Meal patterns, including intermittent fasting - a scoping review for Nordic Nutrition Recommendations 2023

Introduction

'Meal patterns' refers to eating frequency, snacking, regularity, and timing. Here also including intermittent fasting. The effect of meal patterns on health is inconsistent and when updating the Nordic Nutrition Recommendations 2023 (NNR2023), summarizing the evidence is important.

Aims

To describe the evidence for the role of meal patterns on bodyweight, body composition, and cardiovascular risk factors (i.e. blood pressure and lipid- and glukose metabolism) in healthy people living with normal weight, overweight, or obesity in all age groups.

Methods

An initial search in PubMed found 481 reviews, of which 104 were identified based on titles. Of these, 47 were excluded based on title and abstracts. Of the remaining 57 reviews, 16 were included reporting search terms and inclusion/exclusion criteria. In addition, 8 reviews from reference list or known by authors were included. In total, 24 reviews were relevant. Cochrane Library was searched with no results.

Results

All reviews were rated low or critically low (AMSTAR 2). No consistent findings on eating frequency and body weight or composition were found in children/adolescents or adults. In snacking, mixed results were found, although among adults, some consistent results showed positive associations between snacking and body weight. In regularity, breakfast skipping showed mixed results in children/adolescents on body weight and composition. Among adults, randomized controlled trials on breakfast skipping showed a minor impact on improved weight loss. In prospective studies on timing, lower energy intake during late afternoon/evening was related to less body weight. Intermittent fasting reduced body weight but was not superior to continuous energy restrictions. Cardiovascular risk factors were assessed in a minority of the reviews, and despite some beneficial effects, the evidence was limited.

Conclusion

Given the overall low to critically low quality of the reviews, the evidence is limited and inconclusive. No consistent results providing evidence for setting recommendations for meal patterns were shown. In this regard, meal patterns may vary within the context of an energy balanced and nutritionally adequate diet.

Changes in eating patterns in response to chronic insufficient sleep and their associations with diet quality: a randomized trial

STUDY OBJECTIVES

Insufficient sleep leads to overconsumption, but the factors contributing to this effect are poorly understood. Therefore, we assessed the influence of prolonged curtailment of sleep on free-living eating patterns linked with overconsumption and explored associations of these eating patterns with diet quality under different sleep conditions.

METHODS

Sixty-five adults (47 females) participated in outpatient randomized crossover studies with two 6-week conditions: adequate sleep (7-9 h/night) and sleep restriction (-1.5 h/night relative to screening). Food records were collected over 3 nonconsecutive days, from which we ascertained data on eating frequency, midpoint, and window and intakes of energy and nutrients. Linear mixed models were used to assess the impact of sleep condition on change in eating pattern (sleep × week interaction) and the relation between eating patterns and dietary intakes (sleep × eating pattern interaction).

RESULTS

Sleep condition impacted the change in eating frequency across weeks, with eating frequency increasing in sleep restriction relative to adequate sleep (β = 0.3 ± 0.1; P = .046). Across conditions, eating more frequently tended to relate to higher energy intakes (β = 60.5 ± 34.6; P = .082). Sleep also influenced the relation of variability in eating midpoint with intakes of saturated fat (β = 6.0 ± 2.1; P = .005), polyunsaturated fat (β = -3.9 ± 2.0; P = .051), and added sugar (β = 17.3 ± 6.2; P = .006), with greater midpoint variability associated with more adverse changes in these diet quality components in sleep restriction vs adequate sleep.

CONCLUSIONS

Chronic short sleep increases eating frequency and adversely influences associations of variability in meal timing with components of diet quality. These findings help to explain how short sleep leads to overconsumption and obesity.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Impact of Sleep Restriction in Women; URL: https://clinicaltrials.gov/ct2/show/NCT02835261; Identifier: NCT02835261 and Name: Impact of Sleep Restriction on Performance in Adults; URL: https://clinicaltrials.gov/ct2/show/NCT02960776; Identifier: NCT02960776.

CITATION

Barragán R, Zuraikat FM, Tam V, RoyChoudhury A, St-Onge M-P. Changes in eating patterns in response to chronic insufficient sleep and their associations with diet quality: a randomized trial. J Clin Sleep Med. 2023;19(11):1867-1875.

Eating Frequency in European Children from 1 to 96 Months of Age: Results of the Childhood Obesity Project Study

We aimed to investigate the eating frequency (EF) in children over age, and examined the influence of country, sex, feeding mode and weight status on EF. We used the dietary data of the Childhood Obesity Project, which comprised European children from five countries. Dietary data of 3-days weighed and estimated records were available monthly from 1 to 9 and at 12-, 24-, 36-, 48-, 60-, 72- and 96-months old. Generalized additive mixed effects models were used to estimate EF trajectories with EF as outcome and applying age splines. Additionally, the models were further adjusted for country, feeding mode, sex or weight status. Data from 1244 children were analysed. EF was highest at 1 month with on average 7.3 ± 1.9 feeds per day, and fell to 5.1 ± 1.1 eating occasions at the age 96 months. Night feeding was similarly often than day feeding at 1 month but declined thereafter. Significant differences in EF were observed between countries (p < 0.05), with the highest EF in Poland, and between infant feeding modes, with a higher EF in breastfed than non-breastfed infants (p < 0.05). Sex and body weight were not associated with EF. Despite the importance of EF towards total energy intake, no association with weight status was found.

Association between daily eating frequency and mortality in people with diabetes: Findings from NHANES 1999-2014

Background

Previous studies have shown that increasing the frequency of eating is beneficial in terms of cardiovascular metabolic risk factors; however, limited evidence is available for the association between daily eating frequency and mortality, especially in people with diabetes. Therefore, we aimed to explore the association between eating frequency and long-term mortality in populations with diabetes.

Methods

We selected 4,924 individuals suffering from diabetes (mean age: 57.77 years; 51.3% men) from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2014. Daily eating frequency was used as the exposure factor in this study. We extracted the mortality data from the National Death Index records and matched them with the population of NHANES. All participants were followed up from the date of getting enrolled in NHANES to 31 December 2015. Multivariate Cox proportional hazards regression, Kaplan-Meier survival curves, and restricted cubic spline were used to assess the associations between eating frequency and all-cause and cause-specific mortality among people with diabetes.

Results

During 34,950 person-years of follow-up, 1,121 deaths were documented, including 272 cardiovascular disease (CVD)-related deaths and 156 cancer-related deaths. After adjusting for confounding factors, the daily eating frequency was linearly inversely associated with all-cause and CVD-related mortality, and the HR (95% CIs) for per one-time increment of eating frequency was 0.88 (0.80-0.98) and 0.77 (0.63-0.93), respectively. Sensitivity analyses showed that the main results and statistical significance were still stable.

Conclusion

Higher eating frequency was independently related to lower all-cause and CVD-related mortality in people with diabetes, which can be used as a potential strategy for daily-diet management among populations suffering from diabetes.

Eating Patterns during Pregnancy and Postpartum and Their Association with Diet Quality and Energy Intake

This study investigates the relationship between meal-specific eating patterns during pregnancy and postpartum with maternal diet quality and energy intake. Participants in a prospective cohort study completed 24-h dietary recalls three times throughout both pregnancy and 1 year postpartum (n = 420). Linear regressions estimated the associations of eating frequency (number of daily main meals and eating occasions), meal and energy regularity (meal skipping and variation of daily energy intake), and intake timing patterns (distribution of energy intake throughout the day, derived using principal component analysis) with daily energy intake and diet quality (Healthy Eating Index-2015, calculated daily and overall, across both pregnancy and postpartum). Eating frequency was positively associated with energy intake and daily diet quality. Irregular meals were associated with lower energy intake in pregnancy but not postpartum and with lower pregnancy and postpartum diet quality. Energy irregularity was not associated with energy intake or diet quality. Higher postpartum diet quality was associated with a morning energy intake pattern (versus late morning/early afternoon or evening). Differences in these associations between pregnancy and postpartum suggest that efforts to support optimal energy intake and diet quality by modifying eating patterns may require specific strategies for pregnancy and postpartum.

Association between daily number of eating occasions with fasting glucose and insulin sensitivity in adults from families at high risk for type 2 diabetes in Europe: the Feel4Diabetes Study

OBJECTIVE

The aim of this study was to examine the association between the number of times one eats daily (termed eating occasions [EO]) with indices of glycemic control and insulin resistance (IR) in a large sample of adults from families at high risk for type 2 diabetes mellitus (T2DM) from six European countries. The study also considered sex and socioeconomic status (SES).

METHODS

Standardized questionnaires and procedures were used to assess sociodemographic characteristics, dietary intake, sedentary behavior, and anthropometric and biochemical indices. Univariate analysis of variance was used to investigate associations of daily EOs with fasting glucose (FG), fasting insulin (FI), and IR.

RESULTS

In 1552 adults (41.6 ± 7.2 y), three to four daily EOs rather than less than three were inversely associated with FG (β = -2.598; 95% confidence interval [CI], -4.521 to -0.675), independent of age, body mass index (BMI), dietary quality, and sedentary time. In women, three to four EOs per day were also associated with FG (β = -3.071; 95% CI to -5.573 to -0.570) independently of the mentioned confounders. In high SES participants, having more than four EOs per day had an inverse association with FI (β = -1.348; 95% CI to -2.583 to -0.114). No such associations were observed in men or in low SES participants.

CONCLUSION

In adults at high risk for T2DM, and especially in women, having three to four daily EOs was inversely associated with FG, whereas in high SES participants, more than four EOs was associated with FI. Future studies should further elucidate the underlying mechanisms and offer insight into the optimum number of daily EOs for the prevention of T2DM especially in men and in adults with low SES where the number of daily EOs was not found to be significantly related to glycemic indices.

Eating Speed, Eating Frequency, and Their Relationships with Diet Quality, Adiposity, and Metabolic Syndrome, or Its Components

Excess body weight is a major global health concern, particularly due to its associated increased health risks. Several strategies have been proposed to prevent overweight and obesity onset. In the past decade, it has been suggested that eating speed/rate and eating frequency might be related to obesity. The main aim of this narrative review was to summarize existing evidence regarding the impact of eating speed/rate and eating frequency on adiposity, metabolic syndrome (MetS), or diet quality (DQ). For this purpose, a literature search of observational and interventional trials was conducted between June and September 2020 in PubMed and Web of Sciences databases, without any data filters and no limitations for publication date. Results suggest that children and adults with a faster eating speed/rate may be associated with a higher risk of developing adiposity, MetS or its components. Furthermore, a higher eating frequency could be associated with diet quality improvement, lower adiposity, and lower risk of developing MetS or its components. Further interventional trials are warranted to clarify the mechanism by which these eating behaviors might have a potential impact on health.

Higher eating frequency is associated with lower adiposity and robust circadian rhythms: a cross-sectional study

BACKGROUND

Although overweight and obesity are assumed to arise from an energy imbalance, evidence has shown that the frequency and timing of meals are also potential risk factors for obesity. However, the lack of a consistent approach to define eating patterns relative to internal circadian rhythms limits the extent of these findings.

OBJECTIVES

The objective of this study was to investigate the association of the circadian pattern of energy intake with adiposity and with internal circadian rhythms.

METHODS

A total of 260 Spanish adults (aged 20-30 y; 78.1% women) were included in a 6-d cross-sectional study. Participants documented sleep and dietary intake within the study period. From these data, we evaluated the chronotype, eating patterns (meal timing, eating duration, and eating frequency), and we obtained the daily profile of energy intake. In addition, we evaluated the circadian pattern of wrist temperature (internal circadian rhythm marker). Circadian patterns of energy intake and wrist temperature were analyzed, and their association among them and with anthropometric variables and diet quality was studied.

RESULTS

The greater fragmentation of the circadian pattern of energy intake was associated with lower BMI (in kg/m2; -10.55; 95% CI: -16.96, -4.13; P = 0.001). In addition, a greater eating frequency (≥5 eating occasions/d) was significantly associated with lower BMI (-1.88; 95% CI: -3.27, -0.48) and higher energy intake after 20:00 (4.14% of kcal; 95% CI: 1.67, 7.16). Furthermore, a greater eating frequency was associated with lower fragmentation (P = 0.042) and greater stability of the circadian pattern of wrist temperature (P = 0.016).

CONCLUSIONS

The daily pattern of energy intake is associated with adiposity and robust circadian rhythms. Our results shed light on the relevance of eating frequency as a potential zeitgeber for the circadian system. Although more evidence is needed, eating frequency could be considered for future chrono-nutritional recommendations for the prevention of circadian misalignment and obesity.

Habitual Nightly Fasting Duration, Eating Timing, and Eating Frequency are Associated with Cardiometabolic Risk in Women

Nightly fasting duration (NFD) and eating timing and frequency may influence cardiometabolic health via their impact on circadian rhythms, which are entrained by food intake, but observational studies are limited. This 1-year prospective study of 116 US women (33 ± 12y, 45% Hispanic) investigated associations of habitual NFD and eating timing and frequency with cardiovascular health (CVH; American Heart Association Life’s Simple 7 score) and cardiometabolic risk factors. NFD, eating timing and frequency, and nighttime eating levels were evaluated from 1-week electronic food records completed at baseline and 1 y. In multivariable-adjusted linear regression models, longer NFD was associated with poorer CVH (β = −0.22, p = 0.016 and β = −0.22, p = 0.050) and higher diastolic blood pressure (DBP) (β = 1.08, p < 0.01 and β = 1.74, p < 0.01) in cross-sectional and prospective analyses, respectively. Later timing of the first eating occasion at baseline was associated with poorer CVH (β = −0.20, p = 0.013) and higher DBP (β = 1.18, p < 0.01) and fasting glucose (β = 1.43, p = 0.045) at 1 y. After adjustment for baseline outcomes, longer NFD and later eating times were also associated with higher waist circumference (β = 0.35, p = 0.021 and β = 0.27, p < 0.01, respectively). Eating frequency was inversely related to DBP in cross-sectional (β = −1.94, p = 0.033) and prospective analyses (β = −3.37, p < 0.01). In cross-sectional analyses of baseline data and prospective analyses, a higher percentage of daily calories consumed at the largest evening meal was associated with higher DBP (β = 1.69, p = 0.046 and β = 2.32, p = 0.029, respectively). Findings suggest that frequent and earlier eating may lower cardiometabolic risk, while longer NFD may have adverse effects. Results warrant confirmation in larger multi-ethnic cohort studies with longer follow-up periods.

Daily Eating Frequency in US Adults: Associations with Low-Calorie Sweeteners, Body Mass Index, and Nutrient Intake (NHANES 2007-2016)

Studies of relationships between eating frequency and/or timing and energy intake have not examined associations with low-calorie sweeteners (LCS). We assessed the frequency of eating behavior related to LCS consumption emphasizing timing, calorie intake, and body mass index (BMI) among United States (US) adults aged ≥19 years. Using the National Health and Nutrition Examination Survey (NHANES) 2007-2016, we defined eating episodes as food and/or beverage intake within 15 min of one another over the first 24-h dietary recall. We coded items ingested during episodes (n = 136,938) and assessed LCS presence using US Department of Agriculture (USDA) food files. Episode analysis found intakes of foods only (27.4%), beverages only (29.5%), and foods with beverages (43.0%). LCS items were consumed without concurrent calories from other sources in fewer than 2.7% of all episodes. Within participants having normal weight (29.4%), overweight (33.6%) and obese (37.1%) BMIs, LCS consumers (35.2% overall) evidenced: more episodes/day; and fewer: calories, carbohydrates, fats, and protein per episode. Per person, those consuming LCS had lower total calories and higher fiber intake per day. LCS consumption was associated with higher BMI. Number of eating episodes/day and longer hours when eating episodes occurred were also consistently associated with higher BMI. Consuming LCS did not modify these relationships. These results did not show that LCS consumption was associated with increased caloric intake from other dietary sources.

Associations of Number of Daily Eating Occasions with Type 2 Diabetes Risk in the Women's Health Initiative Dietary Modification Trial

BACKGROUND

Over 23 million Americans have type 2 diabetes (T2D). Eating habits such as breakfast consumption, time-restricted eating, and limiting daily eating occasions have been explored as behaviors for reducing T2D risk, but prior evidence is inconclusive.

OBJECTIVES

Our objectives were to examine associations between number of daily eating occasions and T2D risk in the Women's Health Initiative Dietary Modification Trial (WHI-DM) and whether associations vary by BMI, age, or race/ethnicity.

METHODS

Participants were postmenopausal women in the WHI-DM who comprised a 4.6% subsample completing 24-h dietary recalls (24HRs) at years 3 and 6 as part of trial adherence activities (n = 2159). Numbers of eating occasions per day were obtained from the year 3 24HRs, and participants were grouped into approximate tertiles as 1-3 (n = 795), 4 (n = 713), and ≥5 (n = 651) daily eating occasions as the exposure. Incident diabetes was self-reported on semiannual questionnaires as the outcome.

RESULTS

Approximately 15% (15.4%, n = 332) of the WHI-DM 24HR cohort reported incident diabetes at follow-up. Cox proportional hazards regression tested associations of eating occasions with T2D adjusted for neighborhood socioeconomic status, BMI, waist circumference, race/ethnicity, family history of T2D, recreational physical activity, Healthy Eating Index-2005, 24HR energy intake, and WHI-DM arm. Compared with women reporting 1-3 meals/d, those consuming 4 meals/d had a T2D HR = 1.38 (95% CI: 1.03, 1.84) without further increases in risk for ≥5 meals/d. In stratified analyses, associations for 4 meals/d compared with 1-3 meals/d were stronger in women with BMI <30.0 kg/m2 (HR = 1.55; 95% CI: 1.00, 2.39) and women aged ≥60 (HR = 1.61; 95% CI: 1.11, 2.33).

CONCLUSIONS

Four meals per day compared with 1-3 meals/d was associated with increased risk of T2D in postmenopausal women, but no dose-response effect was observed for additional eating occasions. Further studies are needed to understand eating occasions in relation to T2D risk.

More Frequent Intake of Regular Meals and Less Frequent Snacking Are Weakly Associated with Lower Long-Term Gains in Body Mass Index and Fat Mass in Middle-Aged Men and Women

BACKGROUND

Few studies have examined the relationship between eating frequency and long-term change in body weight, and the results have been inconsistent.

OBJECTIVE

We examined the associations between eating frequency and 6-y changes in body mass index (BMI; in kg/m2), fat mass, fat-free mass, body fat percentage, and waist circumference.

METHODS

The study consisted of Danish men (n = 1080) and women (n = 1044) aged 35-67 y with repeated measures of eating frequency, adiposity, and covariates during 11 y. Multiple linear regression was used to assess the associations between baseline eating frequency and subsequent change in BMI, fat mass, fat-free mass, fat percentage, and waist circumference, as well as the association between initial change in eating frequency and subsequent change in the same outcomes.

RESULTS

Total baseline eating frequency was not associated with change in outcomes. However, when separately examining regular meals and snacks, each additional daily meal was associated with a subsequent 6-y change in BMI of -0.14 (95% CI: -0.27, -0.00). Similar tendencies of inverse associations were found for change in fat mass (P = 0.04), fat-free mass (P = 0.07), and waist circumference (P = 0.05). We found no association between initial change in total eating frequency and subsequent change in outcomes. However, each additional daily regular meal after 5 y was associated with a subsequent 6-y change in BMI of -0.16 (95% CI: -0.30, -0.01). Inverse associations were also seen for fat (P = 0.04) and fat-free mass (P = 0.05). In contrast, an increase in daily frequency of snacking was associated with an increase in fat mass (P = 0.04) and fat percentage (P = 0.02).

CONCLUSIONS

Our results indicate that total frequency of eating has little or no influence on adiposity among middle-aged Danish men and women. Consumption of regular meals, but not snack consumption, showed a weak inverse association with longitudinal gains in BMI.

Irregular eating patterns associate with hypomanic symptoms in bipolar disorders

Objective: We present novel dimensional methods to describe the timing of eating in psychopathology. We focused on the relationship between current mood in bipolar disorder (BD) and the stability of the temporal pattern of daily eating events. Methods: Consenting BD patients (n = 69) from an outpatient, tertiary care clinic completed hourly charts of mood and eating for two weeks. Mood was also evaluated with Montgomery-Åsberg Depression Rating Scale (MADRS) and Young Mania Rating Scale (YMRS). Results: Illustrative displays, or eatograms, enabling visualization of all recorded eating events were used to guide assessment of the temporal structure of eating across the two week assessment period. We computed indices to quantify irregularities in timing of eating, namely I^FRQ, I^TIM and I^INT for the variability of frequency, timing, and interval of eating events, respectively. In this cohort, irregular temporal pattern of eating correlated with hypomanic symptoms (YMRS with I^FRQ, Spearman rank order rh = 0.28, p = .019, with I^TIM, rh = 0.44, p < .001, and with I^INT rh = 0.38, p = .001), but not depressive symptoms or anthropometric measures. Conclusions: Our data suggest a link between the instability of the temporal order of daily eating and mood. The dimensional measures for eating pattern introduced here enable future investigations of correlations with psychopathology.

Eating Frequency Is Not Associated with Obesity in Chinese Adults

The prevalence of overweight and obesity has been increasing globally. Recent studies suggest that eating frequency (EF) might be a factor influencing the development of overweight and obesity. This study aims to explore the association between eating frequency and obesity in Chinese adults. A cross-sectional study was conducted in Wuhan, China, from March to June 2016. A self-administered questionnaire and 24-h dietary recall were used to collect data on sociodemographic variables, lifestyle factors, nutrition knowledge, and eating frequency. Participants were divided into four groups according to eating frequency and meal timing: traditional time pattern (TTP), traditional time plus late snack pattern (TTLSP), irregular time pattern (ITP), and all-day pattern (ADP). We performed the chi-squared test and multiple logistic regression to assess associations among variables using JMP statistical software version 14.0.0 (SAS Institute Inc., Cary, NC, USA). Respondents were Chinese adults (N = 2290; range 29⁻74 years; 1162 men). Lower education level, higher food budget, and lower nutrition knowledge were associated with higher likelihood of irregular EF patterns (TTLSP, ITP, or ADP). Men, non-smokers, and participants with less physical activity, lower education level, or lower nutrition knowledge were more likely to be obese. Body mass index (BMI) categorization was significantly different among EF pattern groups (χ² = 25.40, p = 0.003); however, this association was no longer significant in the regression model after adjustment for age, sex, education, smoking, food budget, nutrition knowledge, and physical activity. Thus, EF is not associated with obesity in Chinese adults.

Differences over 12 Years in Food Portion Size and Association with Excess Body Weight in the City of São Paulo, Brazil

Although changes in Brazilian diet have occurred over the last decades, there is no evidence about differences in food portion sizes (FPS) over time. Therefore, we aimed to evaluate the association of FPS with excess body weight (EBW), and to monitor differences in the population from São Paulo, Brazil, from 2003 to 2015. Data came from three cross-sectional population-based studies with 5270 individuals aged ≥12 years in 2003, 2008, and 2015. Dietary data were obtained from 24-h recalls. Logistic regression models were used to evaluate the association between FPS and EBW. Over the years, there was a diverse variation in FPS, with an increase in some groups (white meat, salted snacks, coffee/tea, eggs) and decrease in others (rice, red meat, sweets, pasta, sandwiches, cold cuts). The percentage of people reporting the intake of six food groupings (rice, white meat, sweets, fruits, commercial juices, toasts/biscuits) increased in the period. In this population, EBW was associated with larger FPS of 11 of the 30 food groupings investigated (cold cuts, fried snacks, fruit and commercial juices, pizza, red meat, rice, salted snacks, soft drinks, soups, sugar). These findings could support future interventions and policies for optimal food intake in Brazil.

Longitudinal association between eating frequency and hemoglobin A1c and serum lipids in diabetes in the SEARCH for Diabetes in Youth study

BACKGROUND

Few studies have evaluated the prospective association of eating frequency with HbA1c levels and cardiovascular disease risk markers among youth with diabetes.

OBJECTIVE

To examine the 5-year longitudinal association of eating frequency with HbA1c and serum lipid levels among youth with type 1 diabetes (T1D) or type 2 diabetes (T2D).

METHODS

One-thousand and forty-nine youth (≥10-year old) with incident T1D (n = 821) or T2D (n = 228) who participated in the SEARCH for Diabetes in Youth study were included. Eating frequency (≤3, 4-5, or 6-10 times/d) measured at baseline and follow-up visits was related to HbA1c and serum lipid levels measured repeatedly over 5 years.

RESULTS

Increased eating frequency was associated with larger increases in HbA1c among youth T1D. For example, for youth with T1D who ate ≤3 times/d at the outset and ate 6-10 times/d 5 years later, the longitudinal model predicted greater absolute increases in HbA1c (2.77%); whereas for youth with T1D who ate 6-10 times/d at the outset and ate ≤3 times/d 5 years later, the model predicted lesser absolute increases in HbA1c (1.33%). Eating frequency was not associated with changes in serum lipid levels among youth with T1D or T2D.

CONCLUSIONS

Youth with T1D who increased their eating frequency vs those who decreased it had larger increases in HbA1c over 5 years.

Complex interactions of circadian rhythms, eating behaviors, and the gastrointestinal microbiota and their potential impact on health

Human health is intricately intertwined with the composition and function of the trillions of microorganisms that make up the gastrointestinal (GI) microbiome. The GI microbiome is essentially a microbial organ that provides metabolic, immunologic, and protective functions for the host. Habitual diet, changes in macronutrient composition, and consumption of nondigestible dietary fibers have all been shown to impact the human GI microbiome. Intriguingly, the impact of diet on the microbiome may be related not only to what humans eat but also to the timing of food consumption. Emerging preclinical research suggests that gut microbes experience diurnal rhythms, and the health effects of eating patterns, including time-restricted feeding and meal frequency, may be related to the GI microbiome. Herein, the complex connections among circadian rhythms, eating behaviors, the GI microbiome, and health are reviewed, highlighting the need for additional translational research in this area.

Time of day and eating behaviors are associated with the composition and function of the human gastrointestinal microbiota

Background: Preclinical research has shown that the gastrointestinal microbiota exhibits circadian rhythms and that the timing of food consumption can affect the composition and function of gut microbes. However, there is a dearth of knowledge on these relations in humans.Objective: We aimed to determine whether human gastrointestinal microbes and bacterial metabolites were associated with time of day or behavioral factors, including eating frequency, percentage of energy consumed early in the day, and overnight-fast duration.Design: We analyzed 77 fecal samples collected from 28 healthy men and women. Fecal DNA was extracted and sequenced to determine the relative abundances of bacterial operational taxonomic units (OTUs). Gas chromatography-mass spectroscopy was used to assess short-chain fatty acid concentrations. Eating frequency, percentage of energy consumed before 1400, and overnight-fast duration were determined from dietary records. Data were analyzed by linear mixed models or generalized linear mixed models, which controlled for fiber intake, sex, age, body mass index, and repeated sampling within each participant. Each OTU and metabolite were tested as the outcome in a separate model.Results: Acetate, propionate, and butyrate concentrations decreased throughout the day (P = 0.006, 0.04, and 0.002, respectively). Thirty-five percent of bacterial OTUs were associated with time. In addition, relations were observed between gut microbes and eating behaviors, including eating frequency, early energy consumption, and overnight-fast duration.Conclusions: These results indicate that the human gastrointestinal microbiota composition and function vary throughout the day, which may be related to the circadian biology of the human body, the microbial community itself, or human eating behaviors. Behavioral factors, including timing of eating and overnight-fast duration, were also predictive of bacterial abundances. Longitudinal intervention studies are needed to determine causality of these biological and behavioral relations. This trial was registered at clinicaltrials.gov as NCT01925560.

Increased Eating Frequency Is Associated with Lower Obesity Risk, But Higher Energy Intake in Adults: A Meta-Analysis

Body weight is regulated by energy intake which occurs several times a day in humans. In this meta-analysis, we evaluated whether eating frequency (EF) is associated with obesity risk and energy intake in adults without any dietary restriction. Experimental and observational studies published before July 2015 were selected through English-language literature searches in several databases. These studies reported the association between EF and obesity risk (odd ratios, ORs) in adults who were not in dietary restriction. R software was used to perform statistical analyses. Ten cross-sectional studies, consisting of 65,742 participants, were included in this analysis. ORs were considered as effect size for the analysis about the effect of EF on obesity risk. Results showed that the increase of EF was associated with 0.83 time lower odds of obesity (i.e., OR = 0.83, 95% confidence intervals (CI) 0.70-0.99, p = 0.040). Analysis about the effect of EF on differences in participants' energy intake revealed that increased EF was associated with higher energy intake (β = 125.36, 95% CI 21.76-228.97, p = 0.017). We conclude that increased EF may lead to lower obesity risk but higher energy intake. Clinical trials are warranted to confirm these results and to assess the clinical practice applicability.

Higher Eating Frequency Does Not Decrease Appetite in Healthy Adults

BACKGROUND

Consumption of small, frequent meals is suggested as an effective approach to control appetite and food intake and might be a strategy for weight loss or healthy weight maintenance. Despite much speculation on the topic, scientific evidence is limited to support such a relation in the absence of changes to diet composition.

OBJECTIVE

We examined the effects of high compared with low eating frequency (EF) on self-reported appetite as a secondary outcome in a controlled trial.

METHODS

We conducted a randomized, crossover intervention trial in 12 participants (4 men, 8 women) who completed 2 isocaloric 3-wk intervention phases of low EF (3 eating occasions/d) compared with high EF (8 eating occasions/d). On the last morning of each study phase, participants completed a 4-h appetite testing session. During the appetite testing session, participants completing the low EF phase consumed a meal at 0800. Participants completing the high EF intervention consumed the same meal spread evenly over 2 eating occasions at 0800 and 1030. Standardized ratings of hunger, desire to eat, fullness, thirst, and nausea were completed every 30 min with the use of paper-and-pencil semianchored 100-mm visual analog scales. A composite appetite score was calculated as the mean of hunger, desire to eat, and the inverse of fullness (calculated as 100-fullness rating). Linear regression analysis compared ratings between low EF and high EF conditions.

RESULTS

The mean composite appetite score was higher in the high EF condition for the total testing period (baseline through 1200) (P < 0.05) and for the time period from baseline through 1030 (P < 0.001).

CONCLUSION

The results from this study in 12 healthy adults do not support the popularized notion that small, frequent meals help to decrease overall appetite. This trial was registered at clinicaltrials.gov as NCT02548026.

Adults

BACKGROUND

Evidence of the association between eating frequency (EF) and adiposity is inconsistent.

OBJECTIVE

With the use of data from the NHANES 2003-2012, this cross-sectional study examined the associations between EF, meal frequency (MF), and snack frequency (SF) and overweight/obesity and central obesity.

METHODS

Dietary intake was assessed with the use of two 24-h dietary recalls in 18,696 US adults ≥20 y of age. All eating occasions providing ≥50 kcal of energy were divided into meals or snacks on the basis of contribution to energy intake (≥15% or <15%), self-report, and time (0600-1000, 1200-1500, 1800-2100, or other). Multivariable logistic regression was used to compute ORs and 95% CIs.

RESULTS

When analyzed without adjustment for the ratio of energy intake to estimated energy requirement (EI:EER), all measures of EF, MF, and SF showed inverse or null associations. After adjustment for EI:EER, however, EF was positively associated with overweight/obesity (body mass index ≥25 kg/m2) and central obesity (waist circumference ≥102 cm in men and ≥88 cm in women). Compared with the lowest category (≤3 times/d), the OR (95% CI) for overweight/obesity in the highest category (≥5 times/d) was 1.54 (1.23, 1.93) in men (P-trend = 0.003) and 1.45 (1.17, 1.81) in women (P-trend = 0.001). The corresponding value for central obesity was 1.42 (1.15, 1.75) in men (P-trend = 0.002) and 1.29 (1.05, 1.59) in women (P-trend = 0.03). The self-report-based MF and time-based MF were positively associated with overweight/obesity, central obesity, or both, although MF based on energy contribution showed no associations. There were positive associations for all SF measures in men and for the energy-contribution-based SF in women.

CONCLUSIONS

This cross-sectional study suggests that higher EF, MF, and SF are associated with an increased likelihood of overweight/obesity and central obesity in US adults. Prospective studies are needed to confirm the associations observed in this study.

The role of eating frequency on relative weight in urban school-age children

BACKGROUND

The role of eating frequency on relative weight in childhood is not well understood.

OBJECTIVE

To clarify this relationship by assessing the cross-sectional and prospective relationships of weekday eating frequency with BMI z-score (BMIz) and change in BMIz in a sample of schoolchildren.

METHODS

Eating frequency, the average number of reported daily eating occasions, was assessed using two weekday 24-h diet recalls. BMIz was measured at baseline, 6 months and 1 year in 155 urban schoolchildren, ages 9-15 years. Multiple linear regression models were used.

RESULTS

Cross-sectional analyses at baseline suggest that BMIz was 0.23 units lower for each additional reported eating occasion (regression coefficient = -0.23; 95% confidence interval [CI]: -0.44, -0.07). From baseline to 6 months, BMIz increased by 0.03 units for each additional reported eating occasion (regression coefficient = 0.03; 95% CI: 0.01, 0.05). This relationship was no longer statistically significant at 1 year (regression coefficient = 0.01; 95% CI: -0.01, 0.03).

CONCLUSIONS

The findings suggest that the relationship of eating frequency with BMIz differs from that of change in BMIz. This difference may be due to methodological deficiencies of cross-sectional studies, challenges of dietary assessment or differences in eating patterns among normal and overweight youth. Controlled trials are needed to further clarify this relationship.

Characterizing eating patterns: a comparison of eating occasion definitions

BACKGROUND

To date, many approaches have been used to define eating occasions (EOs). A standard definition for EOs is required to facilitate further research.

OBJECTIVE

In this study, we examined the influence of differing definitions of EOs on the characterization of eating patterns.

DESIGN

Cross-sectional dietary data from two 24-h recalls collected during the 2011-12 Australian National Nutrition and Physical Activity Survey (n = 5242 adults, aged ≥19 y) were analyzed. Eight definitions were applied: participant-identified, time-of-day, and 6 neutral definitions (individual EOs separated by different time intervals and/or an additional energy criterion of 210 kJ). Frequency of and total energy intake from meals, snacks, and all EOs were estimated, as appropriate. Differences were tested by using F tests, stratified by sex and age group. Agreement between different definitions of meal and snack frequencies was assessed by using intraclass correlation coefficients (ICCs). For each definition, linear regression was used to estimate the proportion of variance in total energy intake (kJ) and amount of food intake (g) predicted by frequency of EOs and meals and snacks.

RESULTS

Among both sexes and across all age groups, mean frequencies of meals differed between the participant-identified and time-of-day definitions (mean difference range = 0.1-0.3; P < 0.001). There were statistically significant differences between mean frequencies of EOs across the 6 neutral definitions (P < 0.001). There was good agreement for snacks (men: ICC = 0.89; women: ICC = 0.87) but not meal frequencies (men: ICC = 0.38; women: ICC = 0.36) between the participant-identified and time-of-day definitions. The neutral definition (15-min time interval plus energy criterion) best predicted variance in total energy intake (R(2) range = 19.3-27.8).

CONCLUSIONS

Different approaches to the definition of EOs affect how eating patterns are characterized, with the neutral definition best predicting variance in total energy intake. Further research that examines how different EO definitions affect associations with health outcomes is needed to develop consensus on a standard EO definition.

Within-person comparison of eating behaviors, time of eating, and dietary intake on days with and without breakfast: NHANES 2005-2010

BACKGROUND

Breakfast omission is known to be associated with lower 24-h energy intake. However, little is known about downstream eating behaviors subsequent to skipping breakfast in free-living individuals.

OBJECTIVE

We replicated the traditional crossover design of nutrition studies in a naturalistic setting to compare within-person differences in self-reported eating behaviors, energy intake, and other dietary characteristics of individuals on a day that included breakfast with a day that omitted breakfast.

DESIGN

We used cross-sectional dietary data for 2132 adult respondents who reported breakfast in only one of 2 dietary recalls in the NHANES 2005-2010. Dietary outcomes examined included meal- and snack-eating behaviors, clock time of eating episodes, and intakes of energy, macronutrients, and food groups. Regression methods accounted for replicate diet measurements, covariates, and survey-design characteristics.

RESULTS

The breakfast meal provided a mean of 508 kcal in men and 374 kcal in women, but differences in 24-h energy intakes between the breakfast and no-breakfast day were 247 and 187 kcal, respectively. Energy intakes at the lunch meal were higher on the no-breakfast day (202 kcal in men and 121 kcal in women), and the reported time of lunch was ∼35 min earlier. The energy contribution of dinner or its reported time did not differ. A higher number of energy-adjusted servings of fruit and whole grains were reported on the breakfast day, but the energy and macronutrient density of reported foods were not different.

CONCLUSIONS

In free-living American adults, the eating time for lunch was earlier, and the lunch meal provided more energy on the no-breakfast day than on the breakfast day. Although the quality of dietary selections reflected in the energy and macronutrient density of a day's intake did not differ between the breakfast and the no-breakfast day, breakfast skippers may need encouragement to consume fruit and whole grains at other eating episodes.

Eating Frequency, Food Intake, and Weight: A Systematic Review of Human and Animal Experimental Studies

Eating frequently during the day, or "grazing," has been proposed to assist with managing food intake and weight. This systematic review assessed the effect of greater eating frequency (EF) on intake and anthropometrics in human and animal experimental studies. Studies were identified through the PubMed electronic database. To be included, studies needed to be conducted in controlled settings or use methods that carefully monitored food intake, and measure food intake or anthropometrics. Studies using human or animal models of disease states (i.e., conditions influencing glucose or lipid metabolism), aside from being overweight or obese, were not included. The 25 reviewed studies (15 human and 10 animal studies) contained varying study designs, EF manipulations (1-24 eating occasions per day), lengths of experimentation (230 min to 28 weeks), and sample sizes (3-56 participants/animals per condition). Studies were organized into four categories for reporting results: (1) human studies conducted in laboratory/metabolic ward settings; (2) human studies conducted in field settings; (3) animal studies with experimental periods <1 month; and (4) animal studies with experimental periods >1 month. Out of the 13 studies reporting on consumption, 8 (61.5%) found no significant effect of EF. Seventeen studies reported on anthropometrics, with 11 studies (64.7%) finding no significant effect of EF. Future, adequately powered, studies should examine if other factors (i.e., disease states, physical activity, energy balance and weight status, long-term increased EF) influence the relationship between increased EF and intake and/or anthropometrics.

Dietary sodium intake in young Korean adults and its relationship with eating frequency and taste preference

Dietary sodium intake is considered one of the major causal factors for hypertension. Thus, to control the increase of blood pressure and reduce the risk of hypertension-related clinical complications, a reduction in sodium intake is recommended. The present study aimed at determining the association of dietary sodium intake with meal and snack frequency, snacking time, and taste preference in Korean young adults aged 20-26 years, using a 125-item dish-frequency questionnaire. The mean dietary sodium intakes of men and women were 270.6 mmol/day and 213.1 mmol/day, which were approximately 310% and 245% of the daily sodium intake goal for Korean men and women, respectively. Dietary sodium intake was positively correlated with systolic blood pressure in the total group, and BMI in the total and men-only groups. In the total and men-only groups, those who consumed meals more times per day consumed more dietary sodium, but the number of times they consumed snacks was negatively correlated with dietary sodium intake in the total, men-only, and women-only groups. In addition, those who consumed snacks in the evening consumed more sodium than those who did so in the morning in the men-only group. The sodium intake was also positively associated with preference for salty and sweet taste in the total and women-only groups. Such a high intake of sodium in these young subjects shows that a reduction in sodium intake is important for the prevention of hypertension and related diseases in the future.

Eating frequency and overweight and obesity in children and adolescents: a meta-analysis

OBJECTIVES

To determine the effect of eating frequency on body weight status in children and adolescents.

METHODS

In this meta-analysis, original observational studies published to October 2011 were selected through a literature search in the PubMed database. The reference list of the retrieved articles was also used to identify relevant articles; researchers were contacted when needed. Selected studies were published in English, and they reported on the effect of eating frequency on overweight/obesity in children and adolescents. Pooled effect sizes were calculated using a random effects model.

RESULTS

Ten cross-sectional studies and 1 case-control study (21 substudies in total), comprising 18 849 participants (aged 2-19 years), were included in the analysis. Their combined effect revealed that the highest category of eating frequency, as compared with the lowest, was associated with a beneficial effect regarding body weight status in children and adolescents (odds ratio [OR] = 0.78, log OR = -0.24, 95% confidence interval [CI] -0.41 to -0.06). The observed beneficial effect remained significant in boys (OR = 0.76, log OR = -0.27, 95% CI -0.47 to -0.06), but not in girls (OR = 0.96, log OR = -0.04, 95% CI -0.40 to 0.32) (P for sex differences = 0.14).

CONCLUSIONS

Higher eating frequency was associated with lower body weight status in children and adolescents, mainly in boys. Clinical trials are warranted to confirm this inverse association, evaluate its clinical applicability, and support a public health recommendation; more studies are also needed to further investigate any sex-related differences, and most importantly, the biological mechanisms.

Eating patterns and nutritional characteristics associated with sleep duration

OBJECTIVE

To identify major meal and snack eating patterns, and examine their relationships with sleep duration.

DESIGN

The analyses included 27 983 participants in a prospective cohort study of women aged 35 to 74 years in the USA or Puerto Rico.

RESULTS

The principal component analysis of eight meal and snack frequency items at different times across the day yielded two major eating patterns: (i) eating during conventional eating hours (defined as times from breakfast to dinner); and (ii) dominance of snacks over meals. Comparing the identified eating patterns among women with varying sleep duration (<5, 5-5·9, 6-6·9, 7-7·9, 8-8·9, 9-9·9 and ≥10 h daily), the tendency for eating during conventional eating hours decreased with decreasing sleep duration: adjusted mean score of -0·54 (95% CI -0·68, -0·41) in women sleeping for <5 h daily v. 0·08 (95% CI 0·06, 0·11) among those with 7-7·9 h of sleep daily. The extent of snack dominance over meals increased in women with shorter sleep. Women with long (≥10 h) sleep duration had eating patterns similar to those with short (<6 h) sleep duration. Lower tendency for eating during conventional eating hours and greater snack dominance over meals were also related to higher intakes of fat and sweets for energy and lower intakes of fruits and vegetables.

CONCLUSIONS

Disrupted eating patterns and diet of poor nutritional quality may exacerbate the development of obesity and metabolic diseases in habitual short and very long sleepers.

Secular trends in patterns of self-reported food consumption of adult Americans: NHANES 1971-1975 to NHANES 1999-2002

BACKGROUND

The contributors to trends in increasing prevalence of obesity in the US population are poorly understood.

OBJECTIVE

We examined secular trends in food consumption behaviors to understand their possible contribution to increasing energy intakes and adiposity in the American population.

DESIGN

We used dietary data from 4 consecutive National Health and Nutrition Examination Surveys (NHANES) to examine trends (1971-2002) in frequency of eating episodes, meal and snack consumption, quantity of food consumed, and the energy density of foods reported by adult Americans (n = 39 094). Logistic and linear regression methods were used to adjust for multiple covariates and survey design.

RESULTS

The reported number of all eating episodes increased slightly in women from 4.90 in 1971-1975 to 5.04 in 1999-2002 (P for trend = 0.002). The amount (in g) of foods and beverages consumed, the energy density of foods, and energy intake per eating episode increased, but the mention of breakfast declined in both sexes (P for trend < 0.0001). The observed trends in mention of a snack (in men) and percentage of energy from evening food intake (in women) were downward. The amount (in g) of foods and their energy density were independent positive correlates of obesity in combined data from all surveys (P for trend < 0.0001).

CONCLUSIONS

Our results do not support large increases in eating frequency, snacking, or evening eating by the American population from 1971 to 2002. The quantity of foods and their energy density increased beginning in NHANES III (1988-1994) with trajectories roughly parallel to the rates of prevalence of obesity in the US population. However, we urge cautious interpretation of these results because of concurrent changes in dietary methods during this period.