic syndrome.a relationship between elevated BP and metabolic syndrome, infrequent fruit eating, skipping meals, irregular meal frequency and timing, and obesity has been found among adults.It has been found that earlier meal timing could reduce cardiometabolic disease burden and aid in weight loss; on the other hand, meal frequency was inversely associated with the prevalence of abdominal obesity, elevated BP, and elevated triglycerides. Morning eating was associated with a lower prevalence of metabolic syndrome than no morning eating.

Sociocultural influences on dietary behavior and meal timing among Native Hawaiian and Pacific Islander women at risk of endometrial cancer: a qualitative investigation.

PURPOSE: Determine sociocultural influences on dietary behavior, body image, weight loss, and perceptions of the cultural appropriateness of a meal-timing intervention design and menu among Native Hawaiian and Pacific Islander (NHPI) women at risk of endometrial cancer. METHODS: Six 90-min videoconference focus groups among NHPI women (n = 35) recruited by a community champion in Utah. Eligible women were aged ≥ 18 years at risk of endometrial cancer (i.e., BMI ≥ 25 kg/m2, history of non-insulin-dependent diabetes or complex atypical endometrial hyperplasia) had a working cell phone capable of downloading a phone app, could use their cell phone during the day, and were not night-shift workers. Twelve semi-structured questions were posed during the focus groups. Using inductive qualitative methods based on Hatch's 9-step approach, de-identified transcript data were analyzed. RESULTS: Overarching themes included economic factors, cultural influences, meal choice and timing, and perceptions of health. Subthemes included affordability, waste avoidance, inundated schedules, and cultural influences. Perceptions of body size and weight loss were influenced by family, community, and social media, whose messages could be conflicting. Important intervention components included satisfying, convenient pre-made meals, while barriers included the need to cook for family members. CONCLUSIONS: Dietary interventions targeting metabolic health among NHPI women should consider the multitude of sociocultural and economic factors that influence food choices and meal timing in this population, including affordability, hectic schedules, and immigrant adjustment. Promoting the link between physical and mental well-being as opposed to weight loss is a key approach to reaching this population.

Frequency of Consuming Breakfast Meals and After-Dinner Snacks Is not Associated with Postmenopausal Breast Cancer Risk: Women's Health Initiative Observational Study.

BACKGROUND: There has been little investigation into how the timing of meals and eating occasions associates with postmenopausal breast cancer risk. OBJECTIVE: We examined the association between the frequency of consuming breakfast meals and after-dinner snacks with the risk for postmenopausal breast cancer. METHODS: A prospective analysis of 74,825 postmenopausal women aged 49 to 81 y from the Women's Health Initiative Observational Study cohort. Breakfast and after-dinner snack intake were assessed at year 1 examination. Risk for invasive and in situ breast cancer diagnosed before 28 February 2020 was modeled with multivariable Cox proportional hazards regression models according to breakfast and after-dinner snack consumption frequencies. The models were adjusted for age, self-identified race/ethnicity, education, income, physical activity, smoking, alcohol intake, diet quality score (Healthy Eating Index 2015), energy intake, diabetic status, hormone therapy, and BMI. RESULTS: During the follow-up period, 5313 participants were diagnosed with invasive breast cancer and 1197 participants with in situ breast cancer. Compared with participants who did not eat breakfast, those with daily breakfast consumption was not associated with invasive breast cancer (HR: 1.04; 95% CI: 0.9, 1.19) nor in situ (HR: 1.25; 95% CI: 0.91, 1.74) breast cancer. There were monotonic higher point estimates of in situ breast cancer for each higher category of breakfast intake from 0 to 7 times per week (P-trend = 0.04, Wald test). Compared with consumption of daily after-dinner snacks, avoidance of after-dinner snacks was not associated with invasive breast cancer (HR: 0.97; 95% CI: 0.87, 1.08) nor in situ (HR: 1.12; 95% CI: 0.89, 1.42) breast cancer. CONCLUSIONS: There was no association between intake frequency of breakfast meals or after-dinner snack habits and with risk of breast cancer in postmenopausal women.

Self-Reported Eating-Occasion Frequency and Timing are Reproducible and Relatively Valid in the American Cancer Society Cancer Prevention Study-3 Diet Assessment Substudy.

BACKGROUND: Accurate assessment of eating-occasion behaviors, such as timing, frequency, and consumption intervals, is important for evaluating associations with obesity and other chronic diseases. OBJECTIVES: The main objective of this study was to assess the relative validity of a 24-hour grid approach to assess eating-occasion timing and frequency in comparison to data derived from repeated 24-hour dietary recalls (DRs). A second objective was to assess the 1-year test-retest reproducibility of the 24-hour grid. METHODS: Between 2015 and 2016, 626 participants in the Cancer Prevention Study-3 (CPS-3) Diet Assessment Substudy (mean age, 52 years; age range, 31-70 years; 64% female; 64% non-Hispanic white, 22% non-Hispanic black, 14% Hispanic) completed 2 grids and up to 6 unannounced, telephone, interviewer-administered DRs over 1 year. Spearman correlations (ρ; 95% CIs) were calculated to assess reproducibility between the repeated eating-occasion grid-derived variables (e.g., numbers of snacks and meals per day, timing of eating occasions) and to assess relative validity by comparing the meal grid and DR-derived summary data separately for weekdays and weekend days. RESULTS: Reproducibility correlations for eating-occasion variables derived from the eating-occasion grids completed 1 year apart were ≥0.5 for the majority of variables analyzed for both weekdays and weekend days, including numbers of snacks and meals per day and timing of the first and last eating occasions of the day. Relative validity was highest among weekday variables and was ≥0.5 for the majority of variables, with correlations ranging from ρ values of 0.32 (number of meals per day) to 0.68 (hour of the first eating occasion). CONCLUSIONS: These findings suggest the eating-occasion grid used in CPS-3 has good reproducibility over 1 year and yields estimates comparable to those from a more detailed method of assessment of eating timing and frequency.

Desynchronization between Food Intake and Light Stimulations Induces Uterine Clock Quiescence in Female Mice.

BACKGROUND: Dysmenorrhea is associated with breakfast skipping in young women, suggesting that fasting in the early active phase disrupts uterine functions. OBJECTIVES: To investigate the possible involvement of the uterine clock system in fasting-induced uterine dysfunction, we examined core clock gene expressions in the uterus using a 28-h interval-fed mouse model. METHODS: Young female mice (8 wk of age) were divided into 3 groups: group I (ad libitum feeding), group II (time-restricted feeding, initial 4 h of the active period every day), and group III (time-restricted feeding for 8 h with a 28-h cycle). Groups II and III have the same fasting interval of 20 h. After analyzing feeding and wheel running behaviors during 2 wk of dietary restriction, mice were sacrificed at 4-h intervals, and the expression profiles of clock genes in the uterus and liver were examined by qPCR. RESULTS: The mice in group I took food mainly during the dark phase and those in group II during the initial 4 h of the dark phase, whereas those in group III delayed feeding time by 4 h per cycle. In all groups, spontaneous wheel running was observed during the dark phase. There was no difference in the quantity of feeding and the amount of running exercise among the 3 groups during the second week. The mRNA expressions of peripheral clock genes, Bmal1, Clock, Per1, Per2, Cry1, Nr1d1, and Dbp and a clock-controlled gene, Fabp1, in the uterus showed rhythmic oscillations with normal sequential expression cascade in groups I and II, whereas their expressions decreased and circadian cycles disappeared in group III. In contrast, liver core clock genes in group III showed clear circadian cycles. CONCLUSIONS: Fluctuations in the timing of the first food intake impair the uterine clock oscillator system to reduce clock gene expressions and abolish their circadian rhythms.

Delayed Eating Schedule Raises Mean Glucose Levels in Young Adult Males: a Randomized Controlled Cross-Over Trial.

BACKGROUND: Misalignment of meals to the biological clock may cause adverse effects on glucose metabolism. However, the effects of repeated different eating schedules (early compared with late) on glucose concentration throughout the day are poorly understood. OBJECTIVES: We examined the effects of different eating schedules on the 24-h glucose response using a continuous glucose monitor (CGM). METHODS: Eight young adult males (age, 20.9 ± 3.4 y; body mass index: 21.3 ± 1.8 kg/m2) each followed 2 different eating schedules (early [08:30, 13:30, and 19:30] and late [12:00, 17:00, and 23:00]) in random order. These diet interventions were conducted for 8 d, with an experimental period of 3 d and 2 nights (from dinner on day 7) after 7 d of free living. The 3 meals in each intervention were nutritionally equivalent (55% carbohydrate, 15% protein, and 30% fat). The 24-h mean interstitial glucose concentration on day 8 was obtained under controlled conditions using the CGM (primary outcome). These concentrations were compared among the following 3 schedules using Dunnett's test, with the early eating schedule as reference (1 compared with 2 and 1 compared with 3): 1) early eating schedule (control), 2) late eating schedule according to the clock time (08:00 on day 8 to 08:00 on day 9), and 3) late eating schedule according to the time elapsed since the first meal for 24 h. RESULTS: The 24-h mean ± SD interstitial glucose concentrations when participants followed the late eating schedule were higher than those when they followed the early eating schedule in terms of clock time (91.2 ± 2.9 compared with 99.2 ± 4.6 mg/dL, P = 0.003) and time elapsed (91.2 ± 2.9 compared with 98.3 ± 3.8 mg/dL, P < 0.001). CONCLUSIONS: A late eating schedule increases the mean 24-h interstitial glucose concentration in young adult males. This insight will have useful implications in determining meal timings, especially for those with conditions such as diabetes.

The impact of experimentally shortened sleep on timing of eating occasions in adolescents: A brief report.

Short sleep increases the risk for obesity in adolescents. One potential mechanism relates to when eating occurs in the day. This study investigated the impact of shortened sleep on eating occasion timing in adolescents. Ninety-three healthy 14- to 17-year-olds (62% female) completed a within-subject experimental sleep manipulation, engaging in 5-night spans of Short Sleep (6.5-hr sleep opportunity) or Healthy Sleep (9.5-hr sleep opportunity), with order randomized. During each condition, adolescents completed three 24-hr diet recall interviews. Repeated-measure t-tests assessed the sleep manipulation effect on each adolescent's number of meals, first and last eating occasion (relative to the clock and time since sleep onset/offset), feeding window (timespan from first to last eating), and the midpoint of feeding. The timing of the first eating occasion was similar across conditions, relative to the clock (Short = 08:51, Healthy = 08:52) and to time since waking (Short = 2.0 hr, Healthy = 2.2 hr). The timing of the last eating occasion was later relative to the clock (Short = 20:34, Healthy = 19:39; p < 0.001), resulting in a longer feeding window (Short = 11.7 hr, Healthy = 10.8 hr, p < 0.001) and a later midpoint in the feeding window (Short = 14:41, Healthy = 14:18, p = 0.002). The gap between last eating occasion and sleep onset was larger in Short (4.2 hr) than Healthy Sleep (2.9 hr; p < 0.001), though the last eating occasion was much earlier than when they fell asleep during either condition. Shortened sleep resulted in adolescents eating later and lengthening the daily feeding window. These findings may help explain the link between shortened sleep and increased obesity risk in adolescents.

Meal timing of dietary total antioxidant capacity and its association with all-cause, CVD and cancer mortality: the US national health and nutrition examination survey, 1999-2018.

BACKGROUND: The association of the meal timing of dietary total antioxidant capacity (DAC) with mortality is unclear. We aimed to investigate the association between the meal timing of DAC and all-cause, cardiovascular disease (CVD), and cancer mortality in general adult populations. METHODS: A total of 56,066 adults who participated in the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 were recruited for this study. Dietary intake (quantity and timing) was evaluated by nonconsecutive 24-h dietary recalls. The main exposure variables were the DAC across three meals (total, breakfast, lunch, and dinner; without coffee) and the difference between dinner and breakfast DAC (Δ = dinner-breakfast; without coffee). The outcomes were all-cause, CVD, and cancer mortality. The adjusted hazard ratios [aHRs] and 95% confidence intervals [CI] were imputed by Cox proportional hazards regression. RESULTS: Among the 56,066 participants, there were 8566 deaths from any cause, including 2196 from CVD and 1984 from cancer causes. Compared to participants in the lowest quintiles of the total DAC, those in the highest quintiles had 34% and 27% decreased risks of all-cause and CVD mortality, respectively (all-cause mortality: aHRs 0.66 [95% CI 0.57-0.76]; CVD mortality: aHRs 0.73 [95% CI 0.57-0.94]). More importantly, participants in the highest quintiles of the dinner DAC, but not those in that of breakfast or lunch, had a 24% decrease in all-cause mortality (aHRs 0.76 [95% CI 0.67-0.87]) compared with those in the lowest quintiles. Inverse associations were further confirmed for Δ DAC (aHRs 0.84 [95% CI 0.74-0.96]). Above associations did not change when including DAC from snacks or tea. Mediation analysis showed that the total associations of total, dinner or Δ DACs with reduced all-cause mortality were 24%, 13% and 6%, respectively, mediated by serum CRP. Additionally, all-cause mortality was decreased by 7% in models replacing 10% breakfast DAC (aHRs 0.93 [95% CI 0.9-0.97]) with an equivalent proportion of dinner DAC. For cancer mortality, no statistical significance was detected in the adjusted models. CONCLUSIONS: The findings emphasize the putative beneficial relationship of a diet rich in antioxidants and meal timing on serum CRP and all-cause mortality.

Association of meal timing of energy, macronutrients and foods with hypercholesterolaemia in the US adults.

Few studies examined the association of energy, macronutrients and food consumption at dinner v. breakfast with hypercholesterolaemia. A total of 27 911 participants from the National Health and Nutrition Examination Survey (2003-2016) were included in the cross-sectional study. Energy, macronutrients and food consumption at breakfast, dinner and the difference at dinner v. breakfast (Δratio) were calculated. Multiple logistic regression models and substitution effects of foods at dinner with breakfast were also performed. After adjustment for potential covariates, compared with the lowest quintile, participants in the highest quintile of Δratio in terms of energy had a higher risk of prevalent hypercholesterolaemia (ORΔratio of energy 1·16, 95 % CI (1·01, 1·33)) mainly due to Δratio of low-quality carbohydrates and plant protein (ORΔratio of low-quality carbohydrates 1·19; 95 % CI (1·05, 1·35)); ORΔratio of plant protein 1·13; 95 % CI (1·01, 1·28)). ΔAdded sugars and Δnuts were associated with hypercholesterolaemia (ORΔadded sugars 1·01; 95 % CI (1·00, 1·02)); ORΔnuts 1·08; 95 % CI (1·01, 1·16)). Furthermore, the substitution of added sugars, nuts and processed meat at dinner with breakfast could reduce the OR of hypercholesterolaemia. This study indicated that among US adults, overconsumption of energy, macronutrients including low-quality carbohydrates and plant protein at dinner than breakfast was significantly associated with a higher risk of prevalent hypercholesterolaemia. The replacing of added sugar, nuts and processed meat at dinner with breakfast reduced the risk of prevalent hypercholesterolaemia. This study emphasised the importance of meal timing in the prevention of hypercholesterolaemia.

Meal-timing patterns and chronic disease prevalence in two representative Austrian studies.

PURPOSE: This study aimed at describing meal-timing patterns using cluster analysis and explore their association with sleep and chronic diseases, before and during COVID-19 mitigation measures in Austria. METHODS: Information was collected in two surveys in 2017 (N = 1004) and 2020 (N = 1010) in representative samples of the Austrian population. Timing of main meals, nighttime fasting interval, last-meal-to-bed time, breakfast skipping and eating midpoint were calculated using self-reported information. Cluster analysis was applied to identify meal-timing clusters. Multivariable-adjusted logistic regression models were used to study the association of meal-timing clusters with prevalence of chronic insomnia, depression, diabetes, hypertension, obesity and self-rated bad health status. RESULTS: In both surveys, median breakfast, lunch and dinner times on weekdays were 7:30, 12:30 and 18:30. One out of four participants skipped breakfast and the median number of eating occasions was 3 in both samples. We observed correlation between the different meal-timing variables. Cluster analysis resulted in the definition of two clusters in each sample (A17 and B17 in 2017, and A20 and B20 in 2020). Clusters A comprised most respondents, with fasting duration of 12-13 h and median eating midpoint between 13:00 and 13:30. Clusters B comprised participants reporting longer fasting intervals and later mealtimes, and a high proportion of breakfast skippers. Chronic insomnia, depression, obesity and self-rated bad health-status were more prevalent in clusters B. CONCLUSIONS: Austrians reported long fasting intervals and low eating frequency. Meal-timing habits were similar before and during the COVID-19-pandemic. Besides individual characteristics of meal-timing, behavioural patterns need to be evaluated in chrono-nutrition epidemiological studies.

Maternal melatonin levels and temporal dietary intake: results from MY-CARE cohort study.

Chrononutrition emerges as a novel approach to promote circadian alignment and metabolic health by means of time-of-the-day dietary intake. However, the relationship between maternal circadian rhythm and temporal dietary intake during pregnancy remains understudied. This study aimed to determine the change in melatonin levels in pregnant women across gestation and its association with temporal energy and macronutrient intake. This was a prospective cohort involving 70 healthy primigravidas. During the second and third trimesters, pregnant women provided salivary samples collected at 9:00, 15:00, 21:00, and 3:00 h over a 24 h day for melatonin assay. Data on chrononutrition characteristics were collected using a 3-day food record. Parameters derived from melatonin measurements including mean, amplitude, maximal level, area under the curve with respect to increase (AUCI), and area under the curve with respect to ground (AUCG) were computed. A rhythmic melatonin secretion over the day that remained stable across trimesters was observed among the pregnant women. There was no significant elevation in salivary melatonin levels as pregnancy advanced. In the second trimester, higher energy intake during 12:00-15:59 h and 19:00-06:59 h predicted a steeper melatonin AUCI (ß=-0.32, p = 0.034) and higher AUCG (ß = 0.26, p = 0.042), respectively. Macronutrient intake within 12:00-15:59 h was negatively associated with mean melatonin (Fat: ß=-0.28, p = 0.041) and AUCG (Carbohydrate: ß=-0.37, p = 0.003; Protein: ß=-0.27, p = 0.036; Fat: ß=-0.32, p = 0.014). As pregnant women progressed from the second to the third trimester, a flatter AUCI was associated with a reduced carbohydrate intake during 12:00-15:59 h (ß=-0.40, p = 0.026). No significant association was detected during the third trimester. Our findings show that higher energy and macronutrient intakes particularly during 12:00-15:59 h and 19:00-06:59 h are associated with the disparities in maternal melatonin levels. Findings suggest the potential of time-based dietary approaches to entrain circadian rhythm in pregnant women.

Characterizing naturalistic meal timing, energy intake, and macronutrient intake among individuals with loss of control eating.

Binge eating demonstrates an evening diurnal shift among individuals with eating disorders. Disruptions to diurnal appetitive rhythms may be somewhat chronic and set the stage for additional disruptions to prompt binge eating. Despite known diurnal shifts in binge eating and related constructs (e.g., mood) and detailed characterizations of binge-eating episodes, no findings to date describe the naturalistic diurnal timing and composition of energy and nutrient intake on days with and without loss of control eating. We aimed to characterize eating behaviors (i.e., meal timing, energy intake, and macronutrient composition) across seven days in individuals with binge-spectrum eating disorders, assessing differences between eating episodes and days with and without loss of control eating. Undergraduate students (N = 51; 76.5% female) who endorsed past 28-day loss of control eating completed a 7-day naturalistic ecological momentary assessment protocol. Participants completed daily food diaries and reported instances of loss of control eating across the 7-day period. Results indicated that episodes of loss of control were more likely to occur later in the day, but overall meal timing did not differ across days with and without loss of control. Similarly, greater caloric consumption was more likely for episodes with loss of control, but overall caloric consumption did not differ between days with and without loss of control. Analysis of nutritional content demonstrated differences between both episodes and days with and without loss of control for carbohydrates and total fats, but not for protein. Findings provide support for the hypothesized role disruptions in diurnal appetitive rhythms play in maintaining binge eating via consistent irregularities, underscoring the importance of examining treatment adjuncts that intervene on the regulation of meal timing to enhance eating disorder treatment outcomes.

Associations of the timing of sleep and meals with the presence of gastroesophageal reflux disease in community-dwelling women in Japan.

BACKGROUND: It has been suspected that circadian rhythms may play a part in the pathogenesis of gastrointestinal diseases including gastroesophageal reflux disease (GERD). The present study aimed to examine the cross-sectional association of the timing of sleep and meals with the presence of GERD in community-dwelling women in Japan. METHODS: In total, 605 women responded to a self-administered questionnaire asking for information on GERD symptoms, sleep habits, sleep disturbances and the timing of meals. GERD symptoms were evaluated using the Frequency Scale for the Symptoms of GERD, and participants with a score of more than seven points were classified as having GERD. RESULTS: In total, 104 (17.2%) women were found to have GERD. Later bedtime on both weekdays and weekends and later midpoint of sleep were significantly associated with the odds ratios (OR) of GERD after controlling for covariates: ORs for each 1 h delay were 1.31 (95% confidence interval [CI] = 1.03-1.68), 1.38 (95% CI = 1.08-1.75) and 1.43 (95% CI = 1.06-1.95). Having lunch at irregular times was significantly associated with the increased OR of GERD (1.99; 95% CI = 1.02-3.91). Longer overnight fasting duration and longer time intervals from the midpoint of sleep to breakfast and lunch were significantly associated with decreased OR of GERD (ORs for each 1 h increase were 0.73 [95% CI = 0.56-0.95], 0.64 [95% CI = 0.46-0.88] and 0.70 [95% CI = 0.51-0.96]). CONCLUSIONS: These data suggest that the timing of sleep and timing of meals relative to the sleep/wake cycle are associated with the presence of GERD.

Circadian Disruption and Mental Health: The Chronotherapeutic Potential of Microbiome-Based and Dietary Strategies.

Mental illness is alarmingly on the rise, and circadian disruptions linked to a modern lifestyle may largely explain this trend. Impaired circadian rhythms are associated with mental disorders. The evening chronotype, which is linked to circadian misalignment, is a risk factor for severe psychiatric symptoms and psychiatric metabolic comorbidities. Resynchronization of circadian rhythms commonly improves psychiatric symptoms. Furthermore, evidence indicates that preventing circadian misalignment may help reduce the risk of psychiatric disorders and the impact of neuro-immuno-metabolic disturbances in psychiatry. The gut microbiota exhibits diurnal rhythmicity, as largely governed by meal timing, which regulates the host's circadian rhythms. Temporal circadian regulation of feeding has emerged as a promising chronotherapeutic strategy to prevent and/or help with the treatment of mental illnesses, largely through the modulation of gut microbiota. Here, we provide an overview of the link between circadian disruption and mental illness. We summarize the connection between gut microbiota and circadian rhythms, supporting the idea that gut microbiota modulation may aid in preventing circadian misalignment and in the resynchronization of disrupted circadian rhythms. We describe diurnal microbiome rhythmicity and its related factors, highlighting the role of meal timing. Lastly, we emphasize the necessity and rationale for further research to develop effective and safe microbiome and dietary strategies based on chrononutrition to combat mental illness.

Nutrient timing and metabolic regulation.

Daily (circadian) rhythms coordinate our physiology and behaviour with regular environmental changes. Molecular clocks in peripheral tissues (e.g. liver, skeletal muscle and adipose) give rise to rhythms in macronutrient metabolism, appetite regulation and the components of energy balance such that our bodies can align the periodic delivery of nutrients with ongoing metabolic requirements. The timing of meals both in absolute terms (i.e. relative to clock time) and in relative terms (i.e. relative to other daily events) is therefore relevant to metabolism and health. Experimental manipulation of feeding-fasting cycles can advance understanding of the effect of absolute and relative timing of meals on metabolism and health. Such studies have extended the overnight fast by regular breakfast omission and revealed that morning fasting can alter the metabolic response to subsequent meals later in the day, whilst also eliciting compensatory behavioural responses (i.e. reduced physical activity). Similarly, restricting energy intake via alternate-day fasting also has the potential to elicit a compensatory reduction in physical activity, and so can undermine weight-loss efforts (i.e. to preserve body fat stores). Interrupting the usual overnight fast (and therefore also the usual sleep cycle) by nocturnal feeding has also been examined and further research is needed to understand the importance of this period for either nutritional intervention or nutritional withdrawal. In summary, it is important for dietary guidelines for human health to consider nutrient timing (i.e. when we eat) alongside the conventional focus on nutrient quantity and nutrient quality (i.e. how much we eat and what we eat).

The Impact of Meal Timing on Risk of Weight Gain and Development of Obesity: a Review of the Current Evidence and Opportunities for Dietary Intervention.

PURPOSE OF REVIEW: The aim of this short review is to provide an updated commentary on the current literature examining the impact of meal timing on obesity and weight gain in adults. The potential mechanisms, including novel and emerging factors, behind timing of food intake across the 24-h period in the development of obesity, and dietary strategies manipulating meal timing to ameliorate weight gain are also explored. RECENT FINDINGS: Dietary patterns that feature meal timing outside of the regular daytime hours can contribute to circadian disruption as food is metabolised in opposition to internal daily rhythms and can feedback on the timekeeping mechanisms setting these rhythms. Epidemiological evidence examining the impact of late meal timing patterns is beginning to suggest that eating at night increases the risk of weight gain over time. Mechanisms contributing to this include changes to the efficiency of metabolism across the day, and dysregulation of appetite hormone and gut microbiota by mis-timed meals. When meals are eaten, in relation to the time of day, is increasingly considered of importance when implementing dietary change in order to address the growing burden of obesity, although further research is required in order to determine optimal patterns.