Effect of Dietary Habits on Metabolic Health

Study Overview
=================
Brief Summary
-----------------
The goal of this application is to understand the connection between people's eating habits and the risk for developing diabetes, obesity, and cardiovascular disease.

Detailed Description
-----------------
More than a third of U.S. adults are obese (BMI greater than 30), 8-12% of adults suffer from type 2 diabetes, and up to 30% of adults have pre-diabetes. Recent research studies have suggested that it is not just what we eat, but also when we eat that may put us at risk for obesity and type 2 diabetes. Skipping breakfast and eating late at night have been associated with an increased risk for obesity and type 2 diabetes (T2D), substantiated by recent animal and human experimental studies showing that altered meal timing itself, without changes in caloric intake, can influence weight regulation and impaired glucose tolerance. This research will determine in prediabetic and non-diabetic participants whether delaying meal times worsens glucose tolerance, leads to physiological changes favoring a positive energy balance, and increases caloric intake. This research will provide mechanistic insights into the metabolic consequences of changing meal timing and may help in evidence-based approaches to improve dietary interventions in the fight against obesity and T2D.

Official Title
-----------------
Effect of Dietary Habits on Metabolic Health

Conditions
-----------------
Overweight, Obesity, Prediabetes, Meals

Intervention / Treatment
-----------------
* Behavioral: Meal schedule


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: BMI between 25 and 37.9 kgm-2 Adults with regular sleep-wake timing Non-smokers Completion of medical and psychological screening tests Able to spend 14 consecutive days in the sleep laboratory Exclusion Criteria: BMI < 25 or > 37.9 kgm-2 History of neurological or psychiatric disorder History of sleep disorder or regular use of sleep-promoting medication Current prescription, herbal, or over-the-counter medication use Traveling across 2 or more time zones within past 3 months Donating blood within past 8 weeks Worked night or rotating shift work within past 3 years Hearing impairment Drug or alcohol dependency

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Early Meals<br>Meals are eaten early in the wake episode | Behavioral: Meal schedule<br> <br> |
| Experimental: Late Meals<br>Meals are eaten late in the wake episode | Behavioral: Meal schedule<br> <br> |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in plasma leptin levels across sleep/wake cycle | Frequent blood samples | During standardized meals scheduled on Days 3 and 6 | 
| Change in circadian profile of plasma leptin | Frequent blood samples | During constant routine (Days 7-8) | 
| Change in glucose tolerance | Frequent blood samples | During standardized meals scheduled on Days 3 and 6 | 
| Change in circadian profile of plasma glucose levels | Frequent blood samples | During constant routine (Days 7-8) | 
| Change in plasma insulin levels after standardized test meal | Frequent blood samples | During standardized meals scheduled on Days 3 and 6 | 
| Change in circadian profile of plasma insulin levels | Frequent blood samples | During constant routine (Days 7-8) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in circadian phase markers, such as from core body temperature, melatonin, cortisol | Core temperature and frequent blood samples | During constant routine (Days 7-8) | 
| Changes circadian rhythm in resting energy expenditure | Indirect calorimetry | During constant routine (Days 7-8) | 
| Change in hunger and appetite, mood, and cognitive performance | Subjective ratings and cognitive tests performed via computer interface | Tests taken throughout the protocol, Days 1-9 | 
| Changes in microbiota, gene expression, epigenetic or proteomic markers | Frequent blood samples and saliva samples | Throughout the protocol during Days 3 and 6, and during constant routine (Days 7-8) | 
| Changes in sleep | Polysomnography | Sleep will be measured during the night after Days 2 and 5 | 
| Change in insulin sensitivity, gene expression, epigenetic, lipidomic or proteomic markers from isolated adipocytes | 2 fat biopsies, one sample will be taken during each protocol | On Day 5 of each protocol | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Dietary Habits, Circadian, Metabolism, Feeding Behavior