The ketogenic diet, colloquially called the ketogenic diet, is a popular diet that contains high amounts of fat, adequate protein, and low carbohydrate content. It is also known as a low-carbohydrate, high-fat (LCHF) diet and a low-carbohydrate diet.
Ketogenic diets are basically designed to induce a state of ketosis in the body. When the amount of glucose in the body is too low, the body switches to fat as an alternative source of energy.
The body has two primary fuel sources which are:
-
glucose
-
free fatty acids (FFA) and, to a lesser extent, ketones made from FFA
Fat deposits are stored in the form of triglycerides. They normally break down into long chain fatty acids and glycerol. The removal of glycerol from the triglyceride molecule allows the release of the three free fatty acid (FFA) molecules into the bloodstream for use as energy.
The glycerol molecule enters the liver where three molecules combine to form a glucose molecule. Therefore, as your body burns fat, it also produces glucose as a by-product. This glucose can be used to fuel parts of the brain and other parts of the body that cannot function with FFA.
However, while glucose can travel through the bloodstream on its own, cholesterol and triglycerides need a carrier to move through the bloodstream. Cholesterol and triglycerides are packed into a transporter called low-density lipoprotein, or LDL. Therefore, the larger the LDL particle, the more triglycerides it contains.
The general process of burning fat deposits for energy produces carbon dioxide, water, and compounds called ketones.
Ketones are produced by the liver from free fatty acids. They are composed of 2 groups of atoms linked together by a carbonyl functional group.
The body has no capacity to store ketones and therefore they must be used or excreted. The body excretes them through the breath as acetone or through the urine as acetoacetate.
The cells of the body can use ketones as a source of energy. Additionally, the brain can use ketones to generate about 70-75% of its energy requirement.
Like alcohol, ketones take priority as a fuel source over carbohydrates. This implies that when they are high in the bloodstream, they must be burned first before glucose can be used for fuel.
What Causes Ketosis?
When you start eating fewer amounts of carbohydrates, your body gets a smaller supply of glucose to use for energy than before.
The decrease in the amount of carbohydrates consumed and the subsequent reduction in the amount of glucose available slowly forces the body into ketosis. Therefore, the body enters a state of ketosis when there is not enough glucose available for the cells of the body.
Starvation-induced ketosis
The fasting and starving states generally involve little or no intake of food that the body can digest and convert to glucose. While starvation is involuntary, fasting is a more conscious choice to not eat intentionally.
However, the body goes into “starvation mode” every time it sleeps, skips a meal, or intentionally fasts. Lack of food intake causes a reduction in blood glucose levels. As a result, the body begins to break down stores of glycogen (stored glucose) for energy.
The glycogen is converted back to glucose and used by the body for energy. In this state, the body also begins to burn stored fats. Therefore, the production of ketone bodies (ketogenesis) is induced by the lack of available glucose.
As long as the amount of ketones in the blood outnumbers the glucose molecules, the cells of the body will begin to use the ketones for energy.
