Diabetes interferes with the production of insulin and use of glucose. Blood glucose levels become elevated, wreaking havoc with the other organ systems in the body. In order to diagnose diabetes or its precursor, pre-diabetes, a fasting plasma glucose test is performed, according to the National Diabetes Information Clearinghouse. The FPG measures blood glucose levels after fasting. A fasting blood glucose test requires that the person being tested not have anything to eat or drink for at least eight hours before the test, typically overnight, according to Lab Tests Online.
Grains
Those having an FPG should not eat any foods from the grain food group prior to testing. The grain food group includes foods such as whole grain breads and pastas, brown rice, steel-cut oatmeal and other cereals, muffins, bagels and grits.
Protein
All foods containing protein should not be eaten prior to having an FPG. Foods containing protein include beef, pork, lamb, poultry, fish, shrimp and lobster. Nuts and legumes, such as soybean products, beans, split peas, peanuts, peanut butter, walnuts, almonds and sunflower seeds should also be avoided before have this fasting blood test.
Dairy Products
Dairy products cannot be eaten with eight hours of having the test. These foods include all types of milk, buttermilk, cream, half-and-half, coffee creamers, cheeses and yogurt, according to the Centers for Disease Control and Prevention.
Fruits and Vegetables
Fruits and vegetables should not be eaten within eight hours of having a fasting plasma glucose test. Fruits include apples, oranges, grapefruit, bananas, grapes, blueberries, raspberries, pineapple, plums, raisins mangoes, strawberries and tangerines. Vegetables include tomatoes, potatoes, carrots, collard greens, okra, lettuce, cabbage, spinach, corn, green beans, peas, squash and sweet potatoes.
Beverages
Besides avoiding all foods from all food groups, it is also necessary to avoid all beverages as well. Those having the test cannot drink coffee, tea, lattes, milk, orange juice, all cranberry juices, apple juice, tomato juice, soda and nutritional supplements, such as Ensure.
Medications
It is possible that some people will have medications they need to take at specific times. If those times conflict with the timing of the FPG test, the physician may recommend taking that medication with a tiny amount of water prior to having the test performed. It is best to discuss when to take any medications with the physician who ordered the test.
