A Very High Fiber Diet Versus a Low-carbohydrate Diet for Weight Loss

Study Overview
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Brief Summary
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Using a 2x2 complete factorial design, approximately 140 obese men and women who may or may not have type 2 diabetes will be randomized to one of two conditions (70 in each condition): (a) a high fiber diet, or (b) a low-carbohydrate diet. Participants will be instructed to follow their assigned diets for 1 year. Outcome measures of interest will include participants' BMI, waist circumference, blood lipids (total, HDL, and LDL cholesterol, and triglycerides), C-reactive protein, and gastrointestinal peptides. Participants will be recruited from the Loma Linda and San Bernardino city area in southern California.

Official Title
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A Very High Fiber Diet Versus a Low-carbohydrate Diet for Weight Loss in Obese Individuals With or Without Type 2 Diabetes

Conditions
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Obesity, Type 2 Diabetes

Intervention / Treatment
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* Other: High fiber vs. low-carbohydrate diets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI 30.0-42.0 kg/m2 English-speaking Exclusion Criteria: Pregnancy Lactation Acute or chronic infection Type 1 diabetes Participation in another trial Active cancers Currently using Byetta Currently on weight loss medication Weight loss of more than 4 lbs. within the last 3 months Vegan Active eating disorder Gastrointestinal problems that may be worsened by a high fiber intake

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High fiber diet<br> | Other: High fiber vs. low-carbohydrate diets<br>* High fiber diet involves at least 40 grams of dietary fiber or more per day for women and at least 50 grams of dietary fiber per day for men. Low-carbohydrate diet involves less than 120 grams of carbohydrate per day for both men and women.<br>|
| Experimental: Low-carbohydrate diet<br> | Other: High fiber vs. low-carbohydrate diets<br>* High fiber diet involves at least 40 grams of dietary fiber or more per day for women and at least 50 grams of dietary fiber per day for men. Low-carbohydrate diet involves less than 120 grams of carbohydrate per day for both men and women.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Weight |  | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lipid profiles |  | 1 year | 
| Gastrointestinal hormones |  | 1 year | 
| Waist circumference |  | 1 year | 
| C-reactive protein |  | 1 year | 
| Blood glucose |  | 1 year | 
| Serum insulin |  | 1 year | 
| Hemoglobin A1c |  | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Type 2 diabetes, Fiber, Dietary fiber, Low-carbohydrate diet, High protein diet