Some people fast to lose weight or remove toxins from their body, while others fast for religious purposes. You may be asked to fast before going to the doctor for a check-up. Blood tests that check cholesterol and triglyceride levels, require fasting to obtain accurate results. Because triglycerides, a type of fat in your blood, increase after eating, you should fast for 8 to 12 hours prior to testing. Fasting does not raise triglyceride levels; it provides a way to determine the true level.
Triglycerides
Fats in triglyceride form contain a glycerol molecule with three fatty acids attached. The fat in vegetable oils and animal fats exist in triglyceride form. Eating these foods raises your triglyceride levels. Maintaining a low and healthy triglyceride level requires more than just fasting, or abstaining, from eating fat because your body converts any unused calories into triglycerides.
Effects
High triglycerides levels increase your risk for heart disease, the leading cause of death for men and women in the United States. The exact mechanism of action for how triglycerides affect your heart and blood vessels remains a mystery, but doctors theorize that triglycerides contribute to the process of atherosclerosis. Atherosclerosis is the accumulation of plaque – a substance consisting of fat, cholesterol, minerals and other waste material – along the walls of the blood vessels. As plaque builds up, the arteries become thick and hard, which inhibits the flow of blood to the heart.
Testing
To monitor your heart disease risk, doctors perform a lipid panel blood test. The lipid panel provides results for total cholesterol levels, low-density cholesterol, high-density cholesterol and triglycerides. To maintain a healthy cardiovascular system and a low risk for heart disease keep your triglyceride levels to 150 milligrams per deciliter or less. The American Heart Association established an optimal triglyceride level of 100 milligrams per deciliter in 2011. Triglyceride readings between 150 and 199 milligrams per deciliter borderline on high and doctors diagnose any level over 200 milligrams per deciliter as high triglycerides. To ensure accurate test results doctors suggest you fast before providing blood for a lipid panel test.
Fasting
Because your body converts excess calories into triglycerides, your triglyceride levels increase after eating and fasting actually lowers your triglyceride levels. To lower your triglyceride levels, the American Heart Association recommends eating fewer calories, limiting your fat intake to no more than 25 to 35 percent of your total calories, and limiting your intake of added sugars in foods like syrups and colas.
References
- MedlinePlus: Triglyceride Levels; May 2010
- Cleveland Clinic: What you Need to Know About Triglycerides
- University of Maryland Medical Center: All About Triglycerides; Dr. Michael Miller; April 2011
- Theheart.org: Diet and Exercise Key for Treating High Triglycerides – New AHA Statement; M. O’Riordan; April 2011
