Cardiovascular Diseases
Conditions
Keywords
fat metabolism, exercise, liver, lipoproteins, triglycerides
Brief summary
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
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.
Interventions
BEHAVIORALPositive energy balance
Subjects will consume over a 24 hour period 33% more calories than they require to meet their energy demands.
BEHAVIORALEnergy balance with exercise
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.
BEHAVIORALNegative energy balance
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.
BEHAVIORALNegative energy balance with exercise
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
BEHAVIORALEnergy balance
Subjects will consume over a 24 hour period a sufficient amount of calories to meet their energy needs.
Sponsors
Washington University School of Medicine
Study design
Allocation
RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
MALE
Age
21 Years to 50 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Very Low Density Lipoprotein-Triglyceride and apoB-100 concentrations | After acute (24 hour) changes in energy intake and/or energy expenditure |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| 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 | — |
| Liver Very Low Density Lipoprotein-Triglyceride and apoB-100 secretion rates | After acute (24 hour) changes in energy intake and/or energy expenditure | — |
| Plasma glucose concentration | During acute (24 hour) changes in energy intake and/or energy expenditure | Measured hourly over the 24 h period. |
| Plasma free fatty acid concentration | During acute (24 hour) changes in energy intake and/or energy expenditure | Measured hourly over the 24 h period. |
| Plasma free fatty acid concentration and turnover rate | After acute (24 hour) changes in energy intake and/or energy expenditure | — |
Countries
United States
Outcome results
None listed