Hi Jim,
Thanks for the most interesting question.  As Alec said, ketosis can 
vary according to  activity level as well as amount of fat, protein, and 
total calories  consumed. It can also vary according to variations in 
base metabolic rates, intestinal absorptive capacities, gall bladder 
health and output, and various hormonal factors including ghrelin and 
leptin production. There is some evidence to suggest that sex hormones 
also play a significant role in the variations of ketosis from one 
person to the next.

The usual way to measure level of ketosis at home is to use ketostix. 
(Their presence can also be measured in the breath and the blood, but 
not with Ketostix... I tried it just to see if they would detect them in 
either blood or saliva and was unsuccessful.) Urinate on the reagent 
area of one stick ( a strip of paper with a blob of reagent on one side 
of one end). The reagent will change color indicating the relative 
quantity of ketones in the urine. A color scale appears on the side of 
the container which allows you to hold the wet end of the stick near the 
color chart and identify the closest match. The scale goes from: 
negative/0/0; to Trace/5/0.5;  small/15/1.5; moderate/40/4.0; and the 
last two color patches fall under the same "large" category - large/80/8 
and large/160/16
The first measurement is milligrams per deciliter and the second one is 
milimoles per liter. I prefer to use the mg/dL scale because it uses 
whole numbers.

One of the reasons that counting calories in ketosis is meaningless is 
because we are excreting many calories in our breath and urine while in 
ketosis. Our livers make some ketone bodies under most circumstances but 
I have read that ketone production diminishes with increases of 
insulin.  Some cells, particularly the heart,  preferentially use ketone 
bodies for energy so, under normal circumstances, these cells use up all 
the ketone bodies produced.  It is only when our reliance on fat for 
energy increases that we produce excess ketones which are excreted in 
urine and in our breath.

About 80% of deaths among those with type 2 diabetes are due to heart 
attack or stroke. I have often wondered just how much of that is caused 
by the diminished availability of ketone bodies to fuel the heart. If 
that is a factor in diabetes-related heart and vascular disease, then 
the use of exogenous insulin and the various drugs that enhance cellular 
uptake of glucose despite insulin resistance are actually moving in the 
wrong direction.

I'm sorry to go on and on, but I am wrestling with some of these complex 
interactions myself, especially as they relate to seasonal variations in 
fat accumulation and loss.

Best Wishes,
Ron


On 05/01/2011 11:32 AM, [log in to unmask] wrote:
> I am now very confused about ketosis.  Like pregnancy, I thought you 
> either were or weren't in ketosis.  That as long as you kept your 
> daily carbohydrate intake below a certain amount (a "window" that of 
> course varies by person), your body would remain in fat burning mode.
>
> So if there are degrees of ketosis, are those degrees dependent upon 
> how much carbohydrate you consume within the window?
>