A Study to Assess the Effect of a Normal vs. High Protein Diets in Carbohydrates Metabolism in Obese Subjects With Diabetes or Prediabetes

Study Overview
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Brief Summary
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The objective of the study is to assess the effect of low-calorie diets with normal (18%) vs. high (35%) protein (mainly coming from animal source) composition on body weight and carbohydrates metabolism in overweight and obese subjects with pre-diabetes or diabetes. A dietary intervention is carried out during 6 months in 100 subjects who are individually randomized to an energy-restricted diet with two types of macronutrients composition: 1) 35% protein, 30% fat and 35% carbohydrates and 2) 18% protein, 30% fat and 52% carbohydrates. Around 80% of total protein in diet comes from animal source (of whom around 40% from lean red meat). Subjects are provided with weekly menus and different recipes to use them as part of the diet. Monitoring visits with the nutritionist will be performed every 15 days. At the beginning of the study, after 3 and 6 months, the following parameters are determined: anthropometric (weight, waist circumference, body mass index and body composition), blood pressure, dietary (72-hours dietary registry) and exercise and biochemical analysis (total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, apolipoproteins A1 and B, iron, transferring, ferritin, uric acid, glucose, HbA1c, insulin, adiponectin and resistin). Urine samples are also collected to assess microalbuminuria and ureic nitrogen.

Official Title
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A Study to Assess the Effect of a Normal vs. High Protein Diets in Carbohydrates Metabolism in Obese Subjects With Diabetes or Prediabetes

Conditions
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Weight Loss, Obesity, Diabetes, Diet, Reducing, Carbohydrates, Protein

Intervention / Treatment
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* Behavioral: Weight loss interventional study with a low-calorie 18%-protein diet
* Behavioral: Weight loss interventional study with a low-calorie 35%-protein diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 18-70 years old. Body mass index between 27.5 - 40. Steady weight (± 4 kg) in the last 2 months. Glycated hemoglobin between 6 - 7%. Exclusion Criteria: Anti-diabetic drugs (oral or subcutaneous) in the last 2 months. Lipid-lowering drugs in the last 2 months. Gouty arthritis in the last 2 years or uric acid > 735 mg/dl. Presence of uncontrolled endocrinological pathology (including hypothyroidism). Hepatic chronic disease (glomerular filtration rate < 45 ml/min). Renal, inflammatory or tumoral diseases. Drugs which could interfere in glucose or lipid metabolism such as androgens, corticosteroids (except for those with topic administration) and estrogen replacement therapy. Intake of functional foods with plant sterols in the past 6 weeks. High alcohol intake (> 30 g per day). Any serious disease which involves less than 1 year life expectancy or, in investigators judgment, limit the follow-up of an homogeneous diet throughout the study. Pregnancy or intention of pregnancy during the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 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: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 18%-Protein diet<br>Energy-restricted diet wit the following composition: 18% protein, 30% fat and 52% carbohydrates | Behavioral: Weight loss interventional study with a low-calorie 18%-protein diet<br> <br> |
| Active Comparator: 35%-Protein diet<br>Energy-restricted diet wit the following composition: 35% protein, 30% fat and 35% carbohydrates | Behavioral: Weight loss interventional study with a low-calorie 35%-protein diet<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in glucose. |  | After 3 and 6 months of intervention. | 
| Change in glycated hemoglobin. |  | After 3 and 6 months of intervention. | 
| Change in insulin resistance (HOMA index). |  | After 3 and 6 months of intervention. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body weight. |  | After 3 and 6 months of intervention. | 
| Change in body composition. |  | After 3 and 6 months of intervention. | 
| Change in waist circumference. |  | After 3 and 6 months of intervention. | 
| Change in lipid profile (total cholesterol, LDL cholesterol, HDL cholesterol, non HDL cholesterol, triglycerides and apolipoproteins). |  | After 3 and 6 months of intervention. |