"Ketosis" isn't a place, although some might say it's almost a state of mind. In very simple terms, ketosis is when the body utilizes ketone bodies (fat) for fuel rather than glucose (sugar). Our bodies can use either fuel for energy and keeping the lights on but in general can use one or the other. (It's not 100% for either but rather the body will burn either glucose or fat for the vast majority of its needs at any given time)
In a previous post I wrote a bit of a general overview of this in defining the ketogenic (or LCHF diet). In this post let's dig a bit deeper into what it means to be in ketosis and how to tell if you are. Keep in mind that being in ketosis is NOT the same as a dangerous condition called ketoacidosis which can occur in Type I diabetics. Measurements for ketoacidosis will be several magnitude higher than good old, run of the mill ketosis. See the disclaimer below about me not being a medical professional and all that.
If you are already on a low carb diet, you may be in ketosis and not know it. Or you may assume you are in ketosis - burning fat for fuel rather than glucose - but you're not quite there yet. Measuring ketones is a great way to monitor your system. It can also be a great tool to figure out which foods aren't cool for you. Some folks can eat more carbs than others and remain in ketosis, burning body fat at a nice pace. Lucky people.
I have to be quite strict. 20 grams of carbohydrate a day. Usually less than 15. It's not hard or depriving, as you can see what I might eat on any given day.
The point is, if you want to lose body fat - and get the many other health benefits of being in ketosis (more to come on that topic) - measuring for ketone bodies can really help you get there.
So, how does one measure?
There are three generally accepted methods to measure ketone bodies: breath, urine and blood. Yikes. Sounds rather gruesome when you write it out like that...
Fear not. Any of the methods is pretty easy. But each requires different 'equipment', of course. (Let's not think about the consequences of confusing the blood test for the urine test, or worse, the urine test for the breath test! Ick!
When first starting, the most economical route is to test with urine strips. They're available widely, are affordable and super easy to use. As the name implies, you get a little strip and, well, do your thing. The strips are reactive immediately and will present with a color on the tip that can be compared to a chart on the side of the bottle. The color will range from light taupe (not in ketosis) to deep purple (ketone city).
Easy and reliable. And very compelling when first starting. These strips were what I used when I commenced on following the low carb/high fat plan. It took just a few days for the little strips to show I was 'spilling over' ketone bodies in my *ahem* water. And that's how the strips measure. Excess ketones are washed away. (Specifically, they measure acetoacetate in the urine). After some time on the diet, as you are fully 'keto-adapted' and running full time on ketone bodies rather than glucose, the spill over can diminish. That's why these are good to get started and to monitor as you learn what foods are really working for you and which aren't. (I'm looking at you, fruit!) I didn't make it through the first whole bottle when I got going before it was time for me to move on the to next - and, for now, probably the gold standard - of testing: blood.
Testing blood ketones is simple, but does involve the tiniest little pin prick. So may not be a good choice some. I use a Precision Xtra device. It measures both glucose and ketones, depending on which test strips you use. It is widely accepted that a reading of 1.5 - 3.0 is the sweet spot for nutritional ketosis. Keep in mind that, as with all things in life, there can be variation to this. I seem to run high much of the time. I keep a lot of data on a massive spreadsheet going back 15 years (yes, 15. Thank goodness excel has unlimited cells) and my average blood ketone reading is 2.7.
I also measure my blood glucose with this device. It was my direct path to Type II diabetes that set me on this eating protocol. I'm thrilled to say my average readings over the past year or so is 80.4.
The testing is easy enough - prick your finger with the included lancing device (sounds medieval but it's no biggie), get a drop of blood on the tip of the strip which is inserted in the meter and wait about 10 seconds for the results.
Downside is that the blood ketone test strips are pricey and need to be purchased separately. I have yet to find a bricks and mortar store that has them. If you know of one, let me know!
I have purchased them at Universal Drugstore out of Canada. You have to jump through a couple of hoops to purchase with a credit card and delivery can take a bit longer, but they're less expensive, particularly when buying a few boxes. [BTW, the expense of the food and devices I incur for being on the ketogenic diet are so offset by the improvement in my health, happiness and frame of mind there's not even a contest. I'll write more about the costs overall of eating this way in another post. It's a topic that comes up a lot when folks first hear about it..]
For those keeping track, whereas the urine strips measure acetoacetate, blood test trips measure beta-Hydroxybutyrate.
A third way to measure ketones is via a Ketonix breath analyzer, which measure acetone. You purchase it once and there's no finger pricking involved. I have no experience with a breath analyzer other than when I was part of a trial to see if alcohol consumption impacts ketosis. (For real! It was cool to be included. I'm hoping they'll run a trial to find if spa massages impact ketosis. So far, no one has taken my suggestion.) My understanding is that the device can be a bit persnickety and the readings less precise than blood testing. But that's just what I've heard and I have no direct experience one way or the other.
So, if you want to get in to a fat burning state and don't know if you're there yet - and enjoy self-experimentation and data - give measuring your ketones a try. Let me know any questions or comments. Share your experiences. Have you used the Ketonix breath analyzer? I'm curious about that.
The information I present here is based on my own experiences and personal research. While I’ve been fortunate to have much person-to-person exposure to leading researchers, physicians and journalists regarding the ketogenic specifically and LCHF (low carb/high fat) more generally, we are all responsible for our own choices, including what we put in our mouths. I welcome questions, comments and even civil criticism. I’m still learning. So, i you have something to add, go for it. Thanks! - Casey