Can you eat before checking your blood sugar?
Sep 08, 2022
Source: Cainiu Health
Dr. Pan Yongyuan
Introduction
If the patient is measuring postprandial blood glucose, they can usually eat, with the timing starting from the first bite of the meal. Blood glucose should then be measured two hours after the meal. If measuring fasting blood glucose, the patient should not eat anything. This is because the ideal condition for monitoring fasting blood glucose is after at least 10 hours of fasting, which typically yields more accurate results and reflects the basal secretion function of pancreatic beta cells.
Blood glucose testing: If testing postprandial (after-meal) blood glucose, you may eat. However, if testing fasting blood glucose, you typically should not eat.
1. Eating is allowed
If a patient is measuring postprandial blood glucose, eating is generally permitted and the person should not be fasting. The timing starts from the first bite of food, and blood glucose measurement should begin exactly two hours after that. If the patient is taking glucose-lowering medications, they should continue to eat as usual and take their medication normally when testing. The normal range for blood glucose two hours after a meal is typically below 7.8 mmol/L.
2. Eating is not allowed
If testing fasting blood glucose, eating is generally not permitted. The ideal condition for measuring fasting blood glucose is after at least 10 hours of fasting with no food intake. Therefore, patients are usually advised not to eat anything after dinner the previous evening. This ensures more accurate results, which reflect the basal insulin secretion function of pancreatic β-cells. Fasting blood glucose is one of the most commonly used indicators in diabetes screening. The normal reference range for fasting blood glucose is between 3.9 and 6.1 mmol/L.
