<div>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. </div>

Stay hydrated

...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.

Keeping busy with low-intensity activities

<ul><li>The 5:2 Pattern: restrict your calorie intake for two days per week (500 calories per day for women and 600 for men). </li><li>The 6:1 Pattern: similar to the 5:2, but there’s only one day of reduced calorie intake instead of two.</li><li>“Eat Stop Eat”: a 24-hour complete fast, 1–2 times per week.</li><li>The 16:8 Pattern: only consuming food in an eight-hour window and fasting for 16 hours a day, every day of the week.</li></ul>

Popular regimens of fasting:

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.

Eat a small amount on fast days

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.

Stop fasting if you feel unwell

<ul><li>Eat enough protein: Having enough protein during your fast may help minimize muscle loss and keep your appetite in check.</li><li>Eat plenty of whole foods on non-fasting days: This may improve your health and keep you well during a fast.</li></ul>

Healthy eating

The following shouldn’t attempt to fast without consulting a doctor:<ul><li>People with a medical condition like heart disease or type 2 diabetes</li><li>Women who are trying to conceive</li><li>Women who are pregnant or breastfeeding</li><li>People who are underweight</li><li>Those who have experienced an eating disorder</li><li>People who have problems with blood sugar regulation</li><li>People with low blood pressure</li><li>Those who are taking prescription medications</li><li>Woman with a history of amenorrhea</li><li>Older adults</li><li>Adolescents</li></ul>

Fasting isn’t for everyone

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.

Keep exercise mild

...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.

Intermittent fasting...

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.

Keep fasting periods short

There are many different ways to fast. Intermittent fasting is an increasingly popular eating pattern which involves not eating or sharply restricting your food intake for certain periods of time. This fasting method has been linked to a range of potential health benefits, including short-term increases in human growth hormone (HGH) and changes to gene expression (, , , ).