Keto diets simulate prolonged fasting. Because of this effect, fat is used as the body's main energy source. The lack of carbohydrates (namely, glucose) stimulates ketogenesis, or the mass production of three ketonic bodies: acetone, acetoacetate, and β-hydroxybutyrate. When you consume carbohydrates, whether simple or complex, the body leaves the ketosis state (1, 4).
Ketonic bodies become the raw fuel source for the brain, heart, and muscles (4).
In people with certain medical conditions, neurons cannot use glucose as an energy source, which leads to seizures. In these cases, ketonic bodies provide energy and reduce the disease's symptoms. On the other hand, many people follow a keto diet for weight loss because ketonic bodies have appetite-suppressing effects (1, 5).