A ketogenic diet is not simply a diet that you can choose to go on and off of at any point. It takes little time for your body to adjust and go into a state known as ketosis.
This process? Anywhere from 2 – 7 days, depending on your body type, activity levels, and what you’re eating. The fastest way to get into ketosis is to exercise on an empty stomach, restrict your carbohydrate intake to 20g or less per day, and be vigilant with your water intake.
To improve the rate at which you enter ketosis, there is a method called Fat Fasting.