How to Fast for a Day

Co-authored by Kristi Major

Last Updated: September 3, 2020 References Approved

Fasting is the act of intentionally refraining from eating for a period of time. Some people fast to diet and lose weight, while others fast for religious or spiritual clarity. Intent is the key here: fasting goes against your body's natural drive to feed itself, so you'll need to be clear about why you're doing this if you're going to stick to it. Before the fast, drink plenty of water, eat fruits and vegetables, and get plenty of sleep. You may find more clarity from the experience if you treat your body well before, during, and after.

Part 1

Part 1 of 3:

Setting an Intention

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Clarify your purpose in fasting. Ask yourself what you wish to learn from the experience, and use this purpose to set an intention for the day. You may find that you get much more out of the fast if there is a drive behind your discipline. Consider whether you have any goals for spiritual or mental development, or whether you are simply trying to tap into the physical benefits. Meditate on a theme, a question, or a goal.
- Fast to detoxify your system. Refraining from food for a day can help your body filter out toxins, solid obstructions, and other contaminants that weigh you down.
- Fast to reach a breakthrough. Perhaps you need to answer a problem, understand a situation, or come up with with an idea or insight. Fasting can put your mind into a simplifying state that makes it easier to frame your problems.^{[1]
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- Fast in conjunction with deep meditation, yoga, or sensory deprivation to explore the depths of your mind. Transcend the distractions of hunger with discipline and focus.^{[2]
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2
Define the beginning and end of your fast. Many traditional religious fasts only require you to refrain from eating until the sun goes down. If you're fasting for an Islamic rite, for instance, the fast begins about 1 and 1/2-2 hours before sunrise and you can eat after sunset. However, a full 24-hour fast has become a popular way to maintain health and vigor – particularly in yogic circles. The goal of a 24-hour fast is to not eat anything after your evening meal, and to refrain from eating until the next day's evening meal.

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Avoid fasting purely to lose weight. Fasting can help toxins exit your body, and it can help you digest food more efficiently – especially if you make it a habit. However, fasting will not necessarily help you lose weight. If you fast all day, but then gorge yourself on a large, carbohydrate-heavy meal, your metabolism won't kick into gear until after the meal. You won't actually burn more fat than you would if you weren't fasting.
- If you are only trying to lose weight, try consuming a very small amount of calories in the morning rather than fasting outright. This morsel will activate your metabolism so that your stomach feeds on stored fats.
- Consider doing a one-day juice-only fast once a week. With a juice diet, you can supply your body with enough nutrients that you don't have to deplete the sugar stores in your liver and muscles. This way, you'll detox without breaking down muscle tissue.^{[3]
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Make fasting a practice. Consider fasting for 24 hours around once a month. Some research suggests that performing a 24-hour fast can improve cardiovascular health and memory.^{[4]
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Expert Source

Kristi Major
ACE Certified Personal Trainer
Expert Interview. 28 October 2019.} Most evidence of this is still observational or based on animal studies, though, and regular fasting should not be attempted if you have or have had an eating disorder or difficulty regulating your blood sugar.
- It's possible regular fasting may improve your body's ability to metabolize sugar and decrease your LDL cholesterol, thereby improving your heart health.
- Always talk to your doctor before starting a regular fasting routine.

Part 2

Part 2 of 3:

Preparing to Fast

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Drink at least 2 liters (0.5 US gal) of water the day before the fast. Water helps balance the bodily fluids that aid the digestion, absorption, and transportation of nutrients; the circulation of blood; the production of saliva; and the maintenance of body temperature. This doesn't mean that you should chug a ton of water immediately before the fast. All this will do is make you urinate a lot a couple of hours later. Instead, increase your water intake beginning 72 hours before the fast.^{[5]
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- Juice, milk, tea, Gatorade, and other hydrating drinks will also help you prepare for your fast. Try eating a lot of water-heavy foods, particularly fruits and vegetables.
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Eat well and nourish your body the day before you fast. Don't overeat! Indeed, try to eat smaller portions than you usually would. If possible, eat primarily fruits and vegetables to balance your system. Foods that are rich in nutrients and full of water will help your body prepare for fasting. Avoid baked goods, especially those that contain a lot of salt and sugar.
- Avoid eating sugary, highly-processed foods the day before you fast. Your body will not function properly if it's running predominantly on sugar. Furthermore, processed foods may take longer to leave your system, making it more difficult to have a "clean" fast.
- If you are diabetic, consult with your doctor before consuming a lot of fruit.
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Get plenty of sleep the night before you fast. Your body won't be running on its usual caloric fuel, and you won't be able to push through tiredness with a burst of food-energy. If you give yourself a baseline of rest, it will be much easier to function throughout the day – and you may get more out of your fast.

Part 3

Part 3 of 3:

Fasting

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Focus on your intention. Fix your attention on the themes or questions that you want to answer. Focus on examining yourself, exploring an idea, touching base with your spirituality, or simply losing yourself in a state of channeled discipline. If your intention is to detoxify your system, use this purpose to hold yourself resolute against the supplications of hunger.
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Stay hydrated, if you are performing a water-only fast.^{[6]
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Expert Source

Kristi Major
ACE Certified Personal Trainer
Expert Interview. 28 October 2019.} Drink at least half a liter of water every two hours. Water will fill your stomach, restore your energy, and dilute the stomach acids that make you feel hungry. However, don't drink so much water that you feel sick.^{[7]
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- Some practices, such as traditional Islamic fasting, forbid you from drinking water between sunrise and sundown. In this case, it is incredibly important that you nourish your system with water before and after the fast.
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Keep yourself busy. Inactivity and boredom can lead you to thoughts of eating. Instead, occupy yourself with something that is engrossing, but not physically taxing.^{[8]
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Expert Source

Kristi Major
ACE Certified Personal Trainer
Expert Interview. 28 October 2019.} Reading, writing, meditating, slow yoga movements, working on your computer, walking in the woods, watching television, and driving short distances are all good ways to occupy yourself during a fast. Avoid high-energy activities like heavy exercises, going to the gym, lifting heavy weights, or running long distances: serious exertion will burn a lot of calories and make you unnecessarily hungry.^{[9]
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- Avoid thinking about food. Try not to spend time around food, pictures of food, or food smells.
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Stay strong. If you have the sudden urge to give up, remind yourself why you're doing this fast. Exercise discipline. Assure yourself that your hunger will not last forever. And besides: if you remain strong now, the rewards may be far greater than if you give in.
- Towards the end of the fast, you will likely feel strained and exhausted. This is where you'll need to bring out the reserves. Nap, if possible, or let visual media take over your brain. An absorptive action movie or video game can work wonders in this situation.
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Break your fast at the time you've designated. Take it slow, and be very mindful of how much you eat. Half your portions: it is absolutely imperative that you don't eat as much as you would regularly eat at mealtimes. Your digestive system is on low-power mode, and it isn't able to handle a massive burger right now. Instead, eat light foods like fruits, vegetables, and soup. Water and fruit juices are also important.
- Remember not to eat and drink too much, too quickly. Have an apple and a glass of water first, and wait ten minutes. Then, have a bowl of soup with a glass of orange juice.
- Space the process over 30 minutes to an hour. Eating a ton right away can land you in the bathroom for a long time accompanied by considerable pain – and it can even be hazardous to your health. Take it slow.

Warnings

If you begin to feel weak and fatigued, stop fasting. This could be a sign of poor health, or that you haven't appropriately prepared yourself for this fast.

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Avoid fasting if you are pregnant, sick, or taking medication. Your immune system is already more fragile, so depriving yourself of nutrition may actually slow your recovery.

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