Intermittent Fasting with Type 1 Diabetes

Intermittent Fasting. What is it and is it safe to do with type 1 diabetes? I was recently asked to post about intermittent fasting, so here goes nothing. **Please see excerpt at the bottom of this post if you have any doubts! One thing I want to clarify right off the bat, I’ve never been a big breakfast eater, so I’ve theoretically been intermittently fasting for quite a few years!

What is intermittent fasting?

Intermittent fasting is simply taking an extended period of time off from eating. Most of us do this each night for at least 8-12 hours. Important note: it’s still important to drink liquids like water, black coffee, or tea.

The easiest way that I’ve incorporated intermittent fasting into my lifestyle is by following the 16/8 rule. Basically, that boils down to 16 hours of fasting, and an 8 hour time frame to eat. For me, this is simple as I don’t eat breakfast, I never really have. So I generally eat my first meal of the day at 12:30 (noon), my last meal at 18:00 (6pm), followed by fasting until lunchtime the next day. Although Dr. Bernstein does not support intermittent fasting, I still do it. It is not an extra choice that I make, I simply just do not eat breakfast (although I do on the weekends).

What are the benefits of intermittent fasting?

Stable blood sugar. For me, the benefits of fasting from my supper time meal until noon the next day are clear. My blood sugar is stable from 18:00 on day 1 until 12:30 on day 2, all without much effort. That mean’s I eat between 12:30 and 18:00. That ranges from 16-18 hours of stable blood sugars. However, basal rates need to be checked to make sure that intermittent fasting is a safe option. Actually, running a basal test is also, in effect, fasting!

Some other benefits that intermittent fasting is thought to provide are: weight loss, better fat burning, lower blood sugar levels.

When can intermittent fasting be dangerous?

Blood sugar issues. In order to be successful with intermittent fasting, it’s important to have basal rates on target so that blood sugars do not fluctuate in either direction, low or high. Once blood sugar is out of range, it should be corrected. Example: I’ve had times where I drop low in the morning without eating, lower than 65 mg/dl. At this point, I needed to eat a glucose tab in order to bring my blood sugar to normal range (70-100 is my target). The same goes for too high of a blood sugar.

Overeating. If overeating becomes an issue, perhaps it’s better to eat three meals a day instead of overeating as a result of hunger.

Elevated cortisol levels. This is a big one! If insulin resistance seems to become an issue, maybe intermittent fasting isn’t the best approach. It is thought that cortisol may be released when skipping meals for an extended period of time, leading to insulin resistance. I personally do not experience this, but be mindful.


In the end, it’s important to do what’s best for you. If intermittent fasting seems to deliver the opposite results of what you’re striving for, then perhaps it’s time to reconsider doing it in the first place.

Does anyone else fast with type 1 diabetes? What have been your experiences?


**I am not a doctor and I am NOT qualified to give medical advice. The above is my opinion and a bit of research which is not meant to substitute medical advice.



  1. Hello I am type 1 diabetic and I have been doing the 16:8 fasting for about a week now….I find that my glucose levels rise so much throughout the day around 300!!…is this my body getting rid of excess glucose by using the stored glucose? or maybe cortisol being released because my body goes into emergency starvation mode? Halp.


    1. Hi there, if your glucose is rising by over 300 mg/dL, I would think it could be your basal insulin (long acting) that is causing the biggest issue. Have you done basal testing? I have a blog post on how to do it. Let me know if yes or no! I have a hard time thinking it is cortisol that’s to blame, but maybe!


  2. So glad that I found this post, absolutely mind-opening. I just begin to study the science of IM and had watched a BBC research study on that, wonderful research result. I’m also a follower of Dr. Bernstein YouTube channel but couldn’t find his comments on fasting. Would you mind tell me which seminar he mentioned this topic? Just want to have a reference and hear different opinions. Your story gives me hope in seeing good effect of IM on T1 diabetics! Big big thannnnk you!:)


  3. I also have been intermittent fasting with extended fasts as well (2-5 days) … once or twice a month … I do one meal a day (OMAD) … my sugars are better then ever … my graph is flat lined (cgm). I feel great, clarity, lifted brain fog, and energy levels I didn’t know existed without the help of stimulants (which I am now completely off of). I’m losing weight like crazy … I was never super fat but over the last few years I gained about 50 lbs :(, but it’s coming right off and I can’t complain about that. I’ve been looking for another t1d to do this with, but it seems like it’s a big no no in the community.

    I was a carb hungry binge eater and now the hunger and cravings have passed. I’m so happy with my decision to try this and stick with it!!

    Would love to talk more about this topic !

    Liked by 1 person

    1. Hi Kat, that’s fantastic news. Your story is incredible. Thank you so much for sharing! I think others will benefit from your comment.
      Feel free to email me or message me on Instagram or Facebook! Hit the contact button on my blog. Looking forward to hearing from you.


    2. Hi I just came across this article in my search for information about type 1 and intermittent fasting. Are you still doing this? How has your blood sugars been while following ? I would love to hear more about this. Thank you Amy


      1. Hi Amy, I still do IM. Typically, I eat dinner at 7pm or earlier, then I am fasting until 12pm for lunch the next day. It works very well for me. What questions do you have?


    3. Hey Kat

      I know it is waaaaaaay later but if you are still looking for someone to do this with please let me know. I seriously need a support group and cannot find another T1 to do this with as everyone seems to think it is not suitable for us


  4. I just found your blog and I am stunned, it’s like I found a diabetes twin… I have so many comments about everything and I hate typing and don’t know where to start but YES YES YES!!!! The feet to floor, intermittent fasting, focus on SD, high-low range, cost of proving a point, low-carb choices and I’m guessing so much more!!! Can’t wait to keep reading, thank you!!! I’m in my first year with t1d and have yet to meet another t1 in person. I love the online community but have felt like a lot of my choices seem “controversial” despite how well I feel I’m doing and have honestly felt scared to talk about any of it. Your blog and Instagram account are SO inspiring and motivating. Thank you!!


    1. Best comment ever 😍😍 don’t ever be afraid of speaking out and continuing your journey – esp because it sounds like you’re on the right path! And thank you for reading!!


  5. I have been trying intermittent fasting for a couple of weeks. I’m still working through my basal rates for occasional highs. Here’s an example: When I got up this morning my BG was 160. I did not want to stay that high so I “bolused”. Am I completely defeating the purpose and for that day eat anytime until my normal feeding window would close? If I have to bolus like this a couple of days a week, is there any potential benefit?


    1. I don’t think you’re defeating the purpose. It’s important to correct high blood sugars, so your strategy is the same that I would follow. By IF, you’re taking the carb guessing game out of one more meal, so allowing normal blood sugars to last much longer without influence. I aim for that before any other health benefits.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s