The FastDay Forum

My husband is type 1 diabetic so I stole some of his ketone sticks (he doesn't use them, so stop giving me evils) and I thought I'd test my urine during a fast day.

The result?

No ketones - what. so. ever.

Epic fail I thought fasting produces ketones? (as a consequence of burning fat) Or have I completely lost the plot here?

Pip, from what I've learned here, the ketostix are not reliable. (I have them and just tried the same thing with the same negative result.) The reason is not that they don't work but that they measure ketones being excreted, but long before your body gets to that stage it may well be burning ketones internally. I think. Someone more expert might be able to put it better.

Pip, from what I've learned here, the ketostix are not reliable. (I have them and just tried the same thing with the same negative result.) The reason is not that they don't work but that they measure ketones being excreted, but long before your body gets to that stage it may well be burning ketones internally. I think. Someone more expert might be able to put it better.

Hmmm but I thought the sticks were uber sensitive? Surely they have to be, to help diabetics?

from an old topic (search for 'ketostix'):

I wouldn't read too much into the ketostix not being positive. If you are using the ketones produced for energy then they will not be getting into the urine. They probably wouldn't show positive until you use up all your glycogen stores and as you may have up to 2000 or so calories stored as glycogen and you do produce some ketones before you run out of glycogen, it could take a while. Some say as much as 4 days!

That's as much as I know! And it seems I misremembered about having used up all the glycogen stores...

Oh dear. We need more nerds. WE NEED MORE NERDS IN HERE!!

Peeing ketones is not a good thing!!! The fat should be metabolised in your body. If your body pees ketones then there is something wrong with you!!!!!!!

I think it takes longer fasting than 24 hours before you're peeing ketones. I know that ketones are a big thing with the Keto diet though, from what little research I did into it before I heard of 5:2.

Diabetics have ketone sticks to warn of very high levels which are dangerous when combined with high levels of blood sugar, they aren't looking for low levels.

Low carb eaters / dieters and fasters will often show ketones in urine if the blood ketone levels are sufficiently elevated. If ketones are being made and used the levels in a well adapted person don't rise very high so a negative test is quiet common even in Atkins induction.

It takes concentration to sustain ketosis - low carb and moderate protein. Someone eating more than 50g a day of carbs (200 cals) is unlikely to be in nutritional ketosis.

[carorees]

Your body can burn fat without producing ketones, as many organs (e.g. muscle, heart) can use fats directly for energy. When glycogen stores get low and so the supply of glucose is limited, the body starts to produce ketones, because not all tissues can use fats directly. In the production of ketones there is one ketone that cannot be used by the body (acetone) but is created as part of the conversion process. This and any other unused ketones are excreted in urine and in the breath giving people the unpleasant breath. The ketostix being negative does not mean that you are not burning fat or even that you are not producing ketones just not enough to be in high enough concentrations in your urine to be detected. If you drink a lot on fast days the increased urine production can dilute the ketones below the level of detection anyway. The best time to check is probably in the morning after the fast just before you eat breakfast.

Your body can burn fat without producing ketones, as many organs (e.g. muscle, heart) can use fats directly for energy. When glycogen stores get low and so the supply of glucose is limited, the body starts to produce ketones, because not all tissues can use fats directly. In the production of ketones there is one ketone that cannot be used by the body (acetone) but is created as part of the conversion process. This and any other unused ketones are excreted in urine and in the breath giving people the unpleasant breath. The ketostix being negative does not mean that you are not burning fat or even that you are not producing ketones just not enough to be in high enough concentrations in your urine to be detected. If you drink a lot on fast days the increased urine production can dilute the ketones below the level of detection anyway. The best time to check is probably in the morning after the fast just before you eat breakfast.

Bingo! Thank you carorees. I think you've cracked it! I will test in the morning.

The urine sticks apparently react only to acetoacetic acid, not to acetone or beta-hydroxybutyric acid. My glucose/ketone blood meter reacts to the latter (B-OHB). Why is nothing simple !

[carorees]

I would have thought acetone would be the most useful to measure as it is not used by the body so more likely to be found?

I would have thought acetone would be the most useful to measure as it is not used by the body so more likely to be found?

Ain't that what we use to remove nail polish???

[carorees]

Yep!

And it can be found in our pee???