What Is Ketosis Anyway?

The carb craze may be responsible for thrusting the term ketosis into the mainstream vernacular. Before that, it was a word you rarely heard outside of medicine. Before Dr. Atikins and the low carb evangelists came along, you could relegate ketosis to a power point slide in an occasional diabetes lecture and be done with it.

Now it seems like ketosis is the in-word with soccer moms and zone dieters alike. And, while its conceptual popularity has grown, there’s still a lot of misunderstanding floating around about what ketosis is and what it means for your body. Much like belly button lint and the popularity of boy-bands, the ketosis phenomenon is well known yet somewhat mysterious and difficult to explain. So let’s review.

If you don’t have time for the long answer, here’s the short and sweet version:

  • Ketosis is the term for abnormally high levels of ketone bodies in the blood.
  • Ketones are created when the body breaks down fat for energy.

To understand the process of ketosis, and how it progresses to its cousin ketoacidosis, we first need to do a quick review of the functions of the liver and pancreas and the body’s preferred metabolic pathways. Wait … where are you all going? Come back. This won’t be nearly as painful as it sounds, I promise.

You might remember from our review of the abdominal organsthat the liver acts as a kind of metabolic warehouse, storing carbohydrates for later use in the form of gycogen.

When food supplies are abundant and the organs are working correctly, there are many sources of fuel present in the body. There’s the serum glucose, fats and proteins floating around in circulation like a traveling buffet of energy for the cells. We also have our glycogen reserves in the liver and the storehouse of fatty tissues that make your butt look too big in those jeans. Oh, and don’t forget the proteins stashed away in the liver and muscles.

It’s important to keep in mind that the body uses all these fuel sources to varying degrees all the time. The quantities being burned at any given time are entirely dependent on the amounts of fuels present and the body’s metabolic preferences.

When abundant energy sources exist, the pancreas excretes insulin and utilizes glucose (carbohydrates) as its primary energy supply. Glucose in circulation needs to buddy up with insulin to be converted to a fuel source for the cells. That part is important. Regardless of how much serum blood glucose is present, it is worthless to the cells without insulin.

So what happens if the cells can’t find any glucose for energy? This can happen for a few reasons. It might happen in cases of starvation, rigorous exercise or purposeful elimination of carbs from the diet (i.e. Dr. Atkins told me to.) It can also happen if the pancreas stops producing sufficient levels of insulin. (I.e. Diabetes).

Our body’s first alternate fuel source will be those carbohydrate stores in the liver. Remember glycogen? The pancreas excretes the hormone glucagon which stimulates the liver to dump that glycogen into circulation. In normal metabolic conditions, the glycogen stores in the liver might last 48 hours. Then we’re left looking for more energy.

Now the body will turn to its next most abundant supply of fuel, fats. When fats are broken down for energy (ketogenisis) there are several byproducts produced that we collectively refer to as ketones. They are acidic, and if they are produced in sufficient quantities, they will alter the blood Ph and create a metabolic acidosis.

Metabolic acidosis caused by the excessive production of ketones is called ketoacidosis. Ketoacidosis only occurs when ketones are produced in quantities that overwhelm the body’s ability to excrete them. Many of the signs and symptoms we associate with diabetic ketoacidosis are directly related to the bodies attempts to excrete ketones through excessive urination and respiration.

The body’s only two choices for elimination of ketone acids is to pee them off and to breathe them off. Once we understand that process, the hallmark symptoms of diabetic ketoacidosis suddenly make perfect sense.

  • Slow changes in mentation: Body slowly burning through alternate fuel supplies
  • Deep (Kussmaul) breathing: Breathing off ketones
  • Fruity acetone breath: Breathing off ketones
  • High blood sugar: Sugars unable to be metabolized without insulin
  • Increased huger: The body signals the brain it needs more enegry suppies
  • Increased urine output: Peeing off ketones
  • Profound dehydration: Available body fluid used for urine production
  • Increased thirst: The body’s response to dehydration

Instead of attempting to memorize a list like this, I feel it’s far easier to develop an understanding of the physiologic process that drives the symptoms. If you understand what ketosis is, you’ll easily recall the symptoms of diabetic ketoacidosis. Now you know.


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  1. Ketoacidosis is NOT fun. I went through Diabetic Ketoacidosis when I was around 13 or so (type I Diabates), and it was awful. Your symptoms, while totally accurate, do not convey the sheer hell of it all. I looked like a skeleton – lost something like twenty pounds in two weeks (and this was when I was young – I think I weighed 85 pounds or something before I was finally diagnosed).

  2. Steve Whitehead says:

    Glad to hear that you only had to experience it once to get it under control Newt. You highlight the fact that, often, the patient is the best teacher for stuff like this.

    Thanks for your input.

  3. So, do non-diabetic people (aka atkin’s dieters) ever end up with ketoacidosis? What is the effect on healthy folks of these ketone bodies?

  4. Steve Whitehead says:

    Great question AJ. And one ripe for debate. Depending on who you ask yes … or … no. Confused? Me too.

    The media (including JEMS Magazine have discussed case reports of Ketoacidosis in non-diabetics using low carb diets.

    The low-carb culture blows off those few cases as misunderstood and unrelated to the low-carb diet. They claim that high blood glucose needs to be present before ketosis can convert in to ketoacidosis.

    That sound s a bit sketchy to me. But we can say that, while it may be possible to induce ketoacidosis through carb restriction alone, it certainly isn’t common.


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