Effects of a Wholegrain Diet on Body Composition and Energy Balance

Study Overview
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Brief Summary
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The purpose of this study is to compare a diet containing whole grains versus an energy matched diet using refined grains on body composition and metabolism.

Detailed Description
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The investigators hypothesis is that a diet high in whole-grains reduces abdominal fat. These findings might have clinical and public health significance for reducing obesity and related co-morbidities like type 2 diabetes and cardiovascular disease. Using a double-blind cross-over design, energy expenditure, body composition and metabolic health will be assessed. Three day inpatient study visits to the Cleveland Clinic Clinical Research Unit (CRU) will be implemented for metabolic control and testing. Total daily energy expenditure will be measured using the doubly labeled water (DLW) method. Body fat and glucose/protein metabolism will be assessed by imaging and isotope techniques, respectively. Blood, urine, and stool samples will also be collected for cardiometabolic and digestive health outcomes. After baseline testing, subjects will begin an 8 week dietary intervention, where all food and non-water beverages will be supplied by the study center. Dietary compliance will be assessed by weigh back measurements two times a week. To assess time course effects of diets differing in the amount of fiber on body composition and metabolic health, subjects will provide plasma and urine samples 2, 4, and 8 weeks after initial testing. Imaging and isotope analysis will be performed baseline and at week 8. All post testing will be conducted after week 8 following similar pre-testing control conditions. Subjects will then undergo an 8-10 week washout period where they will be instructed to return to their normal diet (except for any supplements). After the washout period, subjects will start the second arm of the intervention and consume the alternate diet (i.e. refined or whole grain diet). All energy expenditure, body composition and metabolic testing procedures will be repeated during the alternative arm of the study as described above.

Official Title
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Effects of Diet on Body Composition

Conditions
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Overweight, Obesity, Pre-diabetic

Intervention / Treatment
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* Dietary Supplement: Whole grains


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged between 20-50 years BMI between 25 and 38 kg/m2 Normal whole grain intake <1 serving/d (Appendix 1) Low average consumption of alcohol (<1 standard drink/day; <7 standard drinks/week) Non-smoker No major chronic illness Fasting glucose <126 mg/dl Able to access the study centre (Lerner Research Institute and the Clinical Research Unit at the Cleveland Clinic) throughout the study Have access to a microwave oven and refrigerator/freezer Exclusion Criteria: Any known food allergy with the possibility to result in a serious adverse reaction, or an allergy to a food item that cannot be removed from the diet (i.e. peanuts). Aversion or dislike to study foods Regular use of dietary supplements and not willing/able to stop usage during the study period Cardiovascular conditions including significant known coronary artery disease, arrhythmia, known peripheral vascular disease (large vessel disease), uncompensated congestive heart failure, history of stroke, or uncontrolled hypertension (defined as medically treated with the mean of 3 separate measurements SBP > 180 mm Hg or DBP > 110 mm Hg) Severe pulmonary disease defined as FEV1 < 50% of predicted value Kidney disease including diagnosed chronic kidney disease, renovascular hypertension, renal artery stenosis, or chronic renal insufficiency with a creatinine level > 1.8 mg/dl Known history of chronic liver disease (except for NAFLD), hepatitis, positive serologic test result for hepatitis B surface antigen and/or hepatitis C antibody, α-1-antitrypsin deficiency GI disorders including a known history of celiac disease and/or any other malabsorptive disorders or inflammatory bowel disease (Crohn's disease or ulcerative colitis) Psychiatric disorders including dementia, active psychosis, severe depression (requiring > 2 medications), history of suicide attempts, alcohol or drug abuse within the previous 12 months Other known metabolic disease such as clinical hypothyroidism and hyper thyroidism, Graves Disease, thyroid cancer, nodules or multinodular goiter Malignancy within five years (except squamous cell and basal cell cancer of the skin)

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 50 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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Whole grain diet<br>Subjects will eat a whole grain based diet for eight weeks. Pre-and post-diet intervention testing will determine effects on body composition. Whole grain-based are will be compared to the refined grain based diet. | Dietary Supplement: Whole grains<br>* Comparison of a diet containing whole grain compared to an energy matched diet based on similar foods, but using refined grains.<br>* Other names: Body composition;|
| Active Comparator: Refined grain diet<br>Subjects will eat a refined grain diet for 8 weeks matched with the whole grain arm for calorie and macro nutrient intake. Pre-and post-diet testing will determine effects on body composition. | Dietary Supplement: Whole grains<br>* Comparison of a diet containing whole grain compared to an energy matched diet based on similar foods, but using refined grains.<br>* Other names: Body composition;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body composition | The primary outcome is the change in body composition after an eight-week intervention of either whole grains or refined grains, corrected for baseline body composition at the start of the appropriate treatment arm. | 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total energy expenditure | DLW will be used to assess total daily energy expenditure (TDEE). | Eight-week cross-over trial with 10 week washout period between intervention arms. | 
| Glucose turnover | Glucose turnover will be assessed by [U-13C] glucose and [6,6-(2)H] glucose kinetics from breath, plasma and urine samples. | Eight weeks | 
| Protein turnover | Protein turnover will be examined using 13C-leucine and 15N-glycine kinetics in breath, plamsa, and urine samples. | Eight weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Body composition, Health markers, Diet