The ketogenic diet, often referred to as the keto diet, is a low-carbohydrate, high-fat diet that has gained popularity in recent years for its potential health benefits and weight loss effects. It involves reducing carbohydrate intake while increasing fat intake, which shifts the body's metabolism into a state called ketosis.

In a standard Western diet, the primary source of energy comes from carbohydrates. When you restrict carbohydrates significantly, the body starts using an alternative fuel source—ketones, which are produced from fats. This metabolic state of ketosis is characterized by elevated levels of ketones in the blood.

Here are some key principles of the ketogenic diet:

- Carbohydrate restriction: The keto diet typically involves reducing carbohydrate intake to around 20-50 grams per day, or about 5-10% of total calories. This restriction aims to deplete the body's glycogen stores and force it to rely on fat for energy.

- High fat intake: The majority of calories in a ketogenic diet come from fat sources such as avocados, nuts, seeds, olive oil, coconut oil, butter, and fatty cuts of meat. Fat intake typically accounts for about 70-75% of total calories.

- Moderate protein intake: Protein intake is usually moderate and accounts for around 20-25% of total calories. It is important not to consume excessive protein, as it can potentially be converted into glucose through a process called gluconeogenesis, which may hinder the state of ketosis.

- Ketosis and fat adaptation: By following a ketogenic diet, the body gradually adapts to using fat as its primary fuel source. This shift in metabolism can take several days to weeks, and during this time, some people may experience symptoms known as the "keto flu," including fatigue, headaches, and irritability.