In normal people, insulin secretion increases after eating and peaks within 30 to 60 minutes. In people with pre-diabetes or diabetes, the time period of secretion will be different. Insulin is secreted 24 hours a day and increases after eating calorie-rich foods. In normal people, insulin secretion peaks in 30 to 60 minutes and is about 5 to 10 times that of fasting basal insulin. People with impaired glucose tolerance, such as pre-diabetic and diabetic patients, the time period of insulin secretion will be different from that of normal people, and OGTT and other related tests can be performed to clarify the diagnosis. Abnormal insulin secretion is recommended to consult a doctor for timely treatment.