How long it takes to eat after taking insulin is usually related to the type of insulin, and it is recommended to consult your doctor. 1. Rapid-acting insulin: The common rapid-acting insulin analog is Mentholatum insulin, which has an onset of action in about 10 minutes, and can be used to eat immediately after taking insulin, so as to avoid hypoglycemia caused by failure to eat in time after taking insulin. 2. Premixed insulin: Premixed insulin is composed of a certain proportion of short-acting and long-acting insulin, and common premixed insulin analogs are Mentholatum 30 injection and Mentholatum 50 injection, which can be injected immediately before meals or after meals. Different types of insulin are injected at different times after meals, and insulin should be applied reasonably under the guidance of a doctor.