Dietary Impact on Sleep, Rhythms and Related Physiology

NCT07138313 | Recruiting

• 1 other identifier: CircHFJC2017pt2
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 1

Brief Summary

Sleep and metabolism are closely interconnected, and emerging evidence suggests that dietary composition may influence both sleep quality and key physiological functions such as glucose regulation, cardiovascular activity, and hormonal signaling. This study aims to investigate how a Western-style unhealthy diet versus a healthier, fiber-rich diet affects objective and subjective sleep measures, 24-hour physiological parameters, and a range of biomarkers related to cardiometabolic, neurodegenerative, and gut microbial function.

Conditions

Sleep; Diet Interventions; Circadian Rhythm

Outcome Measures

Primary Outcomes (2)

• Sleep Architecture and Neurophysiological Features

  Objective registration and analysis of sleep, based on polysomnography or validated wearable devices to capture macrosleep, spectral and microsleep features.

  Up to 9 nights on each diet

• Change in 24-Hour Heart Rate Variability (HRV)

  Continuous measurement of HRV, using a wearable device, focused on the metric Root Mean Square of the Successive Differences (RMSD); additional metrics (Standard Deviation of NN intervals (SDNN), low frequency to high frequency (LF/HF) ratio) analyzed for exploratory purposes.

  Up to 9 days on each diet

Secondary Outcomes (24)

• 24-Hour Heart Rate (HR)

  Up to 9 days on each diet

• Heart Rate Response to Standardized Stair Stepping

  Baseline and day 7-9 of each diet period

• Morning-to-Evening and 24-h blood pressure (BP)

  Up to 9 days on each diet

• 24 Hour Continuous Glucose Levels

  Up to 9 days on each diet

• Levels of Blood-based Biomarkers

  Up to 9 days on each diet

Study Arms (2)

Healthy diet

EXPERIMENTAL

'Low-fat dietary intervention' to be administered to participants

Other: Low-fat dietary intervention

Unhealthier diet

EXPERIMENTAL

'High-fat dietary intervention' to be administered to participants

Other: High-fat dietary intervention

Interventions

Low-fat dietary intervention OTHER

Low-fat diet for approximately 1 week, preceding in-lab study period (approximately 2 days) under standardized conditions (total dietary exposure up to 9-10 days).

Healthy diet

High-fat dietary intervention OTHER

High-fat diet for approximately 1 week, preceding in-lab study period (approximately 2 days) under standardized conditions (total dietary exposure up to 9-10 days).

Unhealthier diet

Eligibility Criteria

• Age: 18 Years - 32 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age 18-32 yr
• Healthy (self-reported) and not on chronic medication
• BMI 18-27 kg/m2 (and waist circumference \<102 cm), and weight stable (less than 5% body weight change in the past 6 months)
• Non-smoker and non-nicotine user
• Regular sleep-wake pattern, with sleep duration of 7-9.25 hrs per night
• Regular exercise habits the last 2 months
• Regular daily meal pattern with 3 main meals

You may not qualify if:

• Major or chronic illness, e.g. diabetes, renal disease or inflammatory bowel disease
• Current or history of endocrine or metabolic disorders
• Psychiatric or neurological disorders (e.g. bipolar disorder, epilepsy)
• Frequent gastrointestinal symptoms
• Chronic medication
• Any sleep disorder (including recent or chronic symptoms of insomnia)
• Shift work in the preceding three months or for a long duration
• Extreme chronotype or physical activity patterns
• Time travel over two time zones in the preceding month
• Too much weight gain or weight loss in the preceding 6 months (±5% body weight in past 6 months)
• Any issues with or allergies against the provided food items
• Recent major dietary changes or adoption of specific dietary regimens
• Women who are pregnant, breastfeeding, or planning to become pregnant during the study period.
• Use of illicit drugs or substances of abuse

Sponsors & Collaborators

• Uppsala University: lead

Study Sites (1)

Uppsala biomedical center

Uppsala, 75324, Sweden

RECRUITING

Study Officials

• Jonathan Cedernaes, MD, PhD

  Uppsala University, Sweden

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jonathan Cedernaes, MD, PhD

CONTACT

0184710000; jonathan.cedernaes@medsci.uu.se

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: In the crossover condition, participants will not be briefed about what diet they will receive before the actual onset of any of the two dietary interventions
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants will be studied in a crossover design both after a "healthy diet", and after an "unhealthy diet"

Study Record Dates

• First Submitted: July 4, 2025
• First Posted: August 22, 2025
• Study Start: September 22, 2025
• Primary Completion (Estimated): July 31, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: February 4, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

SE (1)