How a Western versus a fiber-rich diet affects sleep and daily body rhythms

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a randomized crossover experiment where each participant follows two different diets (Western-style high-fat versus a healthier, fiber-rich diet) with about a week of at-home monitoring followed by a multi-day stay in the lab under controlled conditions. Sleep will be measured objectively with polysomnography and with wearable devices, while continuous glucose monitoring, heart rate, and blood pressure will capture 24-hour physiological patterns. Repeated biological sampling across the day will measure hormonal, cardiometabolic, neurodegenerative, and gut microbial biomarkers, and cognitive performance, mood, and appetite will also be recorded. Comparing the same people on both diets will help isolate direct diet-driven changes in sleep and related physiology.

Why it matters

Who can join: the full rules

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

Where it's running

• Uppsala biomedical center
  Uppsala, Sweden Recruiting

Study contacts

• Principal investigator: Jonathan Cedernaes, MD, PhD — Uppsala University, Sweden
• Study coordinator: Jonathan Cedernaes, MD, PhD
• Email: jonathan.cedernaes@medsci.uu.se
• Phone: 0184710000

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.