A blood cholesterol screening measures three types of lipids in your bloodstream: low-density lipoprotein cholesterol, high-density lipoprotein and triglycerides. Low-density lipoprotein, also known as LDL or "bad" cholesterol, and triglycerides may clog your arteries and increase your risk of heart disease. HDL, or "good" cholesterol, protects you against strokes and heart attacks by pulling LDL cholesterol and triglycerides out of your bloodstream. For accurate results, you should fast for about 12 hours before taking a cholesterol test.
Healthy Triglyceride Levels
After fasting, your triglycerides should measure 150 mg/dl -- milligrams per deciliter of blood -- or less. Ideally, your triglycerides will measure below 100 mg/dl, according to a scientific statement released in April 2011 by the American Heart Association. Triglyceride levels above 200 mg/dl put you at high risk for heart attack and levels above 500 mg/dl put you at very high risk. Your risk increases if you also suffer from diabetes or high blood pressure, if you're overweight or older than 50, if you stay physically inactive, if you smoke or if you drink more than a moderate amount of alcohol.
Eating and Fasting
Your triglyceride levels rise quickly and, sometimes, dramatically after you eat. If you fail to follow the fasting guidelines before getting your triglycerides tested, you may find the results alarming. This may prove especially true if your meal included saturated fat, trans fat, sugar and alcohol. Saturated fat, found in animal products and tropical oils, and trans fat, found in margarine and shortening, naturally contain triglycerides. If your meal included a hamburger and fries, your triglyceride levels would rise. Your body also converts sugar and alcohol to triglycerides. If you ate sweets or drank alcohol during the 12-hour fasting period, your triglycerides may test abnormally high. Large amounts of alcohol may take longer than 12 hours to leave your system.
Extended Fasts and Triglycerides
If you fast for longer than 12 hours -- to lose weight or observe a religious tradition, for instance -- your triglycerides may test abnormally low. When you don't take in enough calories, your body searches its fat stores for energy. The fat in your body makes a home for triglycerides so, when you lose weight, you lose triglycerides. If you lose weight and keep it off -- ideally through a moderate, reduced-calorie eating plan -- your triglycerides will decrease and stay low. Fasting will temporarily lower your triglycerides but, if you return to your normal eating habits, your triglycerides will also return to their pre-fasting levels.
Considerations
To get an accurate triglyceride reading, fast for the prescribed 12 hours. Fasting for a longer period may improve your score but won't improve your heart health. To protect against cardiovascular disease, regularly follow a low-fat, low-sugar diet and get plenty of exercise. You can lower your triglycerides by 50 percent through diet and exercise, according to the American Heart Association. The AHA plan to reduce triglycerides includes 16 g of saturated fat, 2 g of trans fat, 50 g to 100 g of fructose, 100 to 150 calories from foods with added sugar, no more than two alcoholic drinks a day and at least 150 minutes weekly of moderate exercise.
