My experience with the amount of insulin I take taught me a few things about my health. For many years I took about 40-50 units total daily dose. Then I started a slow but steady march toward a higher body weight. I moved from 150 pounds up to a high of 183 pounds over a 10 year period.
When I received a gastroparesis diagnosis in 2012, that energized my motivation. My blood sugar control had deteriorated and my A1c slipped from the mid 6% range to 8.3%. At that point I was taking about 80 units per day.
I jumped into a carb-limited diet focussed on regaining blood sugar control. I was amazed that my excess body weight started to fall off without much exercise of willpower. My total daily dose of insulin fell to about 40 units.
From this personal experience, I believe that high insulin dosages lead to insulin resistance and metabolic dysfunction. When I was taking 80 units per day my time in range was low and the amount of time I spent hyper and hypo was high. My glucose variability as measured by standard deviation was high. I remember my SD was 60 mg/dL and higher.
I believe that a T1D who uses too much insulin creates metabolic syndrome and insulin resistance much like many T2Ds.
Finally, for those who would like to lose some weight, I’ve read that the body cannot access fat stores when insulin is too high. When I adopted a carb-limited diet, my daily insulin intake was cut by half, I lost weight and my glucose control improved by every measure.
I don’t think there is one magic number total daily insulin dose for everyone, even if you use a weight-based adjustment. I’ve read that doctors use 0.5 units of insulin per kilogram of body weight as a TDD starting point for a new T1D.
I do, however, think that there exists a pivot point for each of us and when we start to take more insulin than that, insidious metabolic things start to happen. It’s our individual job to identify that pivot point and take action when we exceed it.