Light Exposure + Meal Timing for Circadian Rhythm Management

(LipidPRC Trial)

Overseen By Leilah K Grant, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: Brigham and Women's Hospital

Must not be taking: Sleep aids, Stimulants

Disqualifiers: Sleep disorders, Psychiatric disorder, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: 6.5 hours per session

48 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how light exposure and meal timing can reset the body's internal clock, or circadian rhythm. Participants will either receive bright light exposure, follow a time-restricted eating schedule (a 12-hour meal window), or maintain a normal eating schedule in dim light. The study aims to determine which factor more effectively manages sleep patterns and metabolism. This trial suits healthy individuals aged 18-30 who do not smoke and can adhere to an 8-hour sleep schedule without sleep aids. As an unphased trial, it offers a unique opportunity to contribute to groundbreaking research on circadian rhythms and overall health.

Do I have to stop taking my current medications for the trial?

Yes, you will need to refrain from taking medications and supplements during the study, except for birth control.

What prior data suggests that these methods are safe for managing circadian rhythms?

Research has shown that bright light therapy is generally safe and well-tolerated. Studies have found that it helps manage sleep problems by adjusting the body's internal clock. Bright light therapy is used in clinical settings and is easy to use, with low costs and few side effects.

Evidence suggests that time-restricted eating positively affects health by improving appetite control and sleep patterns. This method limits the hours during which one eats each day and may help regulate the body's natural rhythms. Participants usually adapt well without significant negative effects.

Both treatments have promising safety records based on existing research. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores how light exposure and meal timing can be used to manage circadian rhythms, potentially offering a non-drug approach to improve sleep and overall health. Unlike standard treatments that might involve medications or supplements, this trial investigates how a 12-hour meal window and bright or dim light exposure can naturally regulate our body's internal clock. The bright light treatment provides a specific 6.5-hour light pulse, which might help reset the circadian rhythm more effectively than current options. Meanwhile, time-restricted eating focuses on the timing of meals, which could have unique metabolic benefits. This trial could pave the way for lifestyle-based interventions that are more accessible and have fewer side effects than pharmaceutical options.

What evidence suggests that this trial's treatments could be effective for circadian rhythm management?

This trial will compare the effects of bright light therapy and time-restricted eating on circadian rhythm management. Research shows that bright light therapy, which participants in this trial may receive, can improve sleep and the body's internal clock, known as circadian rhythms. Studies have found that it can increase total sleep time and enhance sleep efficiency. It also helps stabilize the body's daily rhythm and is used to manage sleep disorders like delayed sleep phase syndrome.

Time-restricted eating, another treatment option in this trial, involves eating only during certain hours and may improve health by aligning meal times with the body's natural clock. It might aid in weight loss and enhance how the body processes food. Some studies suggest it could also help with blood sugar control and lower health risks. Both treatments show potential in managing circadian rhythms, but more research is needed to fully understand their effectiveness. ^{1 2 6 7 8}

Are You a Good Fit for This Trial?

This trial is for healthy individuals aged 18-30 who don't smoke, use drugs, or have sleep disorders. They must maintain an 8-hour sleep schedule and avoid caffeine, alcohol, and most medications during the study. Participants should have a BMI between >18 and <30 kg/m2.

Inclusion Criteria

Body Mass Index of >18 or <30 kg/m2

Non-smoking for at least 6 months

I can avoid caffeine, alcohol, medication, and supplements during the study.

Exclusion Criteria

Any other reason as determine by the Principal Investigator

Transmeridian travel (2 or more time zones) in the past 3 months

I have a recent or ongoing health issue.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo interventions involving 6.5-hour bright light exposure and time-restricted eating to study circadian rhythm shifts

6.5 hours per session

Daily sessions

Follow-up

Participants are monitored for changes in melatonin and lipid levels after interventions

24 hours

What Are the Treatments Tested in This Trial?

Interventions

• 12-h meal window
• Bright Light
• Dim light
• Time-restricted eating

Trial Overview The study tests whether light exposure or meal timing has a greater effect on resetting circadian rhythms related to melatonin production and metabolism. It involves time-restricted eating within a 12-hour window and exposure to bright or dim light.

How Is the Trial Designed?

Group I: Time-restricted eating Experimental Treatment 2 Interventions

Participants will consume 4 identical meals, as in the other groups, except that the meal window will be restricted to 6.5 hours instead of 12 hours (meals at 4.75, 6.9, 9.1, 11.25 hours after waking) centered within the 16-hour wake episode. Participants will remain in dim light (\<3 lux) throughout the 16-hour wake episode.

Group II: Bright light Experimental Treatment 2 Interventions

Participants will receive a 6.5-hour 10,000 lux light pulse (4100K fluorescent light) centered within the 16-hour wake episode (start 4.75 hour after wake and end 11.25 hour after wake). Participants will receive 4 identical meals (equal calories and macronutrient content), over a 12-hour interval (meals at 2, 6, 10, and 14 hours after waking) centered within the 16-hour wake episode.

Group III: Control Placebo Group 2 Interventions

Participants will receive 4 identical meals (equal calories and macronutrient content), over a 12-hour interval (meals at 2, 6, 10, and 14 hours after waking) centered within the 16-hour wake episode. Participants will remain in dim light (\<3 lux) throughout the 16-hour wake episode.

Who Is Running the Clinical Trial?

Brigham and Women's Hospital

Lead Sponsor

Trials

1,694

Recruited

14,790,000+

Published Research Related to This Trial

Timed calorie restriction can significantly influence the body's master circadian clock in the suprachiasmatic nuclei, enhancing the effects of light on this clock even in a light-dark cycle.

Meal timing affects secondary circadian clocks in the brain differently, with some areas being highly responsive to food cues, leading to food-anticipatory activity before meals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Metabolic and reward feeding synchronises the rhythmic brain. Challet, E., Mendoza, J.[2014]

In an 8-week pilot study with 8 participants, consuming a larger portion of daily calories in the morning led to significantly greater weight loss and improved regularity of sleep patterns compared to eating more calories in the evening.

This research suggests that timing of energy intake may enhance biological circadian rhythms, but further studies with larger groups and more comprehensive methods are needed to fully understand its health impacts.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Daily pattern of energy distribution and weight loss. Raynor, HA., Li, F., Cardoso, C.[2019]

Time-restricted eating (TRE) has shown promising therapeutic effects in rodent studies, particularly in relation to body weight and metabolic health, but results in humans are inconsistent due to varying study designs and populations.

This review highlights the need for more standardized research on TRE in humans to better understand its effects and interactions with circadian biology, as well as to identify gaps in current knowledge for future studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Complex physiology and clinical implications of time-restricted eating. Petersen, MC., Gallop, MR., Flores Ramos, S., et al.[2023]

Time-restricted eating (TRE), which limits food intake to 6 to 10 hours during the active part of the day, has been shown to improve metabolic health and glucose tolerance in various models, including humans.

Most research on TRE has focused on starting the eating window in the morning, but this paper highlights potential challenges and metabolic effects of delaying the eating window, suggesting that timing may be crucial for maximizing benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Will Delaying Breakfast Mitigate the Metabolic Health Benefits of Time-Restricted Eating? Heilbronn, LK., Regmi, P.[2021]

In a 12-week study involving 23 obese adults, time-restricted feeding (TRF) with an 8-hour eating window was found to be safe, as there were no significant changes in self-reported adverse events or disordered eating patterns.

The study suggests that TRF can effectively support weight loss in obese individuals without negatively impacting their health or body image perception.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of 8-h time restricted feeding in adults with obesity. Gabel, K., Hoddy, KK., Varady, KA.[2019]

In a pilot study involving 25 college students, early time-restricted eating (eTRE) with a 6-hour eating window showed potential benefits for weight reduction and improved diet quality by reducing the consumption of energy-dense foods typically eaten late at night.

Although the study was disrupted by COVID-19, preliminary results from 18 participants suggest that eTRE may be a feasible approach to enhance dietary habits, warranting further research to explore individual preferences and nutrition recommendations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The feasibility and preliminary efficacy of early time-restricted eating on diet quality in college students: A randomized study. Mayra, ST., Chondropoulos, K., De Leon, A., et al.[2022]

Time-restricted eating (TRE) is a promising dietary approach that not only aids in weight management but also positively influences energy metabolism, gut microbiota, and overall homeostasis.

Chronodisruption, which occurs when our internal circadian rhythms are out of sync with external cues, is linked to serious health issues like metabolic disorders and cancer, highlighting the importance of aligning eating patterns with our biological clocks.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Time-restricted eating for chronodisruption-related chronic diseases. Cheng, WY., Desmet, L., Depoortere, I.[2023]

Constant light exposure (LL) significantly disrupts circadian rhythms in metabolic processes, particularly affecting the liver more severely than white adipose tissue (WAT), leading to increased body weight despite similar food intake.

Time-restricted feeding during LL can partially restore circadian rhythms in both liver and WAT, suggesting a potential strategy to mitigate the negative effects of constant light on metabolism.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Peripheral circadian rhythms in the liver and white adipose tissue of mice are attenuated by constant light and restored by time-restricted feeding. Yamamuro, D., Takahashi, M., Nagashima, S., et al.[2020]

In the CALERIE study, calorie restriction (CR) led to significant weight loss, explaining 41% of the variance in weight loss among participants, but the timing of meals also played a crucial role.

Shorter eating intervals and consistent timing for the first and last meals were associated with greater weight loss and enhanced adherence to CR, suggesting that optimizing meal timing could improve the effectiveness of CR protocols.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Associations between the timing of eating and weight-loss in calorically restricted healthy adults: Findings from the CALERIE study. Fleischer, JG., Das, SK., Bhapkar, M., et al.[2022]

Time-restricted eating (TRE), which limits calorie intake to 6- to 10-hour periods during the active part of the day, has been shown to improve various aspects of metabolic health, including weight loss, glucose tolerance, and cardiovascular health, based on both preclinical and human studies.

Implementing TRE can help mitigate the negative effects of eating out of sync with our body's natural circadian rhythms, potentially reducing the risk of chronic diseases, although there are challenges in applying this dietary approach in real-world settings.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Time-Restricted Eating: Benefits, Mechanisms, and Challenges in Translation. Regmi, P., Heilbronn, LK.[2021]

Citations

1. nature.com nature.com/articles/s41598-024-83789-3

A systematic review and meta-analysis on light therapy for ... The results showed that light therapy significantly improved the total sleep time (TST) (MD = 32.54, p < 0.00001) and sleep efficiency (SE) (MD ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC2764401/

Effect of Light Treatment on Sleep and Circadian Rhythms ... Increasing exposure to morning bright light delayed the acrophase of the activity rhythm and made the circadian rhythm more robust.

3. stanfordhealthcare.org stanfordhealthcare.org/medical-conditions/sleep/advanced-sleep-phase-syndrome/treatments/bright-light-therapy.html

Bright Light Therapy Bright light therapy is used to manage circadian rhythm disorders such as delayed sleep phase syndrome (DSPS), a condition which shifts the normal sleeping ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S1087079218301886

Light therapies to improve sleep in intrinsic circadian ... Overall, the effects of light schedule interventions on sleep outcomes were positive. We found evidence of small but statistically and clinically significant ...

5. jamda.com jamda.com/article/S1525-8610(22)00790-3/fulltext

Light Therapy to Improve Sleep Quality in Older Adults ... Light therapy has been reported to be effective for improving the sleep of healthy older people, and patients with dementia or Parkinson's ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC2679862/

A Clinical Approach to Circadian Rhythm Sleep Disorders - PMC The most commonly recommended approach is broad spectrum bright light of 2,000–10,000 lux early morning (6–8 a.m.) for about 1–3 hours. In clinical practice, ...

7. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0885392425005901

Effectiveness and Safety of Bright Light Therapy in ... Bright light therapy (BLT) is an effective approach to treat different conditions. ... BLT is well-tolerated, easy to administer and has relatively low costs.

8. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6746555/

Bright Light Therapy: Seasonal Affective Disorder and Beyond Morning BLT treatment corrects the phase delay by shifting the circadian rhythm earlier (to the left) leading to less discordance between the circadian rhythm ...