The bleeding that occurs while you take the inactive pills isn't the same as a regular period. Nor is the bleeding necessary for health. This is good news if you take birth control pills and want more control over your menstrual cycle, either for personal or medical reasons.
To prepare for the glucose tolerance diagnostic test: 1  Eat a balanced diet that contains at least 150 grams (g) of carbohydrate per day for 3 days before the test. Fruits, breads, cereals, grains, rice, crackers, and starchy vegetables such as potatoes, beans, and corn are good sources of carbohydrate.
Blood glucose tests and cholesterol tests require patients to avoid eating or drinking anything except water for 8 hours before the test, unless directed otherwise by a doctor, as stated by Geisinger Medical Laboratories. Patients can usually eat normally before other types of blood tests.