Some people quickly come to associate taking insulin with weight gain. They will sometimes cut back on their insulin and let their blood glucose run high once they discover they can lose a few pounds in a few days times by doing so. Unfortunately, when they go back to using the right amount of insulin to maintain good control, they are dismayed to discover that they gain the weight back — and perhaps more — in equally rapid fashion. Manipulating insulin to lose weight is an unhealthy pattern to get into. Letting your blood glucose run high can lead to long-term complications — and up and down weight problems when you try to bring your blood glucose back to a normal range.