The dark side of insulin

For those of us who depend on insulin to literally keep us alive, we often observe that it has another side to its nature, one that can harm us if we’re not careful. We all learn, early in our insulin dosing career, that the biggest drawback to insulin is when we take too much and it drives us hypo. That’s the more obvious negative consequence of using insulin but that is not the dark side that I’m writing about.

When I first started dosing insulin, I found that my meal doses and high-glucose corrections performed well. This encouraged me to lean into the power of insulin and deliberately slightly overdose to keep good control and also allow me the food treats that I was used to eating before my diagnosis.

While I had to keep my guard up watching for overcorrections and hypos, this system seemed to work for me. Over time, my total daily dose of insulin gradually ramped up. While my A1c remained in the mid-6% range I started gaining 1-2 pounds each year. A daily bicycle habit permitted me to eat all kinds of treats and then burn them off with a 1-2 hour aggressive cycling workout.

When my exercise habit waned, I started to notice that my high-BG corrections did not work as well, so I adjusted my correction factor (aka ISF) to permit more aggressive doses. I ended up 30 pounds overweight and my insulin correction doses often acted like I was injecting water.

They just didn’t work – until they did when I resorted to rage blousing that often meant a screaming white-knuckle descent into severe hypoglycemia (< 54 mg/dL or 3.0 mmol/L).

All those problems led me to learn some important lessons about using insulin. I learned that injecting more insulin than is needed, especially over enough time, causes insulin resistance. When I changed my way of eating and strictly limited carb consumption, my total daily insulin doses were cut to less than half of what I had been taking. I lost about 14% (25 pounds) of my body weight and my glucose corrections started acting rationally again.

Fast forward to today when I’m using an automated insulin dosing system comprised of a pump, CGM, and an algorithm stored on my phone. I recently updated the algorithm to one that instead of setting temporary basal rates to control glucose levels, it delivered small “microbuses” to maintain control.

Over a week’s time, however, I was alarmed to see that my total daily dose of insulin ramped up by 25% while my control degraded. My past experience informed me that this was not a good thing.

I know that this auto-bolus tactic works well for many so I’m sure that my settings were not optimal. But I wasn’t comfortable infusing so much insulin, so for the time being I changed back to my modulated temporary basal rate algorithm.

Yesterday, I decided to do a 36-hour fast to help bring my metabolism back into a decent balance. It seems that my sensitivity to insulin has returned to more usual levels. Fasting is a potent tactic with few downsides.

Insulin, like any powerful tool, has a bad side as well as a good one. If you abuse its power, it has shown me that its potency can evaporate. I don’t want to live without an effective, potent and rational-acting insulin in my kit.


@Terry4, you have just described exactly what I am experiencing with my Tandem x2 with CIQ and 24-hour Sleep Mode. Micro-bolusing is what the Tandem does. No getting away from it. And I am in a constant battle with the CIQ, which has a non-resetable target of 112 for the Sleep Mode. I have gained approximately 15 pounds and an extra 5 units of TDD since I started using CIQ two years ago. I love the fact that I no longer gets middle-of-the-night hypos. However, the rest of the day is up for grabs. And I have often “rage bolused” and ended up on the rollercoaster. Unless Tandem comes out with an update that brings the target BG down, I am seriously considering turning off CIQ and using the x2 as a “dumb pump.”


“Over a week’s time, however, I was alarmed to see that my total daily dose of insulin ramped up by 25% while my control degraded. My past experience informed me that this was not a good thing.”
“Yesterday, I decided to do a 36-hour fast to help bring my metabolism back into a decent balance. It seems that my sensitivity to insulin has returned to more usual levels. Fasting is a potent tactic with few downsides.”

What always amazes me is how fast the body adjusts to any amount of insulin or food we throw into it which is a godsend when we work hard at tweaking our regiments to achieve acceptable diabetic control.


I’m with you on this. When I first started my tandem I went from averaging 50 units a day to 60. But after my sugars leveled out more, I’m back to 50.
I never really noticed insulin resistance before, but now I see it clearly, when I eat fatty foods, it requires 2-3x the insulin.

Also when my sugar is high, I become more resistant to insulin.

Staying in range keeps my insulin needs lower. And exercise reduces it even more. I mean just casual exercise.

I walk before or after each meal, and it helps a lot. Maintain a healthy sugar level.

I also realized after reading Mastering diabetes, that I had a misunderstanding about how insulin and carbs and fat and insulin resistance all work together.

I have reduced my fat intake and it has helped a lot. I don’t follow the mastering diabetes diet closely, but even as much as I do, I see benefits, and I can have more healthy carbs this way.

I have also worked in intermittent fasting. Like you said it can reset your metabolism.

I try to eat 2 meals a day and on Sundays I only eat one meal in the evening. If my sugar tanks , I eat something small but it usually doesn’t.

So different from what I was originally taught, eating low carb and making sure I ate all the time to prevent lows and prevent being hungry.
Mixing fat with carbs to slow the absorption. That one was the worst idea ever because it throws me off for 12 hours.

I tried cholestoff for a while and it was really good and dropping my cholesterol, but I got scared off of side effects.

Now that I have reduced oil and fat, my cholesterol and LDL are normal, my HDL is pretty high because I’m active, and hasn’t changed. Runs around 70. My cholesterol now 180. Not great but I’m hoping it will settle down more.
Historically have run in the 120s for cholesterol. It was just genetics. My mother also had a similar situation where her cholesterol jumped up in her 50s too. I can’t tolerate statins, or I would take them.

The all time best things we can do for ourselves it to listen to what our other friends have tried, try some of those things and come up with what works for us.

I’m 55, t1 for 34 years. I want to make it to 90 with my kidneys and eyes and toes in tact. I never thought I could, but now with all the advancements and deeper understanding, I think it’s possible.


I don’t think I mind the target range of 112-120 as much as I mind that I lose 80-112 as acceptable numbers. I have adjusted my settings more times than I can count, but when Control IQ reduces or suspends my insulin, I almost always end up with stubborn highs later.

I don’t think that I am using more insulin with Control IQ so I guess that is good. I just find that Control IQ frustrates me as much as it helps me.

Lately I turn off Control IQ most of the time but use it when I am doing things like hiking where it helps me prevent lows. Or if I wake up during the night and am trending high, I’ll turn on Control IQ to help ameliorate that.

I have tried lots of regimens and different insulins in recent months. I mostly do okay but haven’t found a magic bullet that works every minute of every hour of every day. Nothing that makes my diabetes easier.

But I think that for the average person, Control IQ improves things greatly. But not for those of us already doing well who want to do better or have D-life be easier.

Fortunately Control IQ is easy to turn on and off and I do it regularly.


Shortly after starting CIQ, I just wanted to see it do its thing and accepted the A1C that resulted. I’m not sure if it is me, but on CIQ my average blood sugar has gone up but my a1c remains in the 5s.

As hard as it was. I stopped chasing the dragon and just let it CIQ do its thing. What resulted was more level BSs and less spikes up and down.

So I’m not convinced the CIQ algorithm (target 112) needs to be changed. I also run in sleep mode 24/7.


This is not desirable to me but we must remember that people who take insulin have traditionally almost always gained weight over time. I don’t, however, accept that we must accept that fate. We need to try to mitigate that fact about using insulin and try to find things that will help us maintain our control without attendant weight gain. It can be done!

@Willow4, perhaps you should experiment with turning off CIQ and see what you can learn. I don’t think micro-bolusing in and of itself is any less or more desirable as an algorithm. In my case, I am attributing my TDD increase as dosing inexperience. I will experiment more as time goes on after I can stabilize my control and return to my former TDD.

I do think that the human body and its strong bias towards homeostasis makes it remarkable. Since we’re dealing with a broken glucose metabolism, we don’t benefit from that aspect of homeostasis.

Low fat, high carbs is definitely another way to eat and still control BGs, @Timothy. Do you find it difficult to resist eating fats? I agree that exercise everyday help control BGs and keep you sensitive to insulin’s action. I’d like to make it to 90 with all my body parts intact as well! But I want my health span to be as long as my life span.

I agree with that. I find interesting your observation that for the average person, CIQ is a benefit but for those who target and are used to better control, they need to make adjustments and play with the system.

I wonder if any of the algorithm designers would ever consider loosening the controls for people who demonstrate an ability to manage well their glucose variability as measured by standard deviation and coefficient of variation. Unfortunately, I’ve never seen anyone mention this beyond me. I won’t hold my breathe and it looks like I’ll be using the DIY system for a few years longer.

That looks like a winner for you, Jim.

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I currently enjoy my time with DIY Loop. I believe these will be the golden years of blood sugar control. I wouldn’t be surprised if in my lifetime the FDA will not approve anything as good as that. I was hoping that DIY Loop would improve my BG control. This has not happened. I always walk the line and offset any advances in tools by eating more ‘normal’. For me it is a big relief that I don’t have to calibrate my Dex anymore. I also don’t get alarms during the night anymore. I go hours without checking my BG. I know that DIY Loop will do a good enough job. For many years I have stabilized at average BG 95 mg/dL, STD 25 mg/dL and 80% or better below 120 mg/dL. I am getting tired of wanting to improve. The biggest obstacle to any improvement is the inherent unpredictability. For the most part all my days are the same. I get up at the same time, I eat the same thing, I exercise the same amount. But my BG is totally unpredictable. @Terry4 points out insulin sensitivity is a major source. It always surprised that insulin sensitivity is considered constant by the average medical professional. My insulin sensitivity if very unpredictable on day 1 and day 3 with the OmniPod. Only day 2 typically is worry free. The effects of consuming lots of carbs and lack of exercise I experience during beach vacations. After about 3 days my insulin requirement goes up threefold. I am also getting back to normal in 3 days. I excepted that I had to eat low carb when I was diagnosed almost 50 years ago. I did very well until I got Humalog. All of a sudden I thought high blood sugar is more acceptable because I can bring it down faster. I am getting more and more convinced that it was evil to tell diabetics that they can eat as many carbs as they want as long as they compensate with insulin appropriately. I believe that too much insulin is really bad. I got away with walking the line for too long. I don’t expect that I will change my behavior unless my insulin requirement goes up. A possible motivation would be an insulin sensitivity report. Clarity reports act as my conscience. If I don’t see my goal STD and TIR, I reign it in. If this report had an insulin sensitivity number, I would definitely keep an eye on that too.


One reason better control leads to weight gain is we are no longer peeing out all that sugar. Sadly, the easiest way to lose weight is to run high.


Works that way for me, too. I review my data every day. Some people may consider this a nuisance but for me, viewing the numbers holds me accountable.

My glucose control, like my glucose trace itself, runs in waves. If it’s trending away from my expectations then I make some concrete changes like better attention to pre-bolus times or missing a meal to settle down glucose variability.

Your glucose control is excellent, Helmut. I agree that the medical professional philosophy of “carb-up, shoot-up” was a failure in my book. I know they felt they were so enlightened easing up on the rigid lifestyle of a previous generation who used fixed N and R doses and eating to the dose, but they went overboard.

The problem is, no one, not even gluco-normals should eat highly processed and highly palatable foods with a long list of unpronounceable ingredients. Beyond the current Covid-19 pandemic, we are in an even more serious diabetes pandemic.

@MBW – yeah, you can lose weight by running high, like consistently over 180 (10.0). But you can lose significant weight without that dangerous method. I’ve done it and successfully kept the weight off. I believe that good BG control without weight gain is possible if people will commit to a change of eating style. People don’t often like to entertain that reality, however.


@Terry4 i am not in any way advocating hyperglycaemia as a healthy way to lose weight! Just that if we make no other changes in our life, better glucose control through insulin is inevitable to result in weight gain. Eating healthy foods in healthy amounts, staying active, and maintaining euglycemia is the key to health for us.


Terry, what you write reminds me a little of the epilogue that Bliss wrote for The Discovery Of Insulin. It is recommended reading. Bliss wasn’t an insulin user himself so he didn’t have the emotional ups and downs that us real diabetics do but he did come to similar worries.

I think all of us go through ups and downs in dealing with our need for insulin. Just hitting three other major phases I’ve gone through multiple times myself:

1: Boy insulin is great I would’ve been dead for the past 40 years without it.

  1. Geeze I’m sick of this insulin crap I’m not sure I’ll be able to fill my prescription because I don’t have the money or I can’t work up the energy to actually go take it.

  2. Oh no I can’t afford my insulin I better cut back on my doses and ration it.

  3. A place I myself haven’t gone but I’ve helped out in support groups where some folks had gone through it: Diabulimia . I don’t think you are there either but mixing where you are with my points 2 and 3 it’s very easy to see the slippery slope to where an intelligent and sensitive person might end up cutting doses to lose weight in an unhealthy way.


I don’t go all in on the low fat high carb diet. I only cooled down my fat intake.
I stopped eating oil and I cut down a lot on animal protein.
I don’t find it difficult because I don’t go overboard.

I miss peanut butter and bacon. Other than that I’m golden.
I mean bacon is not really something I ever thought was healthy.

I think we all need to eat less as we age. That goes for all people not just diabetics because we move less.

When I look at young people going about their days I can see how much more energy they use doing ordinary things.

I know that even though I keep active, it’s no where near the intensity I had even 10 years ago.
And yes the lower I brought my a1c the more weight I’ve gained.
I’m normal weight, but I’ve been very lean most of my life so it seems weird to me to carry any excess fat.
I think it’s mostly genetics, add that to the fact that I don’t eat a lot of the foods that make most people overweight like candy cake chips.
I love pie though. Esp banana cream pie. I will break all the rules for banana cream pie or coconut cream pie. Yum


I refer to insulin as the fat hormone. It tells the body to put on some weight. I totally agree that alternate measures to reduce BG, like exercise or eating less carbs are way better means to improve BG control.


Insulin is a beautiful, wonderful and powerful substance. It works so well it is fantastic. But like all tools, we must be careful using it. A substance so powerful it will destroy us if we are not careful.


I am not on a pump, I have been a type 1 since I was 8 and I will be 71 next month. Recently 2 physicians in different offices have told me that I am the healthiest looking diabetic they have ever seen.

I really work very hard at this as all of us here do. I am now 5ft tall and weigh 105. I would rather weigh 100. I started taking nortriptylene for statin induced neuropathy, and it is causing weight gain. I will probably try to stop taking it. I hate gaining weight.

I eat a mostly vegan diet with lots of fruit, vegetables and grains. About 10% of my diet is from fat mostly from nuts and seeds. I usually take a total of 22 units of insulin. I eat almost 10 times the amount of carbs as when I was low carbing and I take almost the same amount of insulin. I rarely miss fat. I alway eat a lot of fruit and oatmeal for breakfast and quinoa, beans, and vegies for lunch. My dinner varies. I never skip meals.

For over 2 weeks a month, my diabetes is pretty easy. I stay in range without much effort. Oh, exercise is a big part of my life too. I don’t like to take much insulin so I exercise instead.

This week I forgot my Tresiba shot in the morning and that didn’t help control at all. I finally realized it when my glucose level went up over 140 and exercise wouldn’t bring it down. I ended up going up higher before my Novolog brought it down. My hardest day is when I put on a new sensor. Even though I do soak it, the new sensor is usually wrong for the first 24 hrs. The one I am wearing now has been a problem, although my last one was great.

Usually I can figure out why my glucose level rises or decreases, but not always, and then I become somewhat frustrated.
I am trying to live another 10-15 yrs if possible. It is very hard work. Life was much easier when I ate whatever I wanted and really didn’t think about my diabetes all that much, but that wasn’t a healthy way for me to live.

I would rather not have to remember to take all of these shots, but I don’t think I would be happy on a pump. My last A1c was 4.8 or 4.9 but I don’t expect it to be that low this time. My biggest problem is that I drop into the 50’s too often during the day. I should lower my insulin but I don’t want to deal with highs.


Marilyn, I think that you’ve tweaked your diabetes interventions well with regard to using all the insulin you need and not a drop more. Clinicians sometimes use the rule-of-thumb when starting someone on injected insulin to start on 0.5 units of insulin per kilogram of body weight. That formula predicts your nominal insulin need of about 24 units per day; you are using 2 fewer units than that.

You live with an A1c that compares well with a metabolically healthy gluco-normal.

With all the possible challenges of taking external insulin, you have reduced your risk into the least dangerous. Besides, I expect your glucose variability as measured by standard deviation or coefficient of variation is low and protects you.

Dealing with hypos when variability is low is a much more manageable task then when BGs are swinging wildly. I think you have made a rational trade-off. It would make many doctors nervous but those practitioners don’t often consider mild glucose variability and the power it has to mitigate hypo danger. I don’t think you need worry much about the dark side of insulin I described.


I think the main difference between the amount of insulin I take and what others take is that I eat about 275 carbs daily while taking 22 units of insulin. Lowering fat content really drops insulin resistance a huge amount.


What’s the difference between temporary basal rates and microboluses?

If you use a pump independently of an algorithm, you may manually set a temporary basal rate. These are often set for a 30-minute duration and they replace the pump-programmed basal profile. These temp basal can be below, above or equal to the programmed basal profile.

Automated insulin dosing systems like DIY Loop can set temporary basal rates automatically, as often as every five minutes, to affect a glucose level that is straying above or below the user-defined target range.

When micro-boluses are used, the algorithm looks at the current glucose level and can add a small bolus, like 0.2 units, as often as every five minutes. The micro-bolus tactic is used primarily to replace the temp-basal strategy.

Both tactics can work. The user needs to make adjustment to customize to their unique metabolism. And as with all things diabetes, when a solution is found, needs will change and you must adjust or get left behind scratching your head.