Impaired glucose tolerance is associated with genetic defects, obesity, and insulin resistance. If a blood glucose test shows a fasting blood glucose of 6.1 to 7.0 mmol/L and a 2-hour postprandial blood glucose of 7.8 to 11.1 mmol/L, it is called impaired glucose tolerance. Impaired glucose tolerance is a pre-diabetic condition, i.e. a state between diabetes and a healthy state. There is a relationship between impaired glucose tolerance and genetic defects, which are not caused by a single gene, but by a combination of several genes that are defective. Exactly which genes are involved is unclear. There is also a relationship between impaired glucose tolerance and obesity. Some studies have shown that there is a direct correlation between obesity and overweight and impaired glucose tolerance, possibly related to the fact that increased cellular fat leads to insulin resistance. Finally, the direct cause of impaired glucose tolerance is decreased insulin sensitivity. The so-called insulin sensitivity decline, the body’s response to insulin is not sensitive, so that insulin can not properly play the role of hypoglycemia, resulting in the blood glucose is not able to be transferred to the tissue cells in a timely manner, which produces an increase in blood glucose. Once impaired glucose tolerance is found, intervention and regulation should be carried out under the guidance of a doctor, and should not be left unattended.