Podcast
Questions and Answers
Which of the following best describes the primary focus of the study?
Which of the following best describes the primary focus of the study?
- The impact of exercise on sleep quality and duration.
- The correlation between sleep duration and metabolic health.
- The effects of different macronutrient ratios on weight gain.
- The relationship between the timing of food consumption relative to circadian rhythms and body composition. (correct)
Why might using only clock hour to document eating times be misleading, according to the study?
Why might using only clock hour to document eating times be misleading, according to the study?
- Clock hour does not account for individual differences in activity levels.
- Clock hour does not reflect the influence of social jetlag.
- Clock hour fails to consider the impact of macronutrient composition.
- Clock hour does not account for individual differences in circadian timing. (correct)
What method was used to determine the endogenous circadian time of the participants?
What method was used to determine the endogenous circadian time of the participants?
- Questionnaires about sleep and wakefulness patterns.
- Time-stamped-picture mobile phone application for food intake.
- Assessment of melatonin release in a laboratory setting. (correct)
- Actigraphy monitoring for sleep patterns.
What was the main finding regarding the relationship between body fat and food intake timing?
What was the main finding regarding the relationship between body fat and food intake timing?
Which factor was NOT found to have a significant relationship with body composition measures in this study?
Which factor was NOT found to have a significant relationship with body composition measures in this study?
According to the study, what is the potential implication of consuming food during the circadian evening and/or night?
According to the study, what is the potential implication of consuming food during the circadian evening and/or night?
Which biological process is described as being necessary for healthy physiologic functioning?
Which biological process is described as being necessary for healthy physiologic functioning?
What can result from altering the timing of wakefulness, according to the article?
What can result from altering the timing of wakefulness, according to the article?
In mammals, how is the internal circadian timing system entrained?
In mammals, how is the internal circadian timing system entrained?
What health outcomes are associated with misalignment between behavior and endogenous circadian physiology?
What health outcomes are associated with misalignment between behavior and endogenous circadian physiology?
According to the study, what populations may be more prone to pushing activities to a later clock hour?
According to the study, what populations may be more prone to pushing activities to a later clock hour?
What was the age range of the participants enrolled in the cross-sectional study?
What was the age range of the participants enrolled in the cross-sectional study?
During the study, what tool was used to record all food intake across 7 consecutive days?
During the study, what tool was used to record all food intake across 7 consecutive days?
Which of the following describes one of the exclusion criteria for participation in the study?
Which of the following describes one of the exclusion criteria for participation in the study?
Which instrument was used to monitor sleep and wakefulness patterns in this study?
Which instrument was used to monitor sleep and wakefulness patterns in this study?
What instructions were participants given regarding meals that were consumed within 15 minutes of each other?
What instructions were participants given regarding meals that were consumed within 15 minutes of each other?
What was the purpose of the participants’ overnight stay at the Brigham and Women’s Hospital Center for Clinical Investigation Intensive Physiologic Monitoring Unit?
What was the purpose of the participants’ overnight stay at the Brigham and Women’s Hospital Center for Clinical Investigation Intensive Physiologic Monitoring Unit?
What was the threshold level used to calculate dim-light melatonin onset (DLMO) in this study?
What was the threshold level used to calculate dim-light melatonin onset (DLMO) in this study?
What tool was employed to assess body composition in the study?
What tool was employed to assess body composition in the study?
Why were meals coded in duplicate (i.e., scored by 2 nutritionists)?
Why were meals coded in duplicate (i.e., scored by 2 nutritionists)?
From the choices below, identify the baseline requirement that deemed participants adequate for analysis?
From the choices below, identify the baseline requirement that deemed participants adequate for analysis?
How did the study determine the activity level for each participant?
How did the study determine the activity level for each participant?
What term is used to describe the misalignment between sleep and wakefulness timing on free days compared with work and school days?
What term is used to describe the misalignment between sleep and wakefulness timing on free days compared with work and school days?
According to the document, what percentage of participants consistently documented caloric intake events for 7 days?
According to the document, what percentage of participants consistently documented caloric intake events for 7 days?
In the study, how were participants divided into lean and nonlean groups?
In the study, how were participants divided into lean and nonlean groups?
What did the results indicate about the clock times at which men and women reached their caloric midpoint?
What did the results indicate about the clock times at which men and women reached their caloric midpoint?
What variable was significantly associated with the percentage of body fat when controlling for sex?
What variable was significantly associated with the percentage of body fat when controlling for sex?
What does the study suggest regarding the relationship between the timing of the latest daily food intake relative to DLMO and sleep duration?
What does the study suggest regarding the relationship between the timing of the latest daily food intake relative to DLMO and sleep duration?
What did individuals who consumed a greater percentage of their daily calories between 4 hours before DLMO and sleep onset demonstrate?
What did individuals who consumed a greater percentage of their daily calories between 4 hours before DLMO and sleep onset demonstrate?
According to the study, what is a potential mechanism for increased body fat in response to later meal timing?
According to the study, what is a potential mechanism for increased body fat in response to later meal timing?
What did previous studies show about participants in controlled laboratory settings with restricted sleep and provided food ad libitum?
What did previous studies show about participants in controlled laboratory settings with restricted sleep and provided food ad libitum?
What did the study suggest regarding the relationship between eating duration and percentage of calories consumed 4 hours before DLMO until sleep onset?
What did the study suggest regarding the relationship between eating duration and percentage of calories consumed 4 hours before DLMO until sleep onset?
What is emphasized as important in addition to the traditional risk factors of diet and exercise?
What is emphasized as important in addition to the traditional risk factors of diet and exercise?
According to the study, which of the populations listed are known to have late eating habits?
According to the study, which of the populations listed are known to have late eating habits?
What is suggested as a more direct correlate with circadian timing than clock time?
What is suggested as a more direct correlate with circadian timing than clock time?
What recommendation is made before translation of this work to clinical settings?
What recommendation is made before translation of this work to clinical settings?
Consuming food further away from melatonin onset is associated with a lower percentage of body fat.
Consuming food further away from melatonin onset is associated with a lower percentage of body fat.
The study used a food frequency questionnaire to assess dietary intake.
The study used a food frequency questionnaire to assess dietary intake.
According to the research, variations in Macronutrient composition have a greater impact on body composition compared to the timing of caloric consumption relative to melatonin onset.
According to the research, variations in Macronutrient composition have a greater impact on body composition compared to the timing of caloric consumption relative to melatonin onset.
The study confirmed that individuals with a later clock hour for food intake, irrespective of their circadian rhythm, tend to have higher body fat percentages.
The study confirmed that individuals with a later clock hour for food intake, irrespective of their circadian rhythm, tend to have higher body fat percentages.
Light-emitting eReaders, when used in the evening, enhance sleep quality by promoting earlier melatonin onset
Light-emitting eReaders, when used in the evening, enhance sleep quality by promoting earlier melatonin onset
Non-lean individuals (high body fat) consumed most of their calories approximately 1.1 hours closer to melatonin onset than lean individuals.
Non-lean individuals (high body fat) consumed most of their calories approximately 1.1 hours closer to melatonin onset than lean individuals.
The thermic effect of food (TEF) is consistent throughout the day; therefore, meal timing has no impact on TEF.
The thermic effect of food (TEF) is consistent throughout the day; therefore, meal timing has no impact on TEF.
The study design involved a longitudinal study where participants were monitored over several years to track changes in body composition.
The study design involved a longitudinal study where participants were monitored over several years to track changes in body composition.
Individuals with a shorter eating duration (the time between the first and last caloric event of the day) tend to consume a greater percentage of their calories during their biological night.
Individuals with a shorter eating duration (the time between the first and last caloric event of the day) tend to consume a greater percentage of their calories during their biological night.
The study found no significant difference in the food timing between weekdays and weekends.
The study found no significant difference in the food timing between weekdays and weekends.
Flashcards
Later eating and metabolic health
Later eating and metabolic health
Eating at a later clock hour is a newly described risk factor for adverse metabolic health.
Food consumption study
Food consumption study
The timing of food consumption relative to clock hour and endogenous circadian time, content of food intake, and body composition.
Body fat and meal timing
Body fat and meal timing
Nonlean individuals consumed most of their calories 1.1 h closer to melatonin onset than did lean individuals.
Evening food intake
Evening food intake
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Importance of timing
Importance of timing
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Light-dark entrainment
Light-dark entrainment
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Circadian eating Risks
Circadian eating Risks
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Clock hour limitations
Clock hour limitations
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Dim-light melatonin onset (DLMO)
Dim-light melatonin onset (DLMO)
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Thermic effect of food (TEF)
Thermic effect of food (TEF)
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Calories near sleep
Calories near sleep
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DLMO proximity
DLMO proximity
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College students and obesity
College students and obesity
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Circadian timing vulnerability
Circadian timing vulnerability
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Melatonin and body fat
Melatonin and body fat
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Melatonin Calculation
Melatonin Calculation
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Study Notes
Overview
- A study investigated the link between the timing of food intake and body fat in 110 participants aged 18-22 years.
- The cross-sectional study was 30 days long
- It examined eating times relative to both clock hour and individual circadian rhythms, food content, and body composition.
- Eating at a later clock hour poses risks for adverse metabolic health
Key Findings
- Individuals with higher body fat (nonlean) consumed most calories 1.1 hours closer to melatonin onset, signaling the biological night, compared to leaner individuals.
- Measured using log-rank P = 0.009
- There was no difference in the clock hour of food consumption between lean and nonlean individuals.
- Clock hour of food consumption measured at P = 0.72
- Food intake timing relative to melatonin onset significantly correlated with body fat percentage and BMI
- Had significantly lower P values < 0.05
- Clock hour of food intake, caloric amount, macronutrient composition, activity level, or sleep duration had no correlation.
- All values were above P > 0.72
Implications
- Consuming food during the circadian evening or night, regardless of traditional risk factors, significantly impacts body composition.
- Human circadian rhythms are designed to promote behaviors/activities during the day and the night
- Recent availability of electrical lighting allows humans to extend wakefulness into the night, affecting circadian physiology which can lead to a number of adverse health outcomes
- Populations susceptible to pushing activities to a later clock hour include rotating shift workers, adolescents, and college-aged individuals
- Registered at clinicaltrials.gov as NCT02846077
- Researchers documented the timing and content of dietary intake using a mobile phone application over a week.
- Participants recorded all food and beverages consumed, except water, using the MealLogger app, capturing time-stamped photos and detailed descriptions.
Methodology and Analysis
- Exclusion criteria included inability to wear actigraphy monitors or travel across time zones.
- No participants reported night work during the protocol
- Participants used wrist actigraphy monitors and electronic sleep-wake diaries to monitor sleep patterns.
- Dietary intake was assessed over 7 days using the MealLogger app.
- Monitoring period for meal timing began >1 week after the start of the protocol
- This was to ensure participants were familiar with the study procedures
- Caloric events (food or beverage except water) were recorded, with a mean of 3.1 events per day.
- Ranged from 1.5 to 9.3 caloric events per day
- Lean and nonlean groups were defined based on sex-dependent body fat percentage criteria.
- Activity levels were categorized, and social jetlag was calculated.
- Statistical analyses included t-tests, Kaplan-Meier survival curves, and multiple linear regressions
Additional Observations
- The study supports that there is eating later on weekends compared to weekdays
- The lean and nonlean groups had similar DLMO timings.
- 2325 ± 0148 (1752–0338) and 2303 ± 0130 (1946–0135), respectively (P = 0.29).
- The location of the caloric midpoint was a better predictor for body fat than clock time.
- Individuals who consumed a higher percentage of daily calories between 4 hours before DLMO and sleep onset had higher body fat.
- Late daily food intake relative to DLMO correlated with less sleep.
Potential Mechanisms
- A decreased thermic effect of food (TEF) due to later meal timing may contribute to increased body fat.
- Short sleep duration may increase food consumption and shift dietary intake closer to DLMO.
Limitations and Future Directions
- The researchers acknowledge the need to account for underreporting of calories
- They implemented many procedures to avoid this issue during the protocol
- Further research is needed to assess direct measurements of energy expenditure
- Future studies should include altering the timing of meals relative to melatonin.
- The team recommends testing non-college-aged populations to extend the current findings
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