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Home Fasting 3-Day Fast: 5 Tips for Completing a Successful Fast

3-Day Fast: 5 Tips for Completing a Successful Fast

3 day fast

Intermittent fasting and fast-mimicking diets have exploded in the health and wellness space. It has some fantastic weight loss benefits, along with other advantages for your health.

A 3-day fast is a form of prolonged fasting and is at the more challenging end of the intermittent fasting spectrum. So, how does a 3-day fast work, and what are the benefits?

What Is a 3-Day Fast?

A 3-day fast, a form of prolonged fasting, is exactly as it sounds – 3 days of fasting. During the 72-hour fasting period, you may only consume water and herbal teas.

This length of fast is not recommended more than 1 every 3 months. While fasting has many benefits, long fasts can lead to complications, including muscular cramps, sleep disturbances, and headaches, if done too frequently. 

You could try mixing 3 days of fasting with your normal diet or with another intermittent fasting pattern to get all the benefits in a safe way.

How to Fast for 3 Days? An Extended 5-Step Guide

There are a few steps you should go through before and during a period of prolonged fasting. These are explored in-depth below to help you out.

#1 Consult with your doctor

72 hours without food is going to be hard on your body, so it is always advisable to consult with your doctor first. 

Consult with your doctor


There may be certain factors that put you in a high-risk category, and your doctor can explain them and advise you to avoid this type of fasting period if it is necessary. Risk factors include those who have diabetes, as it may cause dangerous fluctuations in blood sugar levels, and anyone who is already underweight.

If you’re not high-risk, it is still a good idea to speak with a doctor. A doctor can give you pointers and help you to make sure that you’re fasting in a safe way. Fasting is considered safe, but you may be more suited to a 24-hour or 36-hour fast rather than a 72-hour fast.

#2 Prepare your body for the fast

Intermittent fasting can be incredibly challenging. To make the most of fasting, you should prepare your body before you begin. This means trying shorter fasts and building up to an extended fasting period.

You could begin with other types of intermittent fasting, like a 12-hour fast or the 14:10 method of fasting. All of these methods are good for weight loss, too. Getting your body used to extended periods without food can help to reduce side effects, such as headaches, extreme hunger, and irritability.

#3 Drink enough water

You need to ensure you drink enough water so you don’t get dehydrated while fasting. We get a lot of water from the food we eat, so when you’re limiting your food intake, you may feel thirstier than usual.

Drink enough water

Try increasing your fluid intake by drinking more water and zero-calorie beverages.

#4 Don’t exercise

Unfortunately, a long period without food means exercise should not be attempted.You should avoid any kind of endurance training as you’re at higher risk of fluid loss and electrolyte imbalances.

It is best to exercise only after you’ve completed your 3-day fast.

#5 Know when to stop

Even if you have tried another form of fasting, there is a vast difference between fasting for 14-, 16-, or 18-hour periods and fasting for 3 whole days. This means you must know when to stop and not push yourself too far.

Not eating for 3 days can be dangerous, and if you feel excessively tired, nauseous, and sick, you need to stop fasting and reintroduce food as soon as possible. If you fast for too long, you could end up severely dehydrated, develop an electrolyte imbalance, or feel faint and tired. In extreme cases, lack of food can lead to organ failure and heart problems.

Long fasting periods like this are often supervised by a health professional to ensure you stay safe.

5 Extraordinary Benefits of a 3-day Fast

While there are dangers and risks of fasting for 3 days, there are also many benefits to limiting your food intake. Indeed, the benefits of a 72-hour fast have been summarized below to help you better understand how this kind of extended fasting could benefit you.

#1 Weight loss

The most well-known benefit of the 3-day fast is the way it supports people to lose weight. Intermittent fasting is often used by those looking to reduce their weight and many people have had success losing weight from this method.

In fact, studies suggest that fasting may be more beneficial in reducing body fat, particularly belly fat, than continuous calorie restriction.

#2 Better skin

There may be a link between long periods of fasting and good skin health. Research has found it may benefit many skin conditions, including acne, inflammatory conditions, and even skin cancer. 

Better skin

More research is still required to fully determine the link between skin health and fasting.

#3 Autophagy

Autophagy is the process in which old cells are recycled, renewed, and removed from the body. As we age, autophagy is thought to slow down, and the reduction of this process can be linked to a number of age-related diseases, including neurodegenerative diseases like Alzheimer’s.

Extended fasting has been found to boost autophagy which has also been linked to extended lifespans.

#4 Immunity boost

Studies show that fasting can reduce inflammation. While acute inflammation is an immune response that serves our bodies well, chronic inflammation can be linked to a number of diseases and can have a detrimental effect on your health.

Additionally, fasting is thought to “reboot” your immune system by triggering stem cell regeneration.

#5 Hormone balance

Human growth hormone (HGH) is vital for your health and contributes greatly to metabolism, weight loss, and muscle growth. Fasting is thought to trigger an increase in the production of HGH. Indeed, a study found a significant increase in HGH after 24 hours of fasting.

How to Break a 3-Day Fast?

It is important not to shock the digestive system after 3 days of fasting, which means you need to ease your body back into a healthy diet. You also need to avoid binge eating, even if it can be tempting after 3 days without food.

It is recommended that your first meal after a 3-day fast is something like soup, a  smoothie, or bone broth. Heavier foods may cause digestive discomfort as your body hasn’t been breaking down food for 3 days.

Next, you could move on to soft-boiled vegetables, like spinach, broccoli, and cauliflower along with eggs, Greek yogurt, and lean protein, like skinless chicken breast. Once you have managed lighter foods, you can then reintroduce more protein, healthy fats, complex carbohydrates, and more.

It is very important to move slowly through this stage of a 3-day fast. Don’t try to eat too much at once, and go easy on your gut.

What Are the Health Risks of a 3-Day Fast?

A 3-day water fast is a great way to burn fat and improve your overall health, but there are health risks that come along with not eating for 3 full days. These include:

  • Dehydration
  • Nausea
  • Digestive discomfort
  • Irritability
  • Excessive hunger and thirst
  • Electrolyte imbalance
  • Fatigue
  • Low energy
  • Dizziness
  • Headaches
  • Muscle loss
  • Metabolic changes

Who Can’t Do a 3-Day Fast?

Even though it has a ton of benefits, there are people who should not try a 3-day water fast. These include:

  • Pregnant women
  • People who are breastfeeding
  • Those with type 1 diabetes
  • Anyone under the age of 18
  • Anyone who has a history of eating disorders
  • People taking medication for blood pressure or heart disease
  • Anyone else with a condition that could be exacerbated by prolonged periods without food

Remember to consult a doctor before you try any new eating plan to ensure that it is safe for you. If you ever feel ill while fasting, stop immediately.


How much weight will I lose on a 3-day water fast?

During one 3-day fast, you are unlikely to notice significant changes in your weight. While you may notice weight loss on the scales, it is likely water weight, and you will regain it when you begin eating again.

Is it safe to fast for 3 days?

Generally, it is considered safe to fast for 3 days, but only if the person has no health issues. You should seek medical advice before trying a 3-day fast and ensure that you remain hydrated throughout.

What happens when you fast for 3 days?

Fasting for 3 days can result in weight loss and may have benefits for your immune system, skin, and longevity. However, it could also lead to fatigue and exhaustion, headaches, and electrolyte imbalance.

What can you drink during a 3-day fast?

During a 3-day water fast, you can only drink water. However, some people also drink zero-calorie beverages like unsweetened green tea, coffee, and black tea.

A Word From MD

Prolonged fasting has benefits for lots of aspects of health, including blood pressure, blood sugar regulation, longevity, neurodegeneration, and weight loss. However, it can also have dangerous consequences if done too often or in an unsafe way.

If you’re thinking of trying a 3-day prolonged fast, then you need to prepare your body by practicing shorter fasts first. You should also ensure you stay hydrated by consuming water and zero-calorie drinks, like green tea, and you should always stop fasting if you begin to feel unwell.

Longer fasts that last more than 24 hours are not advisable more than 1 or 2 times per month. If you want an intermittent fasting schedule that can be done continuously, opt for methods like 16:8 or 20:4.


Three days of fasting can be incredibly hard on the body. While it can contribute to considerable weight loss, it can also cause many adverse side effects. Make sure you are totally prepared before undertaking a fast this long, and always seek medical advice before doing so.

Written by
Anahit Harutyunyan, MD

Anahit Harutyunyan is an MD in Anaesthesiology and Intensive Care. She also has a second specialty as a Medical specialist in Physiatry. Anahit has work experience in different clinics as ICU Doctor and Medical Doctor in Yerevan and Gyumri Ambulance Stations. She also worked in the therapeutic department during covid and has morning consultations in Nor Med private clinic.

3 day fast

Comments (2)

  1. avatar
    Veronica Skuriat
    4 Dec, 2023 at 8:58 am

    Impressive introduction to longer fast regime, thanks to those who have prepared this, demonstrates professional attention to detail.

  2. avatar
    4 Jul, 2023 at 5:49 am

    woah quite informative


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