A common misunderstanding regarding the metabolic effects of low-carbohydrate diets concerns the formation of ketone bodies. The presence of ketones caused by fat burning is often confused with ketoacidosis resulting from uncontrolled diabetes, starvation or certain alcoholic conditions.
Dietary ketones are more common than most people realize. As well as being caused by low-carbohydrate eating, they will occur as a result of any weight-loss plan when fat is burned or even after an overnight fast.
Ketones and Evolution
Ketones are produced when fat is utilized to meet energy needs. This happens when the diet comprises less than approximately 50 grams of carbohydrates per day. Ketones are a source of energy for the heart muscle and a backup fuel source for the brain. It is because of our bodies’ ability to utilize stored fat in times of a limited food supply that the human species has survived. This ability to safely use ketones preserves lean body mass while providing fuel for the brain.
Ketoacidosis or Dietary Ketones
Diabetic ketoacidosis occurs when blood glucose levels are exceedingly high because insulin levels are too low. The inability of the body to handle such high levels of glucose leads to a large production of acid compounds that the body is unable to neutralize. Dehydration occurs as the body loses large amounts of water through the urine attempting to remove excess glucose. This combination of circumstances leads to a life-threatening acidosis.
To clear up the misconception and confusion common among many people (including the medical profession), one does not get acidosis simply by having ketones from controlling carbs. Note that one can be burning fat without excreting ketones in the urine. The excess ketones not used for energy are excreted.