The authors have declared that no competing interests exist.
Chronic disruption of the synchronous relationship between endogenous and exogenous circadian timing is associated with the development of obesity and metabolic disease. Social jetlag is a measure of circadian misalignment and has been identified as a risk factor for overweight and related diseases. However, the mechanisms involved in this relationship remain underexplored. The objective of this study was to investigate the association between social jetlag and food consumption at late meal timing in patients with obesity-related chronic diseases. This study included 792 individuals (73% female; age 55.9 ± 12.4 years) in which the prevalence of social jetlag (>1h) was 24.4% (n = 194). Participants with social jetlag reported late meal timing for breakfast, early afternoon snack and dinner. Individuals with social jetlag also reported a higher intake of total calories (kcal), protein, total fat, saturated fat, cholesterol, and servings of meat and eggs and sweets in relation to those without social jetlag. Regarding the consumption during each meal of the day, participants with social jetlag had consumed more calories, saturated fat and cholesterol during dinner; more protein, total fat, saturated fat, and cholesterol during lunch; and more total fat and saturated fat during morning snack. In addition, individuals with social jetlag had a higher risk of inadequate consumption of total fat, saturated fat and cholesterol intake when compared with those without social jetlag. We conclude that social jetlag is associated with a poor diet and later meal times, which should be avoided in individuals with obesity-related chronic diseases. More studies are needed to confirm these findings.
The circadian clock system is an endogenous timing system that exists in a multitude of organisms to synchronize physiology and behavior with 24-h environmental cycles and to optimize energy balance, and thus survival [
The need to balance biological preferences with the requirements to meet pre-established working or study schedules can promote disruption of the circadian timing that alters sleep onset and wake up time between weekdays and weekends, producing a condition termed social jetlag [
Despite the scarcity of studies explaining the possible role of social jetlag in the development of overweight and related diseases, studies have suggested that the circadian misalignment measured by social jetlag can compromise the maintenance of a healthy lifestyle, especially the behaviors related to tobacco consumption [
The lack of studies in this area makes evident the need to better explore the influence of social jetlag on feeding behavior, especially the composition of the diet and meal times in different populations, such as individuals with obesity and related diseases. Thus, this study investigated the association between social jetlag and food consumption at late meal timing in patients with obesity-related chronic diseases. We hypothesized that social jetlag is associated with eating meals at later times and eating more calories and fat, as well as an increased amount of food with a high content of these, among individuals with obesity-related chronic diseases.
This cross-sectional study involved volunteers with obesity-related chronic diseases who were attending outpatient clinics of the public health service of Uberlândia city, Minas Gerais State, Brazil. To be eligible to participate in the study, individuals had to have a confirmed medical pre-diagnosis of obesity, type 2 diabetes mellitus (TD2), systemic arterial hypertension or dyslipidemia (hypercholesterolemia, hypertriglyceridemia, or reduced HDL-C). The study was approved by the Ethics Committee of the Federal University of Uberlândia (protocol no. 005464/2015) and all volunteers provided a written informed consent form to participate in the study. Initially, the volunteers answered a questionnaire that assessed demographic aspects and health behaviors related to: sleep pattern, physical activity, alcohol intake, tobacco consumption and use of medicines. The methods used in this study have previously been described in detail elsewhere [
For characterization of sleep pattern, participants were asked to report their usual bedtime, wake-up time, sleep-onset latency and usual sleep duration on weekdays and weekends for the past two weeks. Social jetlag was calculated following the protocol established by Wittman et al. [
The volunteers were asked about physical activity practice, type of exercise, weekly frequency, duration (in minutes of each section) and intensity of exercise. We calculated the total of minutes of physical activity per week by multiplying the frequency per week by the number of minutes per time. Participants were considered physically active if they performed at least 150 minutes of physical exercise per week [
Anthropometric measures were obtained by an expert team. Weight was determined by a scale to an accuracy of 0.1Kg (Welmy, São Paulo, Brazil) and height was measured using a stadiometer fixed to the wall with an accuracy of 0.1cm (Toledo Scale Corp., Toledo, Ohio). Height and weight were used to calculate the body mass index (BMI, kg/m2); a value above 25 kg/m2 or 30 kg/m2 was considered as overweight or obesity, respectively [
The volunteers reported their food intake with the help of a team of three highly trained and experienced nutritionists in studies investigating food consumption. Dietary intake was assessed by a single 24-hour food recall (24h-FR) using the multiple pass method developed by the US Department of Agriculture (USDA) [
For daily intake we calculated: eating duration, defined as the time interval which reflects the length between the first and last caloric event each day [
For the definition of each meal (breakfast, lunch, snacks, dinner or supper), we asked the participants about their perceptions and we also analyzed the type of food often present in the Brazilian diet. The pattern of a typical Brazilian diet includes three main meals: breakfast, lunch and dinner. Intermediate snacks are also frequent and tend to be eaten in the middle of the morning or afternoon [
The foods reported by the participants were converted into servings according to the energy content and were categorized into eight food groups: cereals, bread and pasta (150 calories); vegetables (15 calories); fruit (70 calories); beans (55 calories); meat and eggs (190 calories); milk and dairy products (120 calories); oils and fats (73 calories); and sweets (110 calories); following the established by the Adapted Food Pyramid [
All statistical analyses were performed with SPSS version 20.0 (SPSS Inc., Chicago, IL, USA), and p<0.05 was considered to be statistically significant. Initially, the volunteers were divided into two groups: patients with social jetlag (>1h) and without social jetlag (≤1h) [
In order to determine confounding factors, Pearson or Spearman’s correlation was carried out between the dependent variables and possible confounding variables (age, sex, family income, employment status, minutes of physical activity per week, BMI, mean sleeping duration, time of diagnosis of the chronic disease and use of insulin, antidepressants and/or sleeping pills). The variables correlated with each dependent variable in the Pearson or Spearman’s correlation (r> 0.20) were subjected to GzLM or multivariate logistic regression.
Multivariate logistic regression was used to predict the risk of ingestion above the recommendations of macronutrients, cholesterol, fiber and each food group by comparing the group with social jetlag (>1h) with those without social jetlag (≤1h). These results were expressed as the odds ratio with 95% confidence interval (CI).
This study included 792 individuals (73% female; age 55.9 ± 12.4 years) (
All |
Social jetlag ≤ 1h |
Social jetlag > 1h |
p |
|
---|---|---|---|---|
Age (years) | 55.9 ± 12.4 | 57.9 ± 11.6 | 49.8 ± 12.7 | |
Female (%) | 581 (73.0) | 433 (72.5) | 148 (76.2) | 0.30 |
Marital status–Married (%) | 401 (51.0) | 304 (51.0) | 97 (50.0) | 0.27 |
Family income–(U$ 553.0) | 504 (63.0) | 378 (63.2) | 126 (65.0) | 0.36 |
Education–< = 12 years | 514 (69.0) | 401 (67.0) | 113 (58.2) | |
Day workers (%) | 281 (35.9) | 192 (32.5) | 89 (46.3) | |
Retired (%) | 308 (39.3) | 261 (44.2) | 47 (24.4) | |
Hours per week | 40.8 ± 8.9 | 40.7± 9.3 | 41.0±8.1 | 0.80 |
Smoking status–Yes (%) | 96 (12.0) | 66 (11.0) | 30 (15.4) | 0.10 |
Alcohol intake–Yes (%) | 220 (28.0) | 155 (26.0) | 65 (33.5) | 0.10 |
Alcohol–Servings/week | 2.0 [0.75–6.0] | 2.0 [0.5–5.25] | 4.0 [1.4–8.0] | |
Physical activity (PA)–Yes (%) | 294 (37.0) | 235 (39.3) | 59 (30.4) | |
Minutes of PA/week |
180 [120–300] | 180 [120–300] | 180 [100–300] | 0.34 |
BMI (kg/m2) | 30.0 ± 6.3 | 29.4±6.4 | 30.1±5.6 | 0.13 |
Overweight (%) | 575 (72.6) | 421 (70.4) | 154 (79.4) | |
Obese (%) | 423 (53.4) | 319 (53.3) | 104 (53.6) | 0.94 |
Abdominal obesity (%) |
564 (71.0) | 423 (70.6) | 141 (72.6) | 0.58 |
High neck circumference (%) |
518 (65.0) | 395 (66.2) | 123 (63.4) | 0.46 |
Bedtime weekday (h:min) |
22:12 [21:12–23:12] | 22:25 [21:50–23:25] | 22:00 [20:55–22:55] | |
Bedtime weekend (h:min) |
22:30 [21:30–24:00] | 22:30 [21:30–23:30] | 23:40 [22:30–24:50] | |
Waketime weekday (h:min) |
06:00 [05:30–07:00] | 06:00 [06:00–07:00] | 06:00 [05:30–07:00] | 0.339 |
Waketime weekend (h:min |
07:00 [06:00–08:30] | 06:50 [06:00–08:00] | 09:00 [08:00–10:00] | |
Sleep duration weekday (h:min) | 07:30 [06:30–09:00] | 07:00 [06:00–08:25] | 07:00 [06:00–08:25] | 0.998 |
Sleep duration weekend (h:min) | 08:00 [07:00–09:00] | 07:42 [06:00–08:40] | 08:25 [06:55–09:30] | |
Mean sleeping duration (h) | 07:30 ± 01:30 | 07.20 ± 01:40 | 07:30. ± 02:00 |
Note: Values are presented as mean and standard deviation for normally distributed data or as median (interquartile range) for non-normally distributed data.
*Pearson’s chi-square test was used to compare proportion variables and Student’s t-tests or Mann–Whitney test for independent samples were used in the comparisons for continuous variables. Bold value is statistically significant at
↑Time is presented in 24-h clock time.is presented in 24-h clock time.
ΩWaist circumference≥102cm for men and≥88cm for women were considered abdominal obesity.
ΦNeck circumference ≥39cm for men and ≥35cm for women were considered high.
ΧOnly those reported to perform physical activities.
We found a good representation of the days of the week and the weekend of 24-hour food recall collected in the present study: Monday = 21.0%, Tuesday = 27.7%, Wednesday = 23.5%, Thursday = 7.0%, Friday = 3.0% and Sunday = 17.8%.In this sense, we identified that 82.2% were evaluated on weekdays and 17.8% on weekends. No statistical difference was identified in the proportion of 24-hour recalls for weekdays and weekends among individuals with or without social jetlag(p = 0.87).
All (n = 792) | Social Jetlag ≤ 1h (n = 598) | Social Jetlag > 1h (n = 194) | |
---|---|---|---|
Means ± SE | Means ± SE | p |
|
Calories (kcal/day) | 1508.3 ± 20.2 | 1621.6 ± 38.1 | |
Carbohydrate (g/day) | 182.0 ± 2.7 | 186.6 ± 5.0 | 0.42 |
Protein (g/day) | 76.5 ± 1.4 | 85.1 ± 2.7 | |
Total fat (g/day) | 52.6 ± 1.0 | 59.9 ± 2.1 | |
Saturated Fat (g/day) | 17.3 ± 0.4 | 19.4 ± 0.8 | |
Cholesterol (mg/day) | 246.2 ± 6.3 | 315.9 ± 14.1 | |
Fiber (g/day) | 13.6 ± 0.2 | 13.3 ± 0.4 | 0.50 |
Cereals, breads and pasta | 3.8 ± 0.07 | 3.9 ± 0.13 | 0.47 |
Vegetables | 1.9 ± 0.06 | 2.0 ± 0.12 | 0.94 |
Fruits | 3.2 ± 0.13 | 3.17 ± 0.24 | 0.95 |
Beans | 1.7 ± 0.04 | 1.8 ± 0.09 | 0.38 |
Meat and eggs | 2.2 ± 0.05 | 2.5± 0.10 | |
Dairy | 1.6 ± 0.05 | 1.6 ± 0.09 | 0.68 |
Oils and fat | 2.2 ± 0.08 | 2.2 ± 2.14 | 0.89 |
Sweets | 1.4 ± 0.06 | 1.7 ± 0.12 | |
Breakfast (h:min) | 7:20 ± 0:02 | 7:44 ± 0:04 | |
Morning snack (h:min) | 9:47 ± 0:04 | 9:45 ± 0:06 | 0.84 |
Lunch (h:min) | 12:06 ± 0:18 | 12:12 ± 0:03 | 0.37 |
Early afternoon snack (h:min) | 15:36 ± 0:02 | 15:54 ± 0:05 | |
Late afternoon snack (h:min) | 17:22 ± 0:11 | 17:04 ± 0:18 | 0.45 |
Dinner (h:min) | 19:42 ± 0:06 | 20:12 ± 0:11 | |
Supper (h:min) | 20:31: 0:25 | 20:51 ± 0:05 | 0.76 |
Eating duration |
12:45 ± 0:06 | 13:09 ± 0:10 | |
Caloric midpoint |
13:41 ± 0:05 | 14:02 ± 0:10 | 0.08 |
Calories after 9 p.m. |
105,1 ± 10.2 | 188,4 ± 26.9 | |
Calories after 9 p.m. |
6.2 ± 0.5 | 10.5 ± 0.9 | |
Number of eating episodes | 4.2± 0.4 | 4.1± 0.4 | 0.21 |
*GzLM analyses were adjusted for age, sex, BMI, minutes of physical activity per week and mean sleeping duration. Bold value is statistically significant at
¥Total individuals who reported performing each of the meals or snacks: breakfast (n = 747); morning snack (n = 237); lunch (n = 779); early afternoon snack (n = 604); late afternoon snack (n = 64); dinner (n = 733); and supper (n = 128).
∞Length between the first and last caloric event each day.
∑Caloric midpoint: the average time at which 50% of daily calories had been consumed.
EI: energy intake.
When we analyzed the distribution of calories and macronutrients between meals, the group with social jetlag had a higher calorie (kcal) intake at dinner (p = 0.03), protein intake (g)at lunch (p = 0.01), total fat (g) intake in the morning snack (p = 0.02) and lunch (p = 0.03),higher saturated fat (g) intake in the morning snack (p = 0.02), lunch (p = 0.03) and dinner (p = 0.03);and higher cholesterol (mg) intake at lunch (p<0.001) and dinner (p<0.001) -when compared to those without social jetlag (
Note: A. Calories (kcal): group with social jetlag had a higher calorie (kcal) intake at dinner (443.4 ± 10.5 vs. 488.4 ± 19.8; p = 0.03). B. Carbohydrate (g): no association of social jetlag. C. Protein (g): group with social jetlag had a higher protein (g) intake at lunch (36.2 ± 0.80 vs 40.5 ± 1.60; p = 0.01). D. Total fat (g): group with social jetlag had a higher total fat intake (g) in the morning snack (p = 0.02) and lunch (p = 0.03). E. Saturated fat (g): group with social jetlag had a higher saturated (g) fat intake in the morning snack (1,0g ± 0.13 vs. 2.1g ± 0.59; p = 0.02); lunch (5.3g ± 0.18 vs. 6.2g ± 0.37;p = 0.03) and dinner (5.1g ± 0.19 vs. 5.9g ± 0.38; p = 0.03). F. Cholesterol (mg) group with social jetlag had a higher cholesterol intake (mg) at lunch (120.4 ± 3.1 vs. 146.5 ± 6.6 p<0.001) and dinner (106.5 ± 3.7 vs. 135.3 ± 8.0; p<0.001). *GzLM analyses were adjusted for age, sex, BMI, minutes of physical activity per week and mean sleeping duration. Values are presented as mean and standard error (SE).Total individuals who reported performing each of the meals or snacks: breakfast (n = 747); morning snack (n = 237); lunch (n = 779); early afternoon snack (n = 604); late afternoon snack (n = 64); dinner (n = 733); and supper (n = 128). Caloric intake reported after 9 p.m. was related to the food consumption of the dinner and / or supper, depending on the consumption schedules of the individuals. B: breakfast; MS: morning snack; L: lunch; ES: early afternoon snack; LS: late afternoon snack; D:dinner; S:super.
The results of the adjusted logistic regression indicated a higher risk of consumption above recommendations for total fat (odds ratio [OR] = 1.3, CI = 1.1–1.9; p = 0.03], saturated fat (OR = 1.2, CI = 1.1–2.0; p = 0.01) and cholesterol intake (OR = 1.8, CI = 1.3–2.6; p<0.001) in individuals with social jetlag when compared to those without social jetlag (
Food intake | Inadequate food consumption |
OR (IC 95%) |
p |
---|---|---|---|
Cereals, bread and pasta | <5 or >9 servings/day | 1.0 (0.5–1.1) | 0.23 |
Vegetables | <4 servings/day | 1.2 (0.6–2.3) | 0.60 |
Fruits | <3 servings/day | 1.0 (0.7–1.6) | 0.80 |
Beans | <1 servings/day | 1.2 (0.8–1.7) | 0.23 |
Meat and eggs | <1 or >2 servings/day | 1.0 (0.7–1.4) | 0.81 |
Milk and dairy | <3 servings/day | 0.7 (0.4–1.4) | 0.35 |
Oils and fats | >2 servings/day | 1.2 (0.8–1.7) | 0.22 |
Sweets | >1 servings/day | 1.0 (0.6–1.5) | 0.94 |
Carbohydrate (%EI) | <45 or >65% (EI) | 1.1 (0.8–1.6) | 0.46 |
Protein (%EI) | <10 or >35% (EI) | 1.4 (0.5–4.2) | 0.46 |
Total fat (%EI) | >30% (EI) | 1.3 (1.1–1.9) | |
Saturated fat (%EI) | >10% (EI) | 1.2 (1.1–2.0) | |
Cholesterol (mg/day) | >300 mg/day | 1.8 (1.3–2.6) | |
Fiber (g/day) | <14g/1000 calories/day | 1.7 (0.9–3.3) | 0.09 |
*Multivariate logistic regressions analysis adjusted model for age, sex, BMI, minutes of physical activity per week and mean of sleep duration. Bold value is statistically significant at
This study evaluated the association between social jetlag and food consumption at late meal timing in patients with obesity-related chronic diseases. The participants with social jetlag (>1h) had a higher intake of calories, protein, total fat, saturated fat, cholesterol, and servings of meat, eggs, and sweets in relation to those without social jetlag (< = 1h). They also reported a longer eating duration and later meal timing for breakfast, early afternoon snack and dinner. Regarding the composition of each meal, individuals with social jetlag ate more calories, saturated fat and cholesterol during dinner; protein, total fat, saturated fat, and cholesterol during lunch; and total fat and saturated fat during the morning snack. In addition, individuals with social jetlag had a higher risk of inadequate consumption of total fat, saturated fat and cholesterol intake when compared with those without social jetlag (≤1h). These results suggest that social jetlag is associated with a poor diet and later meal times, which should be avoided in individuals with obesity-related chronic diseases. More studies are needed to confirm these results and to describe the possible mechanisms that explain these associations.
Until now, few studies have evaluated the effects of social jetlag on food intake. A study on rats showed that the combination of social jetlag and a cafeteria diet (rich in fat and carbohydrates) led the animals to overeat and also increased their bodyweight and the number of criteria indicating metabolic syndrome [
The widespread availability of electrical lighting and the current habit of using media such as the television, computer or mobile phone especially prior to bedtime [
In the present study, participants with social jetlag ate their breakfast, early afternoon snack and dinner at a later time than those without social jetlag (
Eating at a later time could alsoinfluence the success of weight-loss therapy [
The data on the composition of each meal revealed that individuals with social jetlag consumed calories, saturated fat and cholesterol at dinner; more protein, total fat, saturated fat, and cholesterol at lunch; and more total fat and saturated fat during their morning snack (
This study has some limitations. First, its cross-sectional design does not allow the establishment of causal relationships, although it could be considered sufficient to address the main objective of the study. Some evaluations were carried out using questionnaires, which, although validated in other studies, are subjective in nature and depend on an individual’s memory and motivation. For this reason we used an expert team of researchers with experience in studies with similar methodology. Also, the analysis of the food intake only by one day of food recall may possibly compromise the accuracy of data on calories, macronutrients [
In summary, we conclude that social jetlag is associated with the schedules of meals and snacks, dragging consumption to later periods of the day. In addition, the presence of social jetlag is related to the total consumption and distribution of calories and macronutrients, especially proteins, total fats, saturated fat and cholesterol, throughout the day. This evidence compliments that found in experimental studies and laboratory conditions, which has revealed a negative impact of circadian misalignment on food behavior. It is necessary to carry out new studies to verify whether the synchronization of feeding behavior, as well as of sleeping and waking hours, with environmental cycles could minimize the impacts of these factors on health, especially in individuals in which obesity-related chronic diseases are already present.
(XLS)
We would like to thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the doctoral grants to MCM.