High Ketones and Low Glucose, Cause for concern?


(Jonathan) #1

Background: Intermittent fast, window is from 6:00 AM to 1:00 PM

Ketones typically between 2.5 and 4.5 mmol/L

Glucose typically between 72 and 90 mg/dl

Tonight I had a fairly intense workout (an hour of mtn biking on some aggressive trails)

got home and tested (about an hour after the workout) and my ketones were at 6.9 and glucose was at 72. Thought the high ketones were interesting but not concerned.

Tested again about 2 1/2 hours later (right before bed) and now my ketones are >8 (meter just shows “high”) and glucose has dropped to 57.

Should I be concerned?


(Vic) #2

Welcome Jonathan,

Looks normal and good.

Cool nickname :sunglasses:


(Michael - When reality fails to meet expectations, the problem is not reality.) #3

Short answer: no.

Longer answer: no…


(Karim Wassef) #4

My highest was 9.3 and paired with a glucose of 47. No issue. My only concern is if both are low.

Here’s my first extended fasting experiment data from 2019… extended then cyclical


(Karim Wassef) #5

Also - since this might happen at some point too - my lowest glucose was 33 paired with a ketone reading of 6.4 … also fine. Just keep up with your salts.


(Bacon by any other name would taste just as great.) #6

You don’t state why you are concerned, but I assume it has something to do with diabetic ketoacidosis. A diagnosis of that condition relies on both a high ketone level (over 10.0) and a high glucose level (well over 100). If your pancreas is secreting insulin at all, you are safe from diabetic ketoacidosis. There is a condition called euglycaemic ketoacidosis, in which glucose does not rise, but it is the result of taking certain specific medications (in particular SGLT-2 inhibitors), and your doctor would have warned you about that risk.

Ketone and glucose levels are highly variable throughout the day. Ketones tend to rise during fasting, and glucose tends to fall. This is the body working as designed. After you’ve been eating a ketogenic diet for a few months, you will probably notice that your ketone readings will tend to be lower and not rise so high. This is also normal, because as the muscles fully switch back to metabolising fatty acids (fat-adaptation), the liver drops ketone production to better match demand.