Join our supportive Intermittent Fasting Community
Close this search box.

72 Hour Fast Guide – Amazing Benefits and Dangers to be Aware Of

Quick Navigation
How Fasting Works | An Hourly Breakdown of 72 Hour Fast | 72 Hour Fast Benefits | 72 Hour Fast Tips & Precautions

What is a 72 hour Fast? In short, a 72 Hour fast is not consuming food or calories for a period of 72 hours or 3 days. At the end of the 72 extended fasting window, you may resume eating as usual. But what are the benefits? Is it good or bad for your health?

In this age of modern technology, human beings live abundant and efficient lives. Scientists and innovators have perfected different agricultural methods throughout the years, resulting in a plentitude of food crops. Similarly, modern technology and gadgets have made human life easier and more efficient.

Although these technological advances are significant for humanity, they have also led to many health problems. Obesity has been the malady of the 21st century, with more and more people being affected by this health problem. What makes obesity so dangerous is that it is often the precursor to many life-threatening diseases like type 2 diabetes, coronary heart disease, stroke, and even cancer.

Modern doctors believe that fasting can be a potent tool against obesity and can help people lose not only body weight but also lead healthy lives. There are a lot of different kinds of fasting plans available that claim to be the best and most effective, namely, 24-hour intermittent fasting, 48-hour fasting, alternate-day fasting, etc.

In this article, we are going to discuss the very popular 72-hour fast and break down the benefits associated with it. We also aim to list the different precautions one needs to take before following this fasting plan so that our readers can get a complete picture of this popular plan and decide if it is right for them.    

72 hour fast

How Fasting Works? 

For many people, fasting might seem like an extreme step to take to lose weight, but honestly, fasting is logistically not that difficult when it is broken down. Hence, explaining how fasting works and what goes on in the body while fasting is better. In general, fasting is voluntarily avoiding food intake for a predetermined duration. The duration of the period generally depends on the type of fast. Most popular intermittent fasting plans require people to fast for 16 hours, 48 hours, or 72 hours.

To better understand how intermittent fasting works, we need to understand what happens in the body when we consume food. In general, when we consume solid food, our digestive system starts to break it down and eventually convert it to glucose, which is the primary fuel for our body. During this entire process, our body secretes many different hormones, namely insulin, ghrelin, etc., which help regulate this whole process.

The glucose produced by the body is generally used completely to perform daily activities and maintain ‘homeostasis’. When an excess of blood glucose levels are produced, our body converts it into glycogen and stores it in the liver for future use. This is further converted into fat and stored in the different fat reserves of the body.

When we fast, our body is deprived of the constant supply of glucose; this is when the body starts using the stored glycogen. When the fasting duration is extended (72 hours), this glycogen supply is insufficient, so the body is forced to tap into its different fat reserves. The body breaks down the fat molecules to produce energy to perform tasks and maintain ‘homeostasis.’ This process is known as ketosis and is considered the most effective way to burn fat and lose weight.      

72 Hour Fast

72 Hour Fast- An Hourly Breakdown 

During a 72-hour fast, our body undergoes changes; many specific hormonal and metabolic activities occur. Let us look at the different hourly happenings in the body during a 72-hour fast.

The Initial 24 Hours

During the initial 24 hours of a 72 hour fast, our body is still in the anabolic stage. The body mostly works to break down the last meal consumed just before the fast; hence, our digestive system is in overdrive mode. Regarding hormonal activity, three major hormones are active during this process: insulin, ghrelin, and leptin.

The insulin levels are generally heightened during this time as the insulin hormone regulates the digestive process. Similarly, ghrelin levels start to subside during the initial 24 hours, as ghrelin is responsible for making us feel hungry. Leptin levels, responsible for weight regulation, also subside dramatically as we move further into the fast. Fasting will improve your insulin sensitivity.

48 hours into the Fast

As we move past the 24-hour fasting duration, the body’s stored glycogen levels are depleted, requiring more fuel to maintain homeostasis. During this time, we might feel a bit hungry as the body craves more food to perform daily tasks. As we move further into the 48-hour mark, the body starts to look for other avenues for fuel, which is when it is forced to break down fat from the different fat resources. This process is known as ketosis.

During the later part of the 48-hour fast, the ketosis process is accelerated, and the body starts to naturally burn fat for fuel, leading to rapid fat loss. This benefit can also be experienced in the popular 48-hour fast plan.

The Final 72 Hours

Now that the body is in the final 72-hour fasting stage, some interesting things occur in the body. For instance, the ketosis process is now stabilized, meaning the body is breaking down fat and producing ketone bodies at a much more stable rate. The ketone bodies in the bloodstream act as fuel for the brain, which might give us a boost in cognitive health and mental clarity.

On a cellular level, during a 72-hour fast, the cells of our body start to consume other weak and diseased cells and cell organelles; this process is known as autophagy. Cellular autophagy is regenerative, meaning the eaten cells are replaced by newer, healthier cells.

72 Hour Fast

What are the Benefits of a 72-hour fast?

Let us look at the different study-based 72 hour fast benefits.

72 hour fast benefits

Weight Loss

One of the primary benefits of 72 hours fasting is weight loss, which is achieved by fat burning. The constant ketosis process that the body is forced to undergo while fasting is a great way to target the visceral fat reserves of the body. Weight loss is also related to calorie restriction, and fasting can be a great way to consume fewer calories throughout the day, which eventually helps in weight loss.  You will enter fat-burning mode in this type of fast pretty quickly, so if you do workout, allow yourself enough recovery time in this fasting protocol, as you may feel a bit weak on an empty stomach. Fasting is an amazing way to lower body fat!

Improves Insulin Resistance

Insulin, produced by the pancreas, is an important hormone in our body. It is responsible for our body’s overall blood sugar levels and is vital for digestion and assimilation.

Constant snacking throughout the day can cause several irregular insulin spikes, which with time, can lead to insulin resistance, often causing type 2 diabetes. Fasting can help prevent these irregular insulin spikes, which can help the body better process insulin spikes, improve overall insulin resistance, and prevent diabetes

May Improve Heart Health

fasting for 72 hours

Fasting does not directly affect the human heart, but it does improve the different health markers responsible for good heart health. These include blood pressure, blood sugar, triglyceride levels, etc. Additionally, some studies suggest that intermittent fasting can help lower the bad LDL cholesterol, which can be the main reason for coronary heart disease and even stroke. 

Reduce Inflammation

Inflammation is generally not bad, as it is the body’s defense mechanism against chronic diseases and infections. But it has been proven that having high levels of inflammation can be bad for the body as it causes oxidative stress. Fasting for longer durations can help flush out the free radicals, which are often responsible for heightened inflammation. This chronic inflammation can wreak havoc on your body over a long time. So fasting carries an important role in the recovery from this excess inflammation.

Helps your Immune system function properly

The longer you fast, the more your body is able to use its internal processes to help your body function more optimally. This has a huge benefit to your immune system. As you immune cells are able to fight viruses, bacteria and other invaders better. The fasting window allows you to use that energy for battle inside your body. It may also fight cancer cells and other medical conditions as shown in various animal studies. The human body is a complex mechanism, and the process of digesting food can be very exhausting and taxing, especially when eating processed foods, and other inflammatory foods. But giving your body the rest it needs, especially with a long fast, will allow your body enough time to have a huge recovery from cellular damage that has been done. This allows the natural repair process of the body enough time to activate.

May Slow Down The Aging Process

Some preliminary studies have pointed out that fasting for multiple days can help slow down our aging process. This is directly linked to the cellular autophagy caused by fasting. In this process, the body’s healthy cells consume the weak and diseased cells and cell organelles. These are eventually replaced by younger, healthier cells, contributing to the overall aging process and increasing lifespan. With increases in human growth hormone, longer fasts tend to increase this HGH in your body. Another study at MIT revealed when a subject was in a fasted state, the stem cells extracted after the fasting period showed a double in their regenerative capacity, meaning the stem cells could proliferate in higher numbers with greater efficiency.

72 Hour Fast: Tips & Precautions 

Now that we have discussed all the benefits and workings related to the 72-hour fasting process, It is also important to point out some precautions and tips for performing a 72-hour fast safely.

  • Fasting for 72 hours can be highly stressful for the body and should never be done by people new to fasting. People can start with the easier 16/8 fast period and slowly build up to the 72-hour fast.
  • A 72-hour fast is not a dry fast; hence, it is crucial to stay hydrated throughout the fasting duration. People can consume zero-calorie electrolyte drinks to replenish the electrolytes lost during fasting. Additionally, people must consume adequate water to stay hydrated during the fast. This is considered water fasting.
  • 72 hours of fasting can cause severe hunger pangs. People can consume zero-calorie drinks like black coffee and herbal teas to get through this. These can uplift your mood and cause your hunger to subside.
  • Your Energy levels may be low at the beginning on the first day, but know that your body is helping itself. It’s a good idea to supplement with electrolytes if possible.
  • Older adults, young kids, pregnant women, or people with some preexisting health conditions must stay away from fasting, as it can cause severe health complications.
  • You may consume drinks like green tea, water, black coffee if you choose, but be careful of drinks like bone broth, milk, sugary drinks, and other calorie containing drinks, as they MAY break your fast if you consume them.
  • To make sure you are getting enough nutrients, I highly recommend MegaFood Supplements, click the link here to see what they offer. They are easily digestible, and are natural so no synthetic vitamins/minerals, and can be taken on an empty stomach during a fast, and will NOT break your fast with most of their products.
  • There are several varieties that you can also implement while fasting for 72 hours. You can do a 72 hour fruit fast or fruit cleanse. But keep in mind, that eating calories may stop the cellular repair that you would get from 72 hrs water fasting.

Conclusion – Fasting for 72 hours

I personally tried the 72 hour fast on one occasion, I did feel by day 3 I wanted to eat, and I workout quite a bit, so to get the energy I needed it wasn’t for me. But a 48 fast may be more your type if this is too long, or even 24 hours. Feel your body, listen to your body, and know when it is time to stop. Drink water, electrolytes and take it slowly!

The 72-hour fasting plan has several health benefits associated with it. It can be a fantastic way to deal with obesity and prevent the health complications caused by obesity.

But it must also be said that a 72-hour fasting routine is challenging to follow and should only be attempted by people comfortable with fasting. For people new to fasting, other more manageable intermittent fasting plans have similar benefits and are easier to follow.

The benefits of 72 hour water fast routine can be amazing! But don’t do it too often, maybe once a month to allow your body to repair, and get back into your normal eating routine as to not lose muscle mass, etc. Always proceed with caution! And play it safe.

Like any type of fasting be sure to do this under medical supervision, to ensure this is the best way to manage your health goals and/or issues. Side effects while in this fasted state are minimal typically, but extended fasts are not for everyone. Do not make this part of your normal routine, as a 3-day fast is intended to be spread out between longer stretches of normal eating. You will not lose muscle mass since the period of time is short-lived. When you break your 72 hour fast, go for healthy fats, such as Avocado, salmon, steak, etc.. And like anything, use this diet along with a healthy lifestyle overall, and you will see a significant increase in your well-being and quality of life going forward.

Need help on your fasting journey?

Also need help fasting? Check out the Best Intermittent Fasting Mobile Apps we recommend to help you on your journey.

Need Help choosing food and meals while intermittent fasting, try one of our Intermittent Fasting Meal Plans, you can choose based on your diet. Various options based on your caloric intake needs.

Leave a Reply

Your email address will not be published. Required fields are marked *

More on Intermittent Fasting

About the author