The Influence of Overfeeding Different Macronutrients on Whole-body Insulin Sensitivity

Study Overview
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Brief Summary
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This study will investigate the effect of high-carbohydrate vs. high-fat overfeeding (130% of energy requirements) on whole body insulin sensitivity. Following habitual diet, participants will be randomly allocated to either a high-carbohydrate or a high-fat diet intervention for 14-days. On days 0, 7 and 14 participants will undergo anthropometric and metabolic testing (primarily an oral glucose tolerance test [OGTT]).

Official Title
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The Influence of Overfeeding Different Macronutrients on Whole-body Insulin Sensitivity

Conditions
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Insulin Resistance, Type 2 Diabetes, Glucose Metabolism Disorders, Metabolic Disease

Intervention / Treatment
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* Other: High-fat diet
* Other: High-carbohydrate diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-40 years BMI = 18.5-29.9 kg/m2 Male or female Physically active (> 3 x 30 min moderate exercise per week) Non-smoker (including the use of vaporisers and e-cigarettes) Healthy (determined by the School's standard health questionnaire) No cardiometabolic or inflammatory illness Exclusion Criteria: Outside of age-range Outside BMI range Inactive (< 3 x 30 min moderate exercise per week) Smoker Taking medication History of cardiometabolic or inflammatory illness Vegetarian/ vegan (as the high-fat diet is based on animal fats) Other dietary restrictions which prevent consumption of the experimental diet Consumption of probiotics within last 3 months (these influence the gut microbiota) Participation in another clinical trial Those with known or suspected food intolerances, allergies or hypersensitivity Women who are known to be pregnant or who are intending to become pregnant over the course of the study

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: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: High-fat diet<br>Participants will consume a diet rich in fat (approximately 65% of total energy) and low in carbohydrate for 14 days. Measurements will be made at 0, 7 and 14 days. | Other: High-fat diet<br>* Participants will consume a high fat diet for 14 days with approximately 65% of energy from fat. The diet will also provide an energy excess, at 130% of energy requirements. Participants will be provided with all of their meals and snacks throughout the study.<br>|
| Active Comparator: High-carbohydrate diet<br>Participants will consume a diet rich in carbohydrate (approximately 70% of total energy) and low in fat for 14 days. Measurements will be made at 0, 7 and 14 days. | Other: High-carbohydrate diet<br>* Participants will consume a high fat diet for 14 days with approximately 70% of energy from carbohydrate. The diet will also provide an energy excess, at 130% of energy requirements. Participants will be provided with all of their meals and snacks throughout the study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Whole-body insulin sensitivity index | Assessed by oral glucose tolerance test | The change between pre-, during and post- dietary interventions: Assessed on days 0, 7 and 14 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body Mass Index | Calculated from height and weight | Day 0, Day 7, Day 14 | 
| Fasting plasma glucose concentration | Measured in fasting plasma sample by spectrophotometric assay | Day 0, Day 7, Day 14 | 
| Fasting serum insulin concentration | Measured in fasting serum sample by ELISA | Day 0, Day 7, Day 14 | 
| Fasting plasma lipid profile (for example total and HDL cholesterol and TAG concentrations; all measured in mmol/L) | Measured in fasting plasma sample by spectrophotometric assay | Day 0, Day 7, Day 14 | 
| Indirect calorimetry | Measured from expired gas samples | Day 0, Day 7, Day 14 | 
| Subjective appetite ratings | Measured from visual analogue scale appetite questionnaires | Day 0, Day 7, Day 14 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High-fat diets, High-carbohydrate diets, Glycaemic control