Ive just been reading up about this myself as have just got some ketostiks for the first time.
I had been going by the 'funky skunky' breath method too
Hope this helps you out
In The X Factor page 136-137 it is written:

KETOGENIC KICKOFF

Within the first 48 hours on Ketogenics, your body should switch its metabolic functioning and begin using fat as fuel instead of sugar. As this happens, ketone bodies - the by products of fat breakdown from your cells - will be released into your bloodstream. They will then be eliminated from your body through your breath and your urine. Ketones are biochemical proof that you are consumimg your own stored fat. Ketosis suppresses your appetite - so much so that after the first 48 hours you will probably no longer think about food obsessively.

Measure It

Ketosis can be monitored by measuring the levels of ketones in your urine. This is a good indicator of the balance of carbohydrate and insulin in your body. To make sure that you are not eating too many carbohydrate-rich foods, it is important that you test your urine for ketones twice a day - before breakfast and agian before your evening meal.


'For successful ketogenic fat loss, your ketone levels must be maintained between trace and small (0.5-1.5mmol-l) You will be able to test these levels using urinary test strips which you can buy at any pharmacy. They are called ketosticks~.

Because the presence of ketones in the urine indicates that fat burning is taking place, you might be tempted to believe that the higher the level of ketones the more quickly your body is burning fat. This is not the case. Ketone levels above 'trace' and 'small' - in excess of 'moderate' (4-6mmol) - can stimulate insulin secretion. This in turn would lead to a reduction in fatty acid release from fat tissues and a consequent slowing of fat loss.
So it is essential that you maintain ketone levels at 'trace' or 'small'. If your ketone levels are greater than 4mmol, you may need to increase the number of low glycemic index carbohydrates you are eating slightly or reduce the amount of excersise you are doing. If you are not producing ketones, chances are that you eating too many carbohydrate foods or you may need to do more exercise.

If you do not appear to be in ketosis within the first three or four days, or if later on in your Ketogenics programme you go out of ketosis for 24 hours or more, check back to your diary and find out if there are any of the Ketogenics rules hat you may not be following. For instance, are you still drinking coffee? Caffine inhibits Ketogenics by causing the liver to release extra glucose into the bloodstream. Don't drink it.
If you continue not to show ketones in your urine you may need to add some insulin-sensitising nutrients which may be added as supplements to encourage fat burning: chromium, magnesium omega-3 fatty acids, lipoic acid and n-acetyl carnitine, for instance (see page 154-7).

In most people, the metabolic changeover from burning glucose to burning out two days, during which you may feel hungry. If you break your and have a starchy meal, it will take you another two to three days into ketosis. This is the only time when you are likely to be hungry on ketogenics.