NPH Insulin and Food
Insulin and food are an issue of balance. Kind of like a race... A relay race really, because there is constant processing of the food and the insulin throughout the period of time between meals and injections. The finish line is the bloodstream. Sometimes the food team is ahead, sometimes the insulin. We defined “good regulation” of diabetes as the best blood sugar levels you can achieve safely. That is, with little risk of low blood sugar (hypoglycemia, which occurs at less than 75 mg/dL). With injections you are seeking to replace a very sensitive body system that adjusts the amount of insulin available moment by moment with an artificial system that provides a few injections of insulin a day and meals that deliver sugar into the bloodstream as they are digested.
If the insulin gets ahead of the food being digested and turned into glucose, your blood sugar can drop too far too fast. If the food gets ahead of the insulin, your blood sugar can rise too far too fast. A dead heat is what you want - food and insulin being delivered in balance, giving you a steady supply of glucose in a good range throughout the day.
The NPH insulin family is a genetically-engineered version of the human insulin molecule. It is an intermediate acting insulin that uses protamine, a protein from fish, to delay the absorption of the insulin so that one injection can have a measured effect on blood glucose over 8–12 hours. NPH is generally given twice a day - an injection with a meal every 12 hours - and provides control of the blood sugar level for about 8–14 hours.
Limiting simple sugars and carbohydrates is an important part of matching the digestion of food with the absorption of injected insulin. Foods that are digested too quickly, as simple sugars and carbohydrates are, generally cannot be matched to absorption of the insulin, even with faster acting insulin. The glucose from these foods speeds into the bloodstream far faster than the insulin can get there. And the result is that you will have very high blood sugar a few hours after eating - because the insulin hasn’t caught up - and then could have dangerously low blood sugar six or seven hours later when the food is exhausted and the insulin is getting its second wind and sprinting for the bloodstream.
For many years, a high fiber diet has been the mainstay of prescriptions for diabetics. Most prescription diets for diabetics are high in fiber and low in fat. In recent years that approach has been relaxed and people are finding that there are many diets that can balance the insulin’s action to give good blood glucose control throughout the day.