Eat a very small amount of food before fasting
The 5:2 or 6:2 intermittent fasting patterns only you to consume only 25% of your daily calorie requirements. However, if you want to switch to full-fledged fasting, eating a small amount of food before fasting and midway might be the best option instead of filling your tummy with empty calories.
Eating small amounts throughout the day might decrease the risks associated with fasting, such as dizziness, fatigue, and hunger. Sustainable and healthy eating is the key to keep hunger at bay during fasts.
Stay hydrated
Mild dehydration during a fast can cause a dry mouth, fatigue, headache, nausea, and thirst. That’s why it is vital for you to drink as much water as you can. Most health experts recommend following the 8*8 rule. It means that you have to drink 8 liters of water every day.
You get 30% of your fluids from food. Since you are not eating that, it’s best to compensate for it by drinking water. Otherwise, it’s easy to be dehydrated and make yourself sick to the stomach. 
Keep the duration short
The duration of fast is totally up to you and let me tell you, there’s no single way to fast. There are popular fasting regimens that you can follow, such as the 6:1 intermittent fasting pattern, the 5:2 pattern, the 16:8 pattern and the eat, stop, eat pattern.
I usually switch between the 5:2 pattern and the 16:8 pattern. In the 5:2 pattern, I restrict my calorie intake for 2 days and eat a healthy diet for 5 days straight.
Similarly, I allow myself to eat in the 8-hour window and then fast for 16 hours thrice a week.
