Low blood sugar reading but feel fine

(ks) #1

I’ve been doing IF for about 3 weeks. I typically will do anywhere between 16/8 to 20/4 with the occasional longer fast thrown in. I’ve done a 24, 36 and 48 hour fast before. I decided I wanted to try a 5 day water and coffee only fast. I’m not diabetic.

I’m currently about 48 hours through my intended 120 hour fast. Yesterday I got a glucose and ketone monitor. I took my first reading yesterday evening (about 24 hours into the fast) and it was 81. This morning it was 98 (all good). About 30 minutes ago I took a reading and it was 46 or 48. I knew that sounded low so I’ve been doing some reading online and it sounds like that is very low and possibly concerning. My ketone level this morning was .3 and recently was .6.

The thing is, I feel fine. I wouldn’t have thought anything of it if I hadn’t gotten the meter and seen the low reading. I don’t want to be stupid and risk having a major issue, however I also don’t want to break my fast if this is just the process of my body switching to ketosis and having low blood sugar since I’ve never been in ketosis before. I have about 50 pounds to lose so no worries of not having adequate fat for my body to use…

I’d appreciate any thoughts. I will definitely eat something if I start having significant symptoms but I am a couple of hours from going to sleep. Do I need to be concerned? As long as I feel fine should I continue with my fast? Is there any glucose level that I need to be really concerned with?

Thanks for any help.

(Susan) #2

Personally I would say yes – as long as you feel fine, you are doing fine =). I started Keto almost a year ago, and I have never used any of the Sticks or Meters --I know a lot of people love them, but they are not a must to have for Keto. I have done lots of fasting and have never worried about that.

If you don’t feel well, then by all means, eat something. Fasting is awesome, but remember that it is a voluntary thing, and should only be done when you are comfortable doing it =).

(Cancer Fighting Ketovore :)) #3

I wouldn’t worry to much. I’ve had low glucose like that, but my ketones were also much higher. Just keep an eye on things, and if you feel bad, stop and eat.

(ks) #4

Thanks. So I just took the reading again (about an hour after last test). I had a cup of coffee with a teaspoon of coffee mate powder (I typically allow myself that while fasting a couple times a day). My bg went up to 76 and my bk was 1.0 this time. I immediately did a second bg reading just to confirm and that time it was 82. Could the coffee and powder have raised it that much or is it more likely that the first low reading was an error? Thanks again for all of the help.

(Susan) #5

The coffee mate powder isn’t Keto --so that might be what is messing you up. The coffee is fine --but if you cannot have it black --then you would be better off using Heavy Whipping Cream then the coffee mate =).

(ks) #6

Figures, I had bought a huge tub of it from Costco so I figured I would use that instead. Oh well, guess it is time to get some heavy whipping cream.

(Justin Jordan) #7

But yeah, if I get a weird reading, I always retest.

(Cancer Fighting Ketovore :)) #8

76 and 82 are within the available error range, which is to say they are both valid. You could average it to 79 :slightly_smiling_face:

#9

Anecdotally (take a look at the comments):

I’ve seen similar discussions where those on a keto diet say they sometimes have blood sugars in the 30’s and 40’s and feel fine.

What should a “low blood sugar” be for someone on keto? Someone who is no longer using glucose as the primary fuel for the body?

(Cancer Fighting Ketovore :)) #10

FWIW…

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Courtesy of my CGM. FS = fingerstick, BK = blood ketones

#11

I was watching this video:

…and they mentioned a study done on obese patients that had been fasting for several months. So, high ketones, low glucose. They administered insulin to lower the blood glucose even more. The patients were operating fine with glucose levels in the single digits, which should have meant a diabetic coma…

(ks) #12

Thanks for the comments. This morning (60 hours) my bg was 82 and my bk was 1.3. Wishing the ketones were higher but I haven’t been in ketosis before so I’m guessing my body is taking longer to adjust. I also use the Precision Xtra which I’ve read is usually a lower reading that the KetoMojo so maybe that is a part of it also. The low bg readings in the 40s seem alarming but I guess the main indicator is how I feel and I’m glad I didn’t break the fast. Thanks again!

(Jack Bennett) #13

Exactly. I recall Phinney speaking of some interesting experiments from the 1960s - possibly by Cahill - where they took fasted subjects in ketosis and gave them insulin bolus to essentially wipe out their blood glucose.

In a non-ketosis state this would be extremely dangerous and possibly life-threatening, because the subject would immediately enter a hypoglycemic coma due to loss of fuel for the brain. (This is a risk for T1 diabetics if they overdose on injected insulin.) But these subjects were fine, with their brains operating on ketones.

Maybe someone else also recalls this, or has a link to the actual paper?

#14

Sounds like the study referred to in that last video I posted. I had hoped the YouTube page would have a link to it, but no.

(Jack Bennett) #15

Oops, yeah - sorry, missed your video that you posted before me. It’s probably the same study, or a very similar one.