Is your body in a state of Ketosis? If you eat some form of low-carbohydrate plan, this is a question that commonly comes up, especially early on in the process. The amount of carbohydrate restriction required to enter a state of Ketosis varies from person-to-person. A general rule of thumb is below 50 grams/day, though some individuals propose as long as you keep your hourly carbohydrates as much under 9 grams, it is sufficient.
For most people, after a week or so of eating low-carbohydrate their bodies will be keto-adapt - their bodies will begin to shift from using glucose as a primary fuel source - and start using fat as the main fuel. One product of this process of fat breakdown in the body via ketogenesis is the production of ketones. These compounds fuel the brain, and have been shown to be the preferred brain fuel - giving many on low-carbohydrate eating lifestyles "clearer thinking". I personally have experienced this and it has made my graduate career much easier. I'm maintaining my 4.0!
The older way of testing whether or not you are in ketosis is by purchasing urine test strips. Generally, it tells you whether or not you are passing ketones. This is unreliable as the information you are receiving is hours old. The newer method, as mentioned in the Fat Head Blog is to test your ketone levels by electronic meter. The advantages of testing by meter is that you can accurately obtain your blood ketone level, it takes a matter of seconds and you can do it anywhere - no trip to the bathroom necessary.
Let's say you obtain a meter - how do you even read the results? Most meters will not check ketone levels, they are made for individuals concerned about blood-glucose concentrations (i.e. diabetics). If you are interested in obtaining a meter which checks ketone levels (free of charge), let me know in the comments.
As Tom Naughton on the aforementioned blog explains, "Drs. Jeff Volek and Stephen Phinney call nutritional ketosis: a blood ketone level of between 0.5 and 3.0 mM.". So anywhere in between means you are in a good place. Jacqueline A. Eberstein, R.N., who began working with Dr. Robert Atkins in 1974, gives some great information on ketone levels:
Blood levels of ketones:
On low carb---1 to 2 mmol/L
More than 20 days fasting---10mmol/L
Diabetic ketoacidosis---more than 25mmol/L
Having a meter with a glucose blood test is also nice as it gives confirmation that you are on the right path. A quick glucose blood test calculator/analyzer is here: http://www.medindia.net/patients/calculators/bloodsugar_chart.asp
Keep in mind, I have never been pre-diabetic, diabetic or otherwise. I obtained a meter recently out of curiosity and for n=1 purposes. I took my first ever self-administered separate ketone and glucose tests:
Ketones = 1.5 mmol/L
Glucose = 85 mg/dl
This was after 2 large cups of coffee, which included about 6 tablespoons heavy whipping cream and around 1 tablespoon of coconut oil.