Late bedtime combined with more screen time before bed increases the risk of obesity and lowers diet quality in Spanish children.

This cross-sectional study aimed to investigate whether the combination of bedtime and screen time (ST) before bed were associated with obesity and diet quality in toddlers and school-aged children. Parents reported children's bedtimes and ST before bed (0 min, 1-30 min, >30 min). We then defined bed + screen time behavior using bedtime median cut-offs (early [EB] or late [LB]) and ST responses, resulting in four groups: EB-0'ST, EB ≤ 30'ST/LB-0'ST, EB > 30'ST/LB ≤ 30'ST, and LB > 30'ST. For all participants (n = 1133; 5.4 ± 2.7 years, 49.7% girls, 51.9% school-aged) we evaluated body mass index (BMI), diet quality, sleep-related variables, physical activity, and health-related quality of life (HRQoL). Outcome variables were compared across bed + screen time behavior groups, stratified by age group (toddlers and school-aged children) using general linear models for continuous variables, as well as chi-squared tests or logistic regressions for categorical variables. Additionally, we calculated linear p-trends. Analyses were adjusted for sociodemographic variables, BMI, and physical activity (unless the variable was tested). The results showed that toddlers and school-aged children in the LB ≥ 30'ST group were more likely to have overweight/obesity (OR: 3.42 [95%CI:1.41,8.26] and OR: 2.53 [95%CI:1.10,5.03], respectively) than those in the EB-0'ST group. Additionally, toddlers and school-aged children in the EB > 30'ST/LB ≤ 30'ST and LB > 30'ST groups showed significantly lower adherence to the Mediterranean diet compared to the other groups (p < 0.001). Regarding sleep-related outcomes, we observed that the combination of LB and more ST was associated with poorer sleep quality and shorter sleep duration in toddlers and school-aged children (p < 0.001). These findings emphasize the importance of promoting earlier bedtimes and limiting ST before bed as part of obesity prevention strategies for children. Furthermore, such intervention could benefit the quality of children's diet and overall lifestyle.

Are Emotional Eating and Other Eating Behaviors the Missing Link in the Relationship between Inadequate Sleep and Obesity? A Systematic Review.

Evidence is emerging to explain that the relationship between inadequate sleep and obesity could be influenced by emotional eating and other eating behaviors such as disinhibition. Therefore, our aim was to conduct a systematic review to analyze the potential role of emotional eating and other eating behaviors in the relationship between inadequate sleep and obesity. We conducted a comprehensive search on 2 databases (Medline and Scopus) looking for records from 1 January 2011 until 31 December 2022 without language restrictions. Cross-sectional, longitudinal, and interventional studies were included if they assessed the association between sleep and emotional eating, as well as the role of emotional eating on the relationship between inadequate sleep and obesity. Secondary outcomes included studies analyzing the link between sleep and other eating behaviors as well as their role in the sleep-obesity relationship. Our results showed that emotional eating and disinhibition play a significant role in the relationship between inadequate sleep and obesity, especially in women. Furthermore, we provide evidence of other eating behaviors (e.g., external eating, eating competence, and hunger), which are also associated with poor sleep outcomes. However, these behaviors do not seem to be determinants of the association between sleep and obesity. In conclusion, our results suggest that individuals with inadequate sleep who are prone to emotional eating and/or disinhibition may require tailored approaches for obesity prevention and treatment.

Relative Validity and Reliability of the Remind App as an Image-Based Method to Assess Dietary Intake and Meal Timing in Young Adults.

Image-based dietary records have been validated as tools to evaluate dietary intake. However, to determine meal timing, previous studies have relied primarily on image-based smartphone applications without validation. Noteworthy, the validation process is necessary to determine how accurately a test method measures meal timing compared with a reference method over the same time period. Thus, we aimed to assess the relative validity and reliability of the Remind® app as an image-based method to assess dietary intake and meal timing. For this purpose, 71 young adults (aged 20-33 years, 81.7% women) were recruited for a 3-day cross-sectional study, where they completed a 3-day image-based record using the Remind app (test method) and a 3-day handwritten food record (reference method). The relative validity of the test method versus the reference method was assessed using multiple tests including Bland-Altman, % difference, paired t-test/Wilcoxon signed-rank test, Pearson/Spearman correlation coefficients, and cross-classification. We also evaluated the reliability of the test method using an intra-class correlation (ICC) coefficient. The results showed that, compared to the reference method, the relative validity of the test method was good for assessing energy and macronutrient intake, as well as meal timing. Meanwhile, the relative validity of the test method to assess micronutrient intake was poor (p < 0.05) for some micronutrients (iron, phosphorus, potassium, zinc, vitamins B1, B2, B3, B6, C, and E, and folates) and some food groups (cereals and grains, legumes, tubers, oils, and fats). Regarding the reliability of an image-based method to assess dietary intake and meal timing, results ranged from moderate to excellent (ICC 95% confidence interval [95% CI]: 0.50-1.00) for all nutrients, food groups (except oils and fats, which had low to moderate reliability), and meal timings. Thus, the results obtained in this study provide evidence of the relative validity and reliability of image-based methods to assess dietary intake (energy, macronutrients, and most food groups) and meal timing. These results open up a new framework for chrononutrition, as these methods improve the quality of the data collected and also reduce the burden on users to accurately estimate portion size and the timing of meals.

Skin Temperature Circadian Rhythms and Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Role of Endothelin-1 in the Vascular Tone Dysregulation.

There is accumulating evidence of autonomic dysfunction in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS); however, little is known about its association with circadian rhythms and endothelial dysfunction. This study aimed to explore the autonomic responses through an orthostatic test and analysis of the peripheral skin temperature variations and vascular endothelium state in ME/CFS patients. Sixty-seven adult female ME/CFS patients and 48 healthy controls were enrolled. Demographic and clinical characteristics were assessed using validated self-reported outcome measures. Postural changes in blood pressure, heart rate, and wrist temperature were recorded during the orthostatic test. Actigraphy during one week was used to determine the 24-h profile of peripheral temperature and activity. Circulating endothelial biomarkers were measured as indicators of endothelial functioning. Results showed that ME/CFS patients presented higher blood pressure and heart rate values than healthy controls in the supine and standing position (p < 0.05 for both), and also a higher amplitude of the activity rhythm (p < 0.01). Circulating levels of endothelin-1 (ET-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly higher in ME/CFS (p < 0.05). In ME/CFS, ET-1 levels were associated with the stability of the temperature rhythm (p < 0.01), and also with the self-reported questionnaires (p < 0.001). This suggests that ME/CFS patients exhibited modifications in circadian rhythm and hemodynamic measures, which are associated with endothelial biomarkers (ET-1 and VCAM-1). Future investigation in this area is needed to assess dysautonomia and vascular tone abnormalities, which may provide potential therapeutic targets for ME/CFS.

Sleep dimensions are associated with obesity, poor diet quality and eating behaviors in school-aged children.

Objectives: The aim of this cross-sectional study was to investigate the association between sleep dimensions (duration, patterns, and disturbances) with body mass index (BMI), diet quality, and eating behaviors in school-aged children. Additionally, we aimed to investigate whether obesogenic eating behaviors (higher food responsiveness, lower satiety responsiveness, and less slowness in eating) and poor diet quality could mediate the potential association between sleep and obesity in school-aged children. Materials and methods: For all participants (n = 588 children, age 5-12 years; 51% girls) we evaluated: sleep dimensions, BMI, diet quality, eating behaviors (food responsiveness, satiety responsiveness and slowness in eating). Linear regression models were used to test associations between exposure and outcome variables. Additionally, path analysis was conducted to test whether eating behaviors mediated the relationship between sleep and obesity. Results: Shorter sleep duration (ß = -0.722, p = 0.009) and greater sleep disturbances (ß = 0.031, p = 0.012) were significantly associated with BMI. Additionally, we observed that diet quality was significantly associated with sleep duration (ß = 0.430, p = 0.004), the midpoint of sleep (ß = -0.927, p < 0.001), and sleep disturbances (ß = -0.029, p < 0.001). Among other findings, greater sleep disturbances were associated with food responsiveness (ß = 0.017, p < 0.001), satiety responsiveness (ß = 0.015, p < 0.001), and slowness in eating (ß = 0.012, p < 0.001). Importantly, food responsiveness was found as significant mediator of the relationship between sleep and BMI (R = 0.427, R 2 = 0.182, p < 0.001). Conclusions: Late sleep patterns, short sleep duration, and greater sleep disturbances are significantly related with what and how school-aged children eat. Importantly, poor diet quality was significantly related to all three sleep dimensions, while eating behaviors had a significant relationship with greater sleep disturbances. These findings may be relevant to the development of behavioral targets to prevent childhood obesity, including sleep hygiene guidelines as a strategy to improve children's eating habits, as well as their BMI.

Adherence to Healthy Lifestyle Habits Is a Determinant of the Effectiveness of Weight Loss among Patients Undergoing Endoscopic Bariatric Therapies.

Endoscopic bariatric therapies (EBTs) are promising strategies for the treatment of obesity. However, there is still great variability in its effectiveness in weight loss. Thus, we investigated whether adherence to healthy lifestyle habits is a significant determinant of weight loss effectiveness among patients undergoing EBTs. Additionally, the role of eating behaviors and psychological traits in the effectiveness of weight loss was studied. A cohort of 361 participants (81.4% women; age 41.8 ± 9.5 years; BMI 37.8 ± 4.3 kg/m2) was followed for 1 year after EBT. Anthropometric parameters, adherence to healthy lifestyle habits, emotional eating, and psychological traits (anxiety and depression) were evaluated. General linear models were used to compare outcome variables according to weight loss effectiveness groups (poor vs. good weight-loss-responders). Additionally, a hierarchical linear regression model was used to determine whether adherence to healthy lifestyle habits, emotional eating, or psychological traits were significant predictors of excess weight loss (%EWL). One year after EBT, weight loss differed significantly between good and poor weight-loss-responders (67.5% EWL [95% CI: 64.2, 70.8] vs. 28.2% EWL [95% CI: 25.5, 30.9], p < 0.001). Participants who adhered to good lifestyle habits had 4.37 more odds [95% CI: 2.19, 8.88] of being good weight-loss-responders. We also observed that eating four to five meals/day and practicing muscle-strengthening activities >2 times/week were the two lifestyle habits that most significantly determined weight loss response. Furthermore, our results revealed that while adherence to healthy lifestyle habits was a significant determinant of %EWL 3, 6, and 12 months after EBT (p < 0.001), emotional eating was a significant determinant of %EWL only 3 and 6 months after the intervention (p < 0.01 and p < 0.05, respectively). Regarding psychological traits, we observed that neither anxiety nor depression were significant determinants of %EWL. Our results revealed that adherence to healthy lifestyle habits is a significant determinant for weight loss effectiveness among patients with obesity undergoing EBT. These findings highlight the importance of implementing an adequate nutritional intervention program, especially since patients who adhere to good lifestyle habits are able to achieve a weight loss that would be comparable with bariatric surgery.

A Mediterranean-Style Diet Plan Is Associated with Greater Effectiveness and Sustainability in Weight Loss in Patients with Obesity after Endoscopic Bariatric Therapy.

This study aimed to investigate the impact of a Mediterranean-style diet on weight loss effectiveness and sustainability in patients with obesity who underwent endoscopic bariatric therapies (EBT), relative to a protein diet plan. Thus, 132 patients with obesity (BMI 30-40 kg/m2) who underwent EBT, were asked to follow a Mediterranean-style diet plan (n = 52) or a protein diet plan (n = 26) for six months. General linear models were used to compare outcome variables between dietary intervention groups. Results showed that participants who followed a Mediterranean-style diet plan lost 14.2% more weight (95% CI: 3.0; 25.3), compared with those who followed a protein diet plan. Additionally, following a Mediterranean-style diet plan was associated with the sustainability of weight loss. Note that three months after the end of the dietary intervention, the patients who followed a Mediterranean-style diet plan were still losing weight (-1.2 ± 3.0 kg), while those with a protein diet plan gained, on average, 2.4 ± 3.3 kg (p < 0.001). Therefore, we conclude that combining EBT with a Mediterranean-style diet plan could represent an effective dietary intervention to improve the effectiveness and sustainability of weight loss after an EBT.

Life before and after COVID-19: The 'New Normal' Benefits the Regularity of Daily Sleep and Eating Routines among College Students.

After the COVID-19 lockdown, a 'new normal' was established, involving a hybrid lifestyle that combined face-to-face with virtual activity. We investigated, in a case-control study, the impact of the 'new normal' on daily sleep and eating routines, compared with pre-pandemic conditions. To do this, we propose using social and eating jet lag as markers of the regularity in daily routines. Additionally, we studied whether the 'new normal' had an impact on the body mass index (BMI), diet quality, and other health-related variables. This study included 71 subjects in the pre-pandemic group, and 68 in the 'new normal' group (20-30 years). For all participants, we evaluated social and eating jet lag, BMI, diet and sleep quality, eating behaviors, physical activity, and well-being. General linear models were used to compare outcome variables between pre-pandemic and 'new normal' groups. The results revealed that the 'new normal' was associated with greater regularity in daily sleep and eating routines (-0.7 h of social jet lag (95% CI: -1.0, -0.4), and -0.3 h of eating jet lag (95% CI: -0.5, -0.1)), longer sleep duration on weekdays (1.8 h (95% CI: 1.5, 2.2)), and lower sleep debt (-1.3 h (95% CI: -1.7, -0.9)). Regarding BMI and other health-related variables, we observed that these variables were similar between 'new normal' and pre-pandemic groups. These findings indicate that the 'new normal' had a positive impact on daily sleep and eating routines. Additionally, our results indicated that the 'new normal' offered college students a more sustainable lifestyle, which was associated with more hours of sleep during the week and lower sleep debt. This, in the long run, could have a positive impact on BMI and overall health.

Emotional eating and cognitive restraint mediate the association between sleep quality and BMI in young adults.

This cross-sectional study was designed to investigate whether diet quality and eating behaviors could mediate the association between sleep quality and body mass index (BMI) in young adults. For all participants (n = 925; aged 21.4 ± 2.5 years; 77.8% women) we evaluated: BMI, sleep quality, diet quality, and eating behavior dimensions (emotional eating, cognitive restraint, and uncontrolled eating). Linear regression models were used to test associations between exposure and outcome variables. Path analysis was conducted with all potential mediators and covariates entered at the same time. Results showed that emotional eating (ß = 0.04 [95% CI: 0.03; 0.06]), cognitive restraint (ß = 0.03 [95% CI: 0.01; 0.04]), uncontrolled eating (ß = 0.02 [95% CI: 0.01; 0.04]) and diet quality (ß = -0.14 [95% CI: 0.19;-0.08]) were significantly associated with sleep quality. Additionally, BMI was significantly associated with PSQI score (ß = 0.09 [95% CI: 0.01; 0.17]), emotional eating (ß = 0.89 [95% CI: 0.60; 1.18]), and cognitive restraint (ß = 1.37 [95% CI: 1.02; 1.71]). After testing for mediation, results revealed that emotional eating and cognitive restraint evidenced a significant mediating effect on the association between sleep quality and BMI. Additionally, diet quality was significantly associated with emotional eating (ß = -0.35 [95% CI: 0.56;-0.13]), cognitive restraint (ß = 0.53 [95% CI: 0.27; 0.79]), and uncontrolled eating (ß = -0.49 [95% CI: 0.74;-0.25]). In conclusion, young adults with poor sleep quality are more likely to deal with negative emotions with food, which, in turn, could be associated with higher cognitive restraint, becoming a vicious cycle that has a negative impact on body weight. Our results also emphasize the role of eating behaviors as determinants of diet quality, highlighting the importance of considering sleep quality and eating behaviors when designing obesity prevention strategies in this population.

A higher dietary restraint is associated with higher BMI: a cross-sectional study in college students.

BACKGROUND: College students tend to have eating and lifestyle habits that can lead to weight gain. Paradoxically, weight gain could also lead to calorie restriction, a practice that is common among those who are concerned about their body weight. Thus, the objective of this study was to investigate the association between habits related to overweight and obesity and dietary intake, physical activity, and BMI among college students. METHODOLOGY: One hundred ninety-two participants (18-26 years; 75% female) were included in this cross-sectional study. Participants completed the 'habits related to overweight and obesity questionnaire' which evaluates five dimensions: the concern about caloric intake, healthy eating, physical activity, alcohol consumption, and eating for psychological well-being. Additionally, anthropometric parameters, dietary intake, and physical activity were evaluated. Linear regression models were used to examine the associations between outcome and exposure variables. RESULTS: Higher concern about caloric intake was associated with higher BMI (1.05 kg/m2 [95%CI: 0.58, 1.51]), but lower energy (-312.2 kcal/day [95%CI: -404.6, -219.8]) and fat intake (-1.88% [95%CI: -2.94, -0.83]). Furthermore, healthy eating was related to better diet quality 0.96 [95%CI: 0.47,1.44] and lower energy intake (-231.4 kcal/day [95%CI: -367.7, -95.2]). Meanwhile, higher scores in the physical activity dimension were associated with better diet quality (0.41 [95%CI: 0.16,0.66]). CONCLUSIONS: College students with the highest dietary restraint had the greatest BMI and the lowest energy and fat intake. Our results highlight the importance of promoting healthy behaviors among college students.

Late bedtime is associated with lower weight loss in patients with severe obesity after sleeve gastrectomy.

BACKGROUND: Previous research has shown that sleep can play a role in obesity and weight loss. However, the association of sleep with weight loss in patients with severe obesity after bariatric surgery remains unexplored. We aimed to evaluate the role of sleep in weight loss evolution in a cohort of patients who underwent sleeve gastrectomy. METHODS: A cohort of 252 patients with severe obesity (75.7% women; age [mean ± SD] 47.7 ± 10.8 years; BMI 44.2 ± 5.9 kg/m2) was followed for 1 year after surgery. Anthropometric, biochemical, physical activity, sleep (bedtime, wakeup time, and sleep duration) and dietary intake variables were collected pre- and post-surgery (1 year). Linear and non-linear regression models were used to examine the associations between sleep variables and weight loss. Participants were grouped into 'early' and 'late' sleepers according to a bedtime threshold (before or after 24:00 h), and the differences in weight loss, physical activity, meal timing, and dietary intake between groups were studied. RESULTS: 1-h increments in bedtime were linearly associated with less excess weight loss (EWL) [-2.23%; 95%CI: -3.37; -0.70; p = 0.005] 1 year after the sleeve gastrectomy. Late sleepers lost less weight (-5.64% of EWL [95%CI: -10.11; -1.17]; p = 0.014) when compared to early sleepers and showed a higher energy intake after 21:00 h (8.66% of total energy intake [95% CI: 4.87; 12.46]; p < 0.001). CONCLUSIONS: Late bedtime is associated with less success of weight loss 1 year after the sleeve gastrectomy. Late sleepers consumed more of their calories closer to bedtime. Our results highlight the relevance of considering recommendations on bedtime and meal timing for patients after bariatric surgery.

Effect of COVID-19 Lockdown on Dietary Habits and Lifestyle of Food Science Students and Professionals from Spain.

On 11 March 2020, the World Health Organization (WHO) declared COVID-19 a global pandemic, forcing countries around the world to confine their population to halt the rapid spread of the virus. This study aimed to evaluate the changes in dietary habits and lifestyle during the COVID-19 lockdown a specific population with academic and professional knowledge in food sciences from Spain. An online questionnaire, based on 41 items, including sociodemographic data, dietary habits, food-related behaviors, and lifestyle were distributed using academic and institutional mailing lists and social media. Results showed a higher intake of fruit and vegetables, legumes, eggs, fish, and yogurt together with a decrease in consumption of alcoholic beverages between before and during the lockdown period. Nevertheless, an increase in consumption of some fruitive foods and an increase in self-reported weight were also observed, although in lower percentages than in other populations. A worse sleep quality and an increase in working hours and sitting time were also reported. Overall, trends towards healthier dietary habits were observed within the study sample during COVID-19 confinement period.

Sleeve gastrectomy in patients with severe obesity restores circadian rhythms and their relationship with sleep pattern.

Advances in research have linked alterations of circadian rhythms with obesity. However, few studies have focused on the recovery of the circadian expression after a weight loss treatment. Our aim was to study the alterations of the circadian rhythmicity due to morbid obesity and the recovery of the circadian pattern after weight loss in a cohort of patients who underwent sleeve gastrectomy. For this purpose, 41 patients with severe obesity (75% women; age [mean (SD)] 49.7 ± 10 years; BMI 44.3 ± 6.2 kg/m2) were monitored before bariatric surgery and 9 months afterward. On both occasions, activity and wrist temperature were determined by actigraphy and were related with weight loss. Anthropometric, biochemical, and sleep-related variables, along with dietary intake and physical activity, were analyzed in relation with circadian rhythmicity. Results show significant differences in the circadian expression before and after 9 months of bariatric surgery, with more stable and less fragmented rhythms after weight loss. Moreover, only after surgery were the circadian variables associated to sleep timing and chronotype. The findings of this study indicate that weight loss treatment in patients with morbid obesity improves the circadian rhythm expression, and in such a way that it could be associated with better sleep quality. Moreover, it allows the recovery of the relationship between sleep patterns and circadian rhythm that was lost due to the obesity.

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.

ADHD subtypes are associated differently with circadian rhythms of motor activity, sleep disturbances, and body mass index in children and adolescents: a case-control study.

To date, few studies have examined the circadian pattern of motor activity in children and adolescents newly diagnosed with attention-deficit/hyperactivity disorder (ADHD). The objective was to study the circadian pattern of motor activity in subjects with ADHD (medication naïve) and to investigate the relationships between alterations in circadian patterns, the ADHD subtype (combined or inattentive), sleep disturbances and body mass index (BMI). One-hundred twenty children and adolescents (60 medication naïve ADHD and 60 controls) were included in a gender- and age-matched case-control study. ADHD was diagnosed according to the DSM-IV-TR, the Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version, and the Conner's Parents Rating Scale-Revised. Circadian rhythms of motor activity and sleep parameters were measured using actigraphy and the Sleep Disturbance Scale for Children. BMI and dietary intake were also evaluated. ADHD patients showed a trend towards eveningness and greater sleep disturbances than controls. Additionally, patients with ADHD-combined had significantly higher mean values of motor activity and showed a significant delay in bedtime. Furthermore, among ADHD-C patients hyperactivity symptoms were significantly associated with the least 5 h of activity. Regarding patients with ADHD-inattentive, increased fragmentation of the circadian pattern was associated with inattention symptoms, and they also showed a significant increase in BMI of 2.52 kg/m2 [95% CI 0.31, 4.73] in comparison with controls. Our findings highlight the potential use of actigraphy as a clinical tool to aid in the diagnosis of ADHD. It should be noted that evaluating motor activity variables could also allow the differentiation between ADHD subtypes.

Adiposity and body mass index of young women are associated with altered 24-hour profile of wrist temperature and sleep quality.

Sleep alterations are linked to circadian disturbances; however, these variables are also related with adiposity, which could impair the study of the previous relationship. Here, we investigated whether the association between adiposity and impaired circadian health is independent of sleep and circadian related variables in a sample of young women. One hundred ninety-two women (18-30 years of age) participated in this cross-sectional study. To evaluate circadian rhythmicity, subjects wore a temperature sensor for six consecutive days, and variables related with the amplitude and stability of the rhythm were calculated. We also assessed adiposity markers (body mass index [BMI], fat mass, waist, and hip circumference), sleep and circadian variables (sleep schedules and quality, social jet lag, and chronotype), energy intake, and physical activity. Partial correlations were conducted to test the associations between circadian and sleep-related variables with adiposity markers. Results showed the circadian pattern of temperature clearly depended on BMI and, to a lesser extent, on sleep variables. Specifically, we showed that higher adiposity was significantly associated with lower amplitude, percentage of variance explained by the rhythm, and intradaily variability and L10 values of the temperature 24 h rhythm. Furthermore, sleep quality was the only variable significantly related with both adiposity and circadian pattern of wrist temperature, while social jet lag and chronotype were only associated with the circadian pattern of temperature. Therefore, we consider BMI should be taken into account when sleep health or disturbances are studied by means of circadian rhythm analyses.

Erratum: Eating Jet Lag: A Marker of the Variability in Meal Timing and its Association with Body Mass Index.

The Nutrients Editorial Office would like to update the error in the original published version[1] [...].

The Elapsed Time between Dinner and the Midpoint of Sleep is Associated with Adiposity in Young Women.

Meal timing relative to sleep/wake schedules is relevant in the search for obesity risk factors. However, clock time does not accurately characterize the timing of food intake in the context of internal circadian timing. Therefore, we studied elapsed between dinner and the midpoint of sleep (TDM) as a practical approach to evaluate meal timing relative to internal timing, and its implications on obesity. To do so, adiposity, sleep, diet, physical activity, and TDM were measured in 133 women. The participants were grouped into four categories according to their sleep timing behavior (early-bed/early-rise; early-bed/late-rise; late-bed/early-rise; late-bed/late-rise). Differences among the categories were tested using ANOVA, while restricted cubic splines were calculated to study the association between TDM and adiposity. Our results show that, although participants had dinner at about the same time, those that had the shortest TDM (early-bed/early-rise group) were found to have significantly higher BMI and waist circumference values (2.3 kg/m2 and 5.2 cm) than the other groups. In addition, a TDM of 6 h was associated with the lowest values of adiposity. The TDM could be a practical approach to personalizing meal timing based on individual sleep/wake schedules. Thus, according to our findings, dining 6 h before the midpoint of sleep is an important finding and could be vital for future nutritional recommendations and for obesity prevention and treatment.

Eating Jet Lag: A Marker of the Variability in Meal Timing and Its Association with Body Mass Index.

The timing of food intake has been associated with obesity and adverse metabolic outcomes, independently of the amount or content of food intake and activity level. However, the impact of the variability in the timing of food intake between weekends and weekdays on BMI (body mass index) remains unexplored. To address that, we propose to study a marker of the variability of meal timing on weekends versus weekdays (denominated as 'eating jet lag') that could be associated with increments in BMI. This cross-sectional study included 1106 subjects (aged 18-25 years). Linear regression models were used to examine the associations of eating jet lag with BMI and circadian related variables (including chronotype, eating duration, sleep duration, and social jet lag). Subsequently, a hierarchical multivariate regression analysis was conducted to determine whether the association of eating jet lag with BMI was independent of potentially confounding variables (e.g., chronotype and social jet lag). Moreover, restricted cubic splines were calculated to study the shape of the association between eating jet lag and BMI. Our results revealed a positive association between eating jet lag and BMI (p = 0.008), which was independent of the chronotype and social jet lag. Further analysis revealed the threshold of eating jet lag was of 3.5 h or more, from which the BMI could significantly increase. These results provided evidence of the suitability of the eating jet lag, as a marker of the variability in meal timing between weekends and weekdays, for the study of the influence of meal timing on obesity. In a long run, the reduction of the variability between meal timing on weekends versus weekdays could be included as part of food timing guidelines for the prevention of obesity among general population.