Insulin and Weight Gain
In many people taking insulin, a common side effect is weight gain. Insulin can cause people to gain weight for several reasons. For example, insulin reduces the removal of glucose (sugar) from the body, and this excess glucose is stored as fat. However, taking insulin does not automatically mean you will gain weight. If you are taking insulin and notice that you are gaining weight, you may be able to control your weight with proper diet and exercise.
Weight gain is one of the most frustrating and seemingly unfair side effects of insulin. While many people gain weight while taking insulin, there are ways to help prevent or reduce the weight gain that often comes with insulin use.
There are a few different reasons why insulin causes weight gain. Probably, the most significant reason is that insulin reduces the removal of glucose (sugar) through the urine. With uncontrolled diabetes, the body cannot use (or store) glucose properly, and glucose is lost through the urine. This means that you can consume more calories than you need, and your body cannot use it or store it as fat as well as normal. As soon as you correct the situation with insulin, all of a sudden, your body can access the glucose in the blood. Any excess glucose is not lost through the urine; it is stored as fat. In this sense, insulin is not really causing the weight gain; it is simply correcting the problem (high diabetes) that once allowed you to eat more than you needed.
Secondly, insulin can cause episodes of low blood sugar levels (hypoglycemia). Hypoglycemic episodes are very frightening. People who have experienced hypoglycemic episodes due to insulin may be more likely to overeat in order to avoid future episodes. This overeating can lead to weight gain.
Thirdly, some people feel that as long as they take insulin, they can eat whatever they want. While it is true that if you know how to appropriately adjust your dosage, insulin can be used to control blood sugar no matter what (or how much) you eat, insulin does not prevent weight gain from eating too much.
Lastly, it is thought that insulin itself may cause weight gain. It is not clear as to how or why this might occur.