Intermittent fasting, a potent BG control tactic

A few weeks back I disconnected my pump for the first substantial time period in 29 years. I wanted to try the basal insulin, Tresiba. It’s worked out well but not without some challenges. I’ve had problems with two consecutive Dexcom sensors. The first was erratic and I terminated the session after 5-6 days. There was a spot of blood on the Dexcom bandage.

The second sensor turned out very stubborn to calibrate. It was showing false lows and as much as I tried to educate it with a series of calibrations, it insisted on staying low – until it went high. When I gave up on it after 4 days or so, it came out with an almost 90 degree bend in the sensor wire. Both of these sensors were on the back of my arms, my preferred location these days.

Two days ago I started a new sensor and returned to my abdomen after months of giving it a sensor rest. I have gained about five pounds over the last month or so and my belt was getting tighter. With the change in insulin regimen, I needed to take some action. I’ve kept up my daily walking during this weight gain so I didn’t think increasing exercise was going to help.

I remembered back four years ago when I lost a lot of weight. I was doing a 24-hour intermittent fast once per week. I remember that it not only helped keep my weight in check but also diminished my appetite and tamed my blood glucose traces. I only eat two meals per day, a late breakfast and an early dinner. To do a 24-hour fast, all I need to do is skip my breakfast and fast from after dinner until the following day’s dinner. So that’s what I did today.

I woke up around 2:30 a.m. and my fingerstick was at 110 mg/dl. I wanted to nudge it lower and took 1 unit of Apidra. Did another fingerstick at 5:30 a.m., 127 mg/dl. The earlier 1 unit of Apidra did not have the effect I expected. I decided to inhale 4 units of Afrezza. That did the trick, when I woke up at 7:30 a.m., I was at 87 mg/dl.

I busied myself with some household repairs, nothing overly taxing. My blood sugar locked into a 73-92 mg/dl channel for over 10 hours, like a laser. I’ve seen this before when I’ve fasted but it always seems to surprise me with how tight the BG line can be. I know that my Tresiba basal dose is very close to what I need.

I know I can’t generalize my experience to everyone else but I think a little fasting every now and then would be a good tactic to try when things get crazy BG-wise or you want to put the brakes on a weight gain. Anyone else use intermittent fasting to good effect?


What do you drink while fasting? Only water (and low corrections, if needed)? I think I need to do some fasting for basal testing, although I’m not sure how much it would help since my insulin needs seem all over the place. I’ve read about intermittent fasting once or twice a week and wonder if it would help me lose weight, too. Maybe in addition to lowering carbohydrates and increasing exercise (which I keep talking about but haven’t found the energy to actually implement yet…).

1 Like

Today I was drinking coffee for most of the day. I add full fat cream to my coffee after the first cup of black. I currently use Tic-Tac mints to carb nudge. I should try to drink more water. I’d like to do this fasting every third day for a while.

What I find persuasive about intermittent fasting compared to brute force calorie limitation is that with calorie limitation the body will soon go into starvation mode and outsmart your efforts. Plus I find that intermittent fasting takes almost no willpower for me. Some people intermittent fast by squeezing all their eating into an eight hour window every day. I’ve never tried that but it does seem viable. I think our bodies like to have a break from the constant onslaught of digestion that we ask of it. That’s one of the reasons I don’t like to eat a meal before I go to bed. Now if I can just eliminate the evening snacking, too!

I agree about the calories. It makes much more sense as a way of restricting calories to fast for two days a week than to be on a restricted diet every day. The only long-term fasting I’ve done was in preparation for a colonoscopy, and I found it much easier than I thought I would (except I was allowed calories, which was good because there was one three-hour period where I was low non-stop!).

Is your super-tight control typical of the times you’ve fasted? Or was this time even better than past experiences?

Today was exceptional but I almost always have better lines on days I fast. I’ve noticed this on days I’m forced to fast for medical tests. I’ve also experimented with fasting on days I travel and I end up with better BGs traveling instead of worse, like it is when I don’t fast. Sitting in an airplane seat for hours on end is tough on blood glucose control for me.

Whenever I feel I am out of control or at a loss with my digits, I try to be diligent about some intermittent fasting. It helps me a lot for a couple of reasons. I have pretty severe gastroparesis and it allows my stomach to reset and sort of take a “mini” break from work. Also, it really, really, really resensitizes my body to insulin. I am fairly insulin resistant and IF seems to smooth out some bumpy times!

Thanks so much for sharing. This is making me want to fast tomorrow!

There are a couple of great articles on this…I need to dig them out…:wink:

1 Like

I do daily intermittent fasting… fast from after dinner until lunch the next day… about 18 hours.
Works great for me!


@Ahnalira – So you essentially limit eating to a 6 hour window each day. Do you find it reduces your appetite? If you stray from that routine and eat outside of that timeframe, do you notice a negative effect on your blood sugar?

Makes me wonder where the idea of three meals a day comes from. I eat breakfast at around 6:30 AM, lunch at around 12:30 PM, and dinner at around 6:30 PM. I think I’d be hungry if I missed one of those, but maybe not.

I sort of do this too…never really thought of it as “fasting”, but I have a black coffee and then eat a satisfying lower carb lunch and dinner…

I am a committed intermittent faster. I can get very stable blood sugar (particularly with tresiba, which I am now also on) for up to 18 hours a day, and it’s much simpler to only have to manage the other 6 hours.

I typically eat lunch and dinner only. I don’t snack.

Breakfast time I have a large mug of coffee with cream.

My sisters and their husbands are doing 5-2 plans, which they are all doing brilliantly on and losing some weight. This plan one eats normally (though healthy, lower carb) on 5 days a week, and on 2 days a week (not consecutive) the calories are limited to about 600 for women and about 800 for men.

They say it is the easiest diet plan they have ever used, and seems to be effective.

I am planning to try this next… just have to get my head around it because even with daily IF, HIIT training a few times a week, and total daily calorie intakes of < 2000 calories a day, I am still not losing (even though my blood sugar levels are excellent).

1 Like

I’d call it more of an 8 hour window @Terry4 because I don’t always eat at the same time every day… more like 11:30AM to 7:30PM

Definitely reduces my appetite because stomach is smaller. Also, because I aim toward burning fat rather than carbs, I feel satisfied longer.

Sometimes, I do stray from the routine… when we travel or have friends in town that want to meet for breakfast. When that happens, I stay with protein and vegetables. I find I am less hungry for the rest of the day, for sure. I adjust insulin for more carbs…usually works out ok. But what I do notice is that my digestive tract works much better on two meals per day than three. Everything moves a little slower for me, and I get bogged down by that third meal… if you know what I mean :wink: Two meals works great for me.


I have been doing the 5:2 diet for around 9 months. On two days per week (typically Monday and Thursday) I eat only around 500-600 Calories. I lost about 7 kg in the first 6 months (representing just under 10% of my body weight) so a significant but not dramatic weight loss. Today being a “2” day, I had a medium-sized apple plus a cup of coffee with a spot of milk for breakfast, a coffee mid morning, a cup of “instant” packet tomato soup (16 g carbs) for lunch and will probably have some home made chicken soup with vegetables and noodles plus a salad for dinner (40-50 g carbs).

I am not a low carber (normally average ~200g per day) and on “2” days although my total carbs are probably around 70-80g, this actually represents a higher percentage of my daily Calorie intake than on “5” days.

Along with the modest but encouraging weight loss, I also notice a dramatic effect on my basal insulin requirements. My basal has dropped by 15-20% and this applies to the “5” days as well as the “2” days. I have also had to increase my Carbs:Insulin ration on my pump so my TDD is around 15% lower. I am glad I am using a CGM otherwise I might have had a lot of significant hypos.

The theory behind intermittent starvation diets is that they should switch your metabolism from burning carbohydrates to burning fat. Interestingly as a pump user, I can see this clearly in the effects on my basal requirements. Although I have seen these effects on my insulin requirements and weight, I haven’t noticed a significant change in my BG control, at lease when estimated by my Diasend reports of Average Sensor Glucose, percentage time in range etc.


When I’m being a “good” diabetic and not gorging on fast food, I like to do a high protein breakfast with some carbs, maybe a slice of wheat toast, if my blood sugar is “low”. I like black coffee with half and half. Typically, for lunch, I may have a slice of cheese, deli meat, and turkey. If my sugars get down, I’ll use the temporary suspend feature, which is the best thing about a pump in my opinion. For dinner, I eat whatever my family makes but just leave out the starches. I eat about 900 calories a day when I’m dieting.

@Terry4 This is my first post, I hope I am getting it to appear in the right place. This is a tangent but it caught my attention. You said that the first single unit you injected did not have the expected effect. I am not sure if you were using a pen but I find that single units delivered from a pen hardly ever work for me whereas if I use a syringe they will. Even when priming my pens I dial up to two units because the spring mechanism is difficult to engage for a single unit from a pen from my observation. Sometimes just a couple of droplets of insulin will come out instead of the quick spritz of a whole unit. As far as the intermittent fasting is concerned, I second that it is a useful practice for many situations, I do it to allow me to exercise in the mornings without having to deal with a full stomach. Have found, too, that my BG stays stable unless exercise is intense. Then I just carb nudge with a dextrose tab or two.

I am brand new to insulin pens. They’ve been around for a long time but I’ve been using an insulin pump for a long time. Your comment is interesting. I would like to be able to deliver 1/2 unit doses at times. If a pen can’t do that dependably, that’s a mark against pens in my book. When I was on a pump, I’d do many corrections at less than one unit.

My Apidra Solostar pen ran out and I’ve been using syringes the last several days. It’s less convenient than a pen but I don’t find it too bad. Thanks for your observation. It’s something I’ll be on the lookout for when I resume my rapid acting insulin in a pen.

I’ve heard that the first 1/2 unit in a pen is not reliable. So you can deliver 1 1/2 units reliably, but not 1/2 unit. At least that’s my understanding. When I was using pens I never used just 1/2 unit, so I don’t have any direct experience.

@Terry4 Actually I don’t know what the Apidra pens look like or how they behave. My Humalog pen doesn’t even dial to half units, though. It is my only complaint against the pen and maybe the reason why tight-pivoting is more successful on a pump? If I need one unit correction I will either use a syringe or take two units from my pen and match the extra unit with a time-delayed measured candy. I am not trying to lose weight and don’t consume sugar outside of correction doses so I don’t worry about a little extra carb.

I use Levemir and Apidra pens. I extract insulin from them with BD 1/2 unit syringes. Sounds strange, but it works for me!

i have an apidra reflillable cartridge pen, the junior/pediatric one and it works well for me.