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.

NCT07339592 | Enrolling By Invitation

• 1 other identifier: University of Jordan 491/2025
• Study Type: interventional
• Target: 90
• Locations: 1 country
• Sites: 1

Brief Summary

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. 1.High-carbohydrate last meal (≈80% of dinner calories from carbohydrates),
2. 2.High-protein last meal (≈40-50% of dinner calories from protein),
3. 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.

Conditions

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

Outcome Measures

Primary Outcomes (1)

• Change in Sleep Quality (PSQI Global Score)

  Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI) before and after the 2-week intervention. The PSQI total score (0-21) will quantify subjective sleep quality; higher scores indicate poorer sleep

  Baseline and 2 weeks post-intervention

Secondary Outcomes (6)

• Change in CLOCK Gene Expression

  Baseline and 2 weeks post-intervention

• Change in BMAL-1 Gene Expression

  Baseline and 2 weeks post-intervention

• Change in Total Sleep Duration

  1 week baseline and 2 weeks during intervention

• Change in Sleep Efficiency

  1 week baseline and 2 weeks during intervention

• Change in Sleep Stage Distribution

  1 week baseline and 2 weeks during intervention

Study Arms (3)

High-Carbohydrate Last Meal

EXPERIMENTAL

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

Dietary Supplement: High-Carbohydrate Last Meal

High-Protein Last Meal

EXPERIMENTAL

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

Dietary Supplement: High-Protein Last Meal

Balanced Standard last meal

ACTIVE COMPARATOR

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

Dietary Supplement: Balanced Standard Dinner

Interventions

High-Carbohydrate Last Meal DIETARY_SUPPLEMENT

Dinner ≈30% daily kcal; \~80% carb; taken 3-4 h before sleep for 2 weeks

High-Carbohydrate Last Meal

High-Protein Last Meal DIETARY_SUPPLEMENT

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

High-Protein Last Meal

Balanced Standard Dinner DIETARY_SUPPLEMENT

Standard macronutrient distribution; same timing (3-4h pre-sleep) and 2-week duration.

Balanced Standard last meal

Eligibility Criteria

• Age: 25 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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).

Sponsors & Collaborators

• University of Jordan: lead

Study Sites (1)

University of Jordan Hospital

Amman, Jordan

Location

MeSH Terms

Conditions

Sleep Initiation and Maintenance Disorders

Condition Hierarchy (Ancestors)

Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Nervous System Diseases; Mental Disorders

Study Officials

• Hadeel A Ghazzawi, professor

  The University of Jordan School of Agriculture

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Prof.

Study Record Dates

• First Submitted: December 16, 2025
• First Posted: January 14, 2026
• Study Start: December 1, 2025
• Primary Completion: January 1, 2026
• Study Completion: May 1, 2026
• Last Updated: January 14, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

JO (1)