The FastDay Forum

[carorees]

I don't think there's enough to save you money on buying nain polish remover!!

Trust you Caroline! Your one-liners always crack me up!

I don't think there's enough to save you money on buying nain polish remover!!

Pfffffffffffft...

Perhaps acetone is harder to determine with a colourimetric or enzyme based test ? B-OHB tends to be the one measured in blood in clinical trials.

"Assays that measure acetoacetate through urine testing may not identify the onset and resolution of ketosis as quickly as those that quantify beta-OHB levels in blood, since acetoacetate or acetone can increase as beta-OHB decreases with effective treatment."

http://www.ketogenic-diet-resource.com/ketones.html

So I tested this morning (fast was yesterday) and there was just trace ketones (if that!)

Bummer.

"normal" is no ketones, so a trace is good.

[carorees]

As I said it doesn't mean you are not making ketones, particularly as we know from PhilT's post that the sticks test for a ketone that is used by the body for energy...if you use the ketones for energy they can't appear in the urine. The bad breath plus this trace suggests you are making ketones. I wouldn't worry about it myself.

Volek & Phinney reference a study showing urine ketos are an unreliable measure of the (relevant) blood level. The Paleo community's experience endorses this too. Apparently in the US there are 'finger prick' test blood, but I've not seen any UK sites selling these. They are used by Diabetics I believe.

http://www.simplicityhealth.co.uk/blood ... optium.asp UK blood ketone meter, strips expensive usually available on Ebay or imported cheaper.

I found a useful study http://ajcn.nutrition.org/content/28/5/507.full.pdf that looked at the impact of modest glucose intake on otherwise fasting subjects. The graph below shows how urinary ketones fell when glucose was introduced mid-fast for 7 days :



The one below shows how blood ketones rose at the start of the fast when the 150g / 600 kcal glucose was withdrawn :-



The levels of B-OHB are measured in blood meters, ketostix measure the acetoacetate which is less dramatic in its response to glucose withdrawal.