“There are several ways you can determine whether you’re in ketosis.
One: you can use the classic teaching, which is you can go and get what are called “keto sticks”. These are urine-dip sticks that will assess, sort of grossly, your levels of urinary ketones. That’s number one.
Number two, and the more accurate way of doing it, is to actually check with a blood ketone meter. That’s going to give you a very, very accurate assessment of your blood levels of ketones. Ketosis is defined as a level of blood ketones .5 millimolars or greater.
Another very, very rough way of checking is to actually have someone smell your breath. Acetone, which is one of the three ketones that the body produces, has a sort of a sweet smell. If your breath smells sweet, in all likelihood, you are in ketosis. Interestingly, there’s a technology that has been developed that will assay the amount of acetone in your breath, sort of like a breathalyzer, except for ketones and not for alcohol. That will give you a rough indication as to whether or not you are producing ketones.”
Dr. O is a Team BPI Sports’ fitness and nutrition expert.