Low-fat dietary intervention: 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).
High-fat dietary intervention: 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).
Study 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.
Eligibility
Sex
ALL
Min age
18 Years
Max age
32 Years
Healthy volunteers
Accepted
Inclusion Criteria:
* 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
Exclusion Criteria:
* 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
Primary outcome measure(s)
Sleep Architecture and Neurophysiological Features — Up to 9 nights on each diet Objective registration and analysis of sleep, based on polysomnography or validated wearable devices to capture macrosleep, spectral and microsleep features.
Change in 24-Hour Heart Rate Variability (HRV) — Up to 9 days on each diet 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.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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