Novel Approach to Assess Metabolic Flexibility in a Respiratory Chamber

Study Overview
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Brief Summary
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The overarching aim of this study: To determine the effect of different meal compositions (high- vs. low-fat) on metabolic flexibility as it relates to meal-stimulated change in respiratory quotient (ΔRQ1) and sleep (ΔRQ2) metabolic flexibility, as well as the time course changes in respiratory quotient, RQ (i.e., peak RQ, time to peak RQ, nadir RQ, time to nadir, slope).

Official Title
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Novel Approach to Assess Metabolic Flexibility in a Respiratory Chamber

Conditions
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Diabetes Mellitus, Type 2

Intervention / Treatment
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* Other: High fat meal
* Other: Low fat meal


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Eligibility criteria include: Healthy male or female Ages 18-40 y BMI between 20 kg/m2 and 30 kg/m2 (±0.5 kg/m2 will be accepted) Are willing to consume pre-prepared meals Are willing to maintain current physical activity, sleep schedule, and dietary habits during the study. Medically cleared for participation in the study by Medical Investigator Exclusion Criteria: Participants are ineligible to participate (or will be excluded from participating in this study) if they meet any of the following criteria: Unstable weight in the last 3 months [gain or loss >7 lb (or 3.2 kg)] Currently working shift work Smoking or use of tobacco products within the last 3 months Amenorrhea (or absence of regular monthly cycles) History of clinically diagnosed diabetes or a fasting blood glucose >126 mg/dL Average screening blood pressure >140/90 mmHg Previous bariatric surgery (or other surgeries) for obesity or weight loss Use of medications affecting metabolism or sleep History of neurological disease History of cardiovascular disease (or other chronic diseases) Pregnant, planning to become pregnant, or breastfeeding Adherence to special restrained diets (e.g., low-carbohydrate, low-fat, or vegetarian/vegan diets) over the last 3 months.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High Fat Meal First<br>Arm 1 participants randomized to receive high fat meal first, and low fat meal second | Other: High fat meal<br>* 60% fat meal<br>Other: Low fat meal<br>* 20% fat meal<br>|
| Experimental: High Fat Meal Second<br>Arm 2 participants randomized to receive low fat meal first, and high fat meal second | Other: High fat meal<br>* 60% fat meal<br>Other: Low fat meal<br>* 20% fat meal<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Overnight Respiratory Exchange Ratio | 12-h mean of respiratory exchange ratio following each meal type. measurement interval = 12h following start of meal (7pm) The respiratory exchange ratio refers to the proportion of macronutrients being oxidized. A respiratory exchange ratio value of 1.0 indicates only carbohydrates are being oxidized, while a ratio value of 0.7 indicates only fats are being oxidized. Intermediate values, such as 0.85, indicates that both carbohydrate and fats are being oxidized. | 12 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep Respiratory Exchange Ratio | mean of respiratory exchange ratio following each meal type during sleep period, 2am-5am., 2am-5am. measurement interval = 3h (2am-5am) The respiratory exchange ratio refers to the proportion of macronutrients being oxidized. A respiratory exchange ratio value of 1.0 indicates only carbohydrates are being oxidized, while a ratio value of 0.7 indicates only fats are being oxidized. Intermediate values, such as 0.85, indicates that both carbohydrate and fats are being oxidized. | 3 h | 
| Peak Increase in Respiratory Exchange Ratio | mean of peak increase in respiratory exchange ratio (Peak values - baseline values) following each meal type Peak values were defined as the peak respiratory exchange ratio value measured during the post-meal period, 6pm-10pm. Baseline values were measured 1h prior to meal (5:00-5:45pm) measurement interval of peak values= 4h (6pm-10pm) A larger value in this measurement indicates that more carbohydrate than fats were being oxidized as fuel during the measurement period. | 4 h | 
| Peak Decrease in Respiratory Exchange Ratio | mean of peak decrease in respiratory exchange ratio (baseline values -nadir values) following each meal type Peak values were defined as the peak respiratory exchange ratio value measured during the post-meal period, 6pm-10pm. Baseline values were measured 1h prior to meal (5:00-5:45pm) measurement interval of nadir values= 12h (6pm-6am) A larger value in this measurement indicates that more fats than carbohydrate were being oxidized as fuel during the measurement period. | 12 h | 
| Time to Peak Respiratory Exchange Ratio | Average time from meal to peak respiratory exchange ratio value This measurement indicates how long on average it took form the onset of the meal, 6pm, for the participants to achieve their highest/peak respiratory exchange ratio value. | 12 h | 
| Time to Nadir Respiratory Exchange Ratio | Average time from meal to nadir respiratory exchange ratio value This measurement indicates how long on average it took form the onset of the meal, 6pm, for the participants to achieve their lowest/nadir respiratory exchange ratio value. | 12 h | 
| Slope of Respiratory Exchange Ratio | This value indicates the speed and magnitude of the participants change in respiratory exchange ratio between the peak and nadir values. A more negative value in this measurement indicates either a short time interval between the highest and lowest respiratory exchange ratio values measured and/or a large difference between the highest and lowest values of respiratory exchange ratio values measured. | 12 h |