This Trial Examines How Last Meal Composition and Timing Affect Sleep Quality and Circadian Gene Expression Among Medical Residents. Recruitment Not Yet Started; Study Begins Dec 2025 and Ends Dec 2026. (CHRONO-MED)

University of Jordan

Status: Invitation-only

Conditions: Nutrition Intake; Circadian Rhythm; Sleep Quality; Medical Residents; Meal Timing

Treatments: Dietary Supplement: Balanced Standard Dinner; Dietary Supplement: High-Protein Last Meal; Dietary Supplement: High-Carbohydrate Last Meal

Study type: Interventional

Funder types: Other

Identifiers

NCT07339592

University of Jordan 491/2025

Details and patient eligibility

About

This randomized controlled trial aims to evaluate the effects of last meal composition and timing on sleep quality and circadian gene expression among medical residents in Jordanian hospitals. Sleep disturbances are common in this population due to long working hours, high stress, and irregular eating schedules. Chrono-nutrition, the science of aligning food intake with circadian rhythms, may provide a practical approach to improving sleep and overall well-being.

Participants will be randomly assigned to one of three groups:

1. High-carbohydrate last meal (≈80% of dinner calories from carbohydrates),
2. High-protein last meal (≈40-50% of dinner calories from protein),
3. Control group consuming a balanced standard meal. Each participant will consume the assigned meal 3-4 hours before bedtime for two weeks. Sleep quality will be measured using the Pittsburgh Sleep Quality Index (PSQI) and smartwatch-derived parameters, while salivary samples collected pre- and post-intervention will be analyzed for CLOCK and BMAL1 gene expression. The study will also include dietary, anthropometric, and physical activity assessments.

This study has been approved by the Institutional Review Board of the University of Jordan (IRB No. 491/2025). Recruitment has not yet started. Enrollment is expected to begin in December 2025, with primary data collection completed by June 2026 and final study completion by December 2026.

Enrollment: 90 estimated patients

Sex: All

Ages: 25+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Currently enrolled and working in Jordanian hospitals.
• Not currently following a specific diet or weight-loss program.
• Willing to comply with study protocol and intervention meals for two weeks. Provide written informed consent before participation.

Exclusion criteria

• Presence of any chronic medical condition (e.g., diabetes, thyroid disorders, gastrointestinal, cardiovascular, or respiratory diseases).
• Diagnosed sleep disorders, such as insomnia, sleep apnea, or restless legs syndrome.
• Mental health disorders (stress, anxiety, or depression diagnosed or medicated).
• Pregnancy or lactation.
• Use of medications or herbal supplements known to affect sleep (e.g., melatonin, chamomile, ashwagandha, lavender).
• Caffeine dependence exceeding moderate levels ( >400 mg caffeine/day).

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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90 participants in 3 patient groups

High-Carbohydrate Last Meal

Experimental group

Description:

Dinner ≈30% of daily kcal; \~80% of dinner kcal from carbs; consumed 3-4 h before sleep for 2 weeks.

Treatment:

Dietary Supplement: High-Carbohydrate Last Meal

High-Protein Last Meal

Experimental group

Description:

≈30% of daily kcal; \~38-54% of dinner kcal from protein; consumed 3-4 h before sleep for 2 weeks.

Treatment:

Dietary Supplement: High-Protein Last Meal

Balanced Standard last meal

Active Comparator group

Description:

Standard balanced dinner (per usual guidelines), same timing (3-4 h pre-sleep) and 2 weeks duration.

Treatment:

Dietary Supplement: Balanced Standard Dinner