Fat Metabolism in Response to Acute Diet- and Exercise-induced Changes in Energy Balance

Study Overview
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Brief Summary
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This study is being conducted to learn more about the role of diet and exercise in regulating plasma triglyceride (fat) metabolism. The investigators will examine the effect of acute (24 hour) changes in energy intake and expenditure on fat metabolism the following day.

Detailed Description
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Excess body fat and a sedentary lifestyle are associated with increased plasma triglyceride (TG) and apolipoprotein B-100 (apoB-100) concentrations, which are important risk factors for the development of cardiovascular disease. Weight loss and endurance exercise improve plasma lipid and lipoprotein concentrations. However, the mechanisms responsible for this effect are largely unknown, and much uncertainty remains regarding the independent roles of dietary energy intake, exercise energy expenditure, and net energy balance in controlling plasma TG concentrations. The main goal of this project, therefore, is to investigate the mechanisms by which acute alterations in energy balance, induced by diet and/or physical activity (endurance exercise), regulate very-low density lipoprotein (VLDL) metabolism. Subjects will be asked to perform 3 separate trials. One of these will always be an energy balance trial that will act as the control trial for the other 2 trials they perform. Subjects will therefore be randomized to 2 different study arms.

Official Title
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VLDL-triglyceride Metabolism in Response to Acute Diet- and Exercise-induced Changes in Energy Balance

Conditions
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Cardiovascular Diseases

Intervention / Treatment
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* Behavioral: Positive energy balance
* Behavioral: Energy balance with exercise
* Behavioral: Negative energy balance
* Behavioral: Negative energy balance with exercise
* Behavioral: Energy balance


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: overweight and obese men normal to mild hypertriglyceridemia Exclusion Criteria: Smoking Any medical condition other than increased body weight (e.g. diabetes, heart disease, etc.). Use of drugs known to affect lipid metabolism (e.g. statins, etc.). Regular exercise training.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Male

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: Prevention
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Positive energy balance<br>Comparison between isocaloric and hypercaloric diets with no exercise performed in any trials | Behavioral: Positive energy balance<br>* Subjects will consume over a 24 hour period 33% more calories than they require to meet their energy demands.<br>Behavioral: Energy balance<br>* Subjects will consume over a 24 hour period a sufficient amount of calories to meet their energy needs.<br>|
| Experimental: Energy balance with exercise<br>Comparison between an isocaloric diet without exercise and a hypercaloric diet with a sufficient amount of exercise performed to match the excess calories consumed resulting in both trials being in net energy balance. | Behavioral: Energy balance with exercise<br>* Subjects will consume over a 24 hour period 33% more calories than they require to meet their energy demands but will perform 2 hours of exercise that will be sufficient to burn off the excess calories consumed resulting in subjects being in net energy balance.<br>Behavioral: Energy balance<br>* Subjects will consume over a 24 hour period a sufficient amount of calories to meet their energy needs.<br>|
| Experimental: Negative energy balance<br>Comparison between isocaloric and hypocaloric diets with no exercise performed in any trials | Behavioral: Negative energy balance<br>* Subjects will consume over a 24 h period only 66% of the calories required to meet their energy demands such that they will be in a net negative calorie balance in this trial.<br>Behavioral: Energy balance<br>* Subjects will consume over a 24 hour period a sufficient amount of calories to meet their energy needs.<br>|
| Experimental: Negative energy balance with exercise<br>Comparison between consuming an isocaloric diet without exercise and consuming the same amount of calories as in the isocaloric trial but with exercise performed resulting in net negative energy balance in the exercise trial. | Behavioral: Negative energy balance with exercise<br>* Subjects will consume over a 24 hour period the same amount of calories as ingested in the isocaloric trial but will also perform 2 hours of exercise that will be sufficient to burn off a third of the calories they consumed during this day resulting in subjects being in net negative energy balance in this trial<br>Behavioral: Energy balance<br>* Subjects will consume over a 24 hour period a sufficient amount of calories to meet their energy needs.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Very Low Density Lipoprotein-Triglyceride and apoB-100 concentrations |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Liver Very Low Density Lipoprotein-Triglyceride and apoB-100 secretion rates |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 
| Liver Very Low Density Lipoprotein-Triglyceride and apoB-100 clearance rates from plasma |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma glucose concentration and turnover rate |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma insulin concentration |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma free fatty acid concentration and turnover rate |  | After acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma glucose concentration | Measured hourly over the 24 h period. | During acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma insulin concentration | Measured hourly over the 24 h period. | During acute (24 hour) changes in energy intake and/or energy expenditure | 
| Plasma free fatty acid concentration | Measured hourly over the 24 h period. | During acute (24 hour) changes in energy intake and/or energy expenditure | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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fat metabolism, exercise, liver, lipoproteins, triglycerides