...is an increasingly popular eating pattern that involves not eating or sharply restricting your food intake for certain periods of time. It may boost your health. However, fasting can be dangerous if not done properly.
Longer periods of fasting increase your risk of side effects, such as dehydration, dizziness, and fainting.
The best way to avoid these side effects is to stick to shorter fasting periods of up to 24 hours — especially when you’re just starting out.
Eating a small amount on fast days rather than cutting out all food may reduce your risk of side effects and help keep hunger at bay.
If you want to try fasting, restricting your calories so that you still eat small amounts on your fast days may be a safer option than doing a full-blown fast.
Mild dehydration can result in fatigue, dry mouth, thirst and headaches — so it’s vital to drink enough fluid on a fast.
During a fast, many people aim to drink 8.5–13 cups (2–3 liters) of water over the course of the day. However, your thirst should tell you when you need to drink more, so listen to your body.
...such as walking or meditating, may make your fast days easier.
Avoiding eating on fast days can be difficult, especially if you are feeling bored and hungry. One way to avoid unintentionally breaking your fast is to keep busy.
You may feel a little tired or irritable during your fast, but if you start to feel unwell, you should stop fasting immediately.
Some signs that you should stop your fast and seek medical help include tiredness or weakness that prevents you from carrying out daily tasks, as well as unexpected feelings of sickness and discomfort.
If you’re new to fasting, it’s best to keep any exercise to a low intensity — especially at first — so you can see how you manage.
Low-intensity exercises could include walking, mild yoga, gentle stretching, and housework.
The following shouldn’t attempt to fast without consulting a doctor:
The process by which the cell devours itself.
...is the voluntary withholding of food for spiritual, health, or other reasons.
Food is easily available, but you choose not to eat it. This can be for any period of time, from a few hours up to a few days or – with medical supervision – even weeks on end.
It’s done by someone who is not underweight and thus has enough stored body fat to live off.