Ketogenic Diet Facts: How Long Will It Take To Enter Ketosis?

Entering ketosis, a metabolic state where a human body metabolizes fat at a high rate and converts fatty acids into ketones, takes patience and willpower. And once this ideal state is achieved, it takes more patience and willpower to maintain it.

Ketosis is a nutritional process characterized by serum concentrations of ketones above 0.5 mmol along with low and stable levels of insulin and blood glucose.

The elevated level of ketones in the blood is a condition called hyperketonemia. Ketones or ketone bodies are formed by ketogenesis, which occurs when liver glycogen stores are depleted. The levels of ketones are regulated mainly by insulin and glucagon.

Ketones, a type of acid, are chemicals made in the liver. A human body produces them when it doesn’t have enough insulin to turn sugar or glucose into energy. The body needs another source of energy, so it uses fat instead. The liver turns this fat into ketones and sends them into your bloodstream.

Experts say the time it takes to enter ketosis varies from person to person. This process, on average, takes two to four days if a person eats only 20 to 50 grams of carbs per day. It might take some people a week or longer to reach this state given it demands a drastic revision of one’s normal lifestyle.

Factors that affect how long it takes to enter ketosis include a person’s typical daily carb intake, his daily fat and protein intake, exercise, his age and metabolism rate.

An individual who typically consumes a high-carb diet before starting a keto diet may take longer to enter ketosis compared to one who generally eats a low- to moderate-carb diet. This is because your body needs to deplete its glycogen stores before entering ketosis.

Some people take longer to enter ketosis by unintentionally eating more carbs than recommended for a ketogenic diet. Eating too much carbs can stop your body from producing ketones.

Another reason is not eating enough fat on a ketogenic diet. In general, people should aim to consume at least 70 percent of their daily calories from fat, 20 percent from protein and the remaining 10 percent from carbs.

Eating too much protein on a keto diet can also make it harder to enter ketosis. Too much protein will allow your body to use gluconeogenesis, which is a process that converts amino acids from protein into sugar. And we know too much sugar will stop your body from producing ketones.

As your body transitions into ketosis, you may experience several symptoms — sometimes known as the “keto flu.” These include headaches, fatigue, nausea, bad breath and increased thirst.

While these symptoms may give you an indication that your body is transitioning, the best way to tell whether you’re in ketosis is to test your body's ketone levels.