Your blood naturally contains a certain amount of lipids, including different forms of cholesterol and triglycerides. If your doctor wants to measure your triglyceride levels, he may ask you to not eat for several hours before the test, as your triglyceride levels are influenced by what you eat and when you last ate, which can make the test inaccurate.
Triglycerides and Food
Lipids are the chemical form of fat in the body. Triglycerides are lipids that are generally found in fat. When you eat a meal with fat, your digestive tract breaks it down and converts it to triglycerides, which are then released into your bloodstream. Your body uses some of these triglycerides for energy, but the rest are stored as fat. Your body can also convert excess calories from other sources, such as carbohydrates, into triglycerides. Thus, when you eat foods with fat in them, your triglyceride levels go up.
Fasting Triglycerides
Because food can lead to an increase in triglyceride levels, many doctors have patients fast for nine to 12 hours before they have blood drawn. Fasting triglyceride levels are used as a baseline in a lipid panel.
Day-Long Fasts and Triglyceride Levels
Some evidence suggests that periodically going without food for a day can be a way to control triglyceride levels. Dr. Benjamin Horne of the Intermountain Medical Center Heart Institute in Murray, Utah, examined the effects of fasting for 24 hours on triglyceride levels and overall risk factors for heart disease. His results suggested that fasting could help keep triglyceride levels low, according to a 2009 article in "Discover" magazine. To date, however, Dr. Horne is the only researcher who has examined the effects of periodic fasting on blood triglyceride levels.
Importance of Triglycerides
Triglycerides are important because they represent a reserve source of fuel that can be used when your blood-glucose levels are low. Very high triglycerides, on the other hand, can increase your risk of developing cardiovascular problems such as atherosclerosis. If you have high triglyceride levels, taking steps to reduce them, either by periodic fasting or by changing your diet, can lower your chances of having a heart attack or stroke.
