Ketoacidosis versus Ketosis
Some doctors and other medical professionals confuse ketoacidosis, an extremely abnormal form of ketosis, with the normal benign dietary ketosis associated with ketogenic diets and fasting states in the body. They will then tell you that ketosis is dangerous.
The difference between the two conditions is a matter of volume and flow rate*:
*See this reference paper.
Here's a table with actual numbers to help show the differences in magnitude:
Here's a more detailed explanation:
Fact 1: Every human body maintains the blood and cellular fluids within a very narrow range between being too acidic (low pH) and too basic (high pH). If the blood pH gets out of the normal range, either too low or too high, big problems happen.
Fact 2: The human pancreas is an organ which secretes insulin, a hormone that helps the body manage blood sugar and fat storage. Without insulin, the body cannot utilize glucose for fuel in the cells, AND cannot store fat in the fat cells.
Without that message from insulin, large quantities of fatty acids flow out of the fat cells and are broken down in the liver into a ketone body called acetoacetic acid which is then converted to two other circulation ketone bodies, Beta-hydroxybutyrate and acetone.
This is ketosis, but an unrestrained, abnormally excessive ketosis.
The danger of keto-acidosis is in the amounts of the ketone bodies being released. Because ketone bodies are slightly acidic in nature, and so many are released at once in a ketoacidosis situation, they build up in the bloodstream.
The sheer volume quickly overwhelms the delicate acid-base buffering system of the blood, and the blood pH drops to become more acidic than normal.
It is this low pH, acidic condition known as acidosis which is dangerous, not the ketones themselves.
Acidosis symptoms include fruity breath (from the acetone), nausea, hyperventilation, (deep, rapid breathing) dehydration and low blood pressure, as the body tries to rid itself of the abnormal amounts of ketones through the lungs and urine.
If left untreated, ketogenic acidosis can result in a coma and death. Treatment includes the administration of insulin to slow the ketosis and fluid replacement.
Diabetics can develop diabetic ketoacidosis if they don't inject enough insulin to compensate for activity and food intake.
Ketogenic acidosis can also happen during:
Benign Dietary Ketosis is Controlled
The ketosis that happens on a ketogenic diet is not dangerous because it is regulated by insulin levels within the body.
It's simply the metabolic process of burning your own body fat for fuel, and unless you are diabetic and lacking insulin, or you are a raging alcoholic, it is perfectly safe. Levels for people with a working pancrease and insulin production rarely get above 8mM.
Here's another explanation from Dr. Peter Attia, a physician with extensive knowledge about ketosis.
How Do I Check for Ketosis?
If you have started a ketogenic diet and want to be able to check your ketone levels, there are several ways to do this.
You can buy ketone stix, and check the levels of ketones in your urine. This method has been the most common method for years, but recently, several companies have developed a blood ketone meter for home use.
This method of checking ketones in the blood is much more accurate, but is also much more expensive. Jimmy Moore has a nice post on using the blood meters here.
Below are links to the Keto-Stix for urine checks, and the various brands of ketone meters for blood checks.
If you would like to read more, Jeff Volek and Steve Phinney discuss the new method of checking blood ketones in their book "The Art and Science of Low Carbohydrate Performance".
and this Volek and Phinney book is a good introduction the science of ketogenic diets.