Blog Diets Fasting 2 Day Fast Benefits And Risks

2 Day Fast Benefits And Risks

For some of us, not eating for a prolonged period seems unhealthy and unnatural. 

Yet, hunter-gatherers in the past would not have agreed with us. They didn’t have a frequent supply of convenient food as we do today, as they were likely daily hunting for it. That said, fasting turned out to be a common situation for them. 

These days, most of us have access to food 24/7. While that may not be such a bad thing, we are more sedentary than ever, loading ourselves up with more calories we need. 

Why? Because we are continually tempted by quick possibilities to reach for food. We no longer need to hunt for it. Just think about it, if you want a cookie at 10 PM, you order it online, and wa-la the cookie is at your doormat within minutes. 

Even with the easy supply of daily meals, people are still attempting the deep fasting regimen. Amazingly, intermittent fasting offers crucial benefits, from normalized blood sugar levels to the shedding of calories. 

Today we’re going to focus on a severe type of fasting – 48 hour fast. Along with the 2-day-fast benefits and risks, you’ll uncover the main rules for this non-eating regime and the number of calories you will possibly burn after 48 hours of fasting. 

Is fasting for 2 days healthy?

Fasting for 2 days straight means abstaining from food for 48 hours. During this time you’re drinking only non-caloric beverages. 

To answer the question of whether it’s healthy or not, let’s begin with some scientifically-backed 48-hour fast benefits. 

According to one review from 2014, fasting might reduce the symptoms of obesity, asthma, hypertension, and rheumatoid arthritis (4).

Fasting for more than 24 hours is linked to lowered inflammation by reducing oxidative stress in the body’s cells (6). While temporary inflammation is an important immune response, chronic inflammation may put you at risk of adverse health consequences, such as cancer, heart disease, and rheumatoid arthritis (12).

See also
The Science Behind the Fasting Mimicking Diet

Other 2-day water fast benefits include improved insulin sensitivity and blood sugar levels. Insulin is the hormone that works in your body to move glucose from the blood into the cells where it is broken down for energy.

Studies suggest that various types of fasting might reduce insulin levels. The hope is that this is a sign of improved insulin sensitivity which helps your body to transport blood sugar more efficiently (5).

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Additionally, one review highlights the positive effects of intermittent fasting on

  • enhanced brain functioning
  • reduced blood pressure and heart rate
  • reduced markers of oxidative stress (5).

However, the majority of the data is still based on animal studies, from which we cannot draw conclusive interpretations for humans. 

Now the juiciest part – weight loss. When it comes to 2-day fast benefits, weight loss studies for 48 fast are lacking. What we do know is that a 48-hour fast represents a large calorie deficit in the diet, which can positively affect weight loss in some people. 

2-Day Fast Weight Loss is likely to be effective only when you don’t go over the number of calories in the next non-fasting days. Besides, a 48-hour fast should not be done more than 1-2 times per month. Some people should not fast at all – talk to your healthcare provider about whether it is safe for you. 

That being said, no fasting regime will be a silver bullet. Regular exercise and a balanced, nutritious diet are necessary to support a sustainable pace of weight loss.

See also
6 Dirty Fasting Mistakes You're Making That May Get In The Way of Weight Loss

Don’t expect the same benefits with a 2-day dry fast, as not eating for 48 hours is already challenging for your body. You need to be hydrated during the 2-day fasting period and consume enough non-caloric fluids to function.  

2 day fast benefits  

Is a 48-hour or 72-hour fast better?

48 and 72-hour fasts are both extreme fasting regimes. During the 72-hour fast, a person abstains from food for three days. 

During both fasts, your body enters a state of ketosis, where it starts to burn stored fat for energy instead of glucose from food (9). This process has been suggested to contribute to increased fat burning, enhanced insulin sensitivity, and potential benefits for type 2 diabetes and metabolic syndrome, however, the evidence is not conclusive and some studies suggest the opposite. 

Both 48 and 72-hour fasts come with health risks and should be discussed with your healthcare provider before attempting them. 

Beginners should not begin their fasting journey with such long-duration fasts. The most popular fasting regime for beginners is 16:8, where you fast for 16 hours each day and eat during an 8-hour window. 

Read more: 5 Chicken Alfredo Keto Recipes for Fast Dinners or Family Stunners Without Eating Too Many Carbs

Is 48 hours enough for autophagy?

Autophagy is the process where the body gets rid of parts of cells that are no longer functioning as they should. Autophagy allows the tissues to regenerate by recycling or disposing of damaged cell material (14).

One study states that fasting and calorie restriction are good ways to promote autophagy in the cells of the body (11). However, it is not known how long one needs to fast to get the most autophagy benefits while minimizing health risks. 

See also
48-Hour Fast: Is It Healthy? Benefits and Risks Explained

Why is day 2 of fasting the hardest?

The 48-hour fasting may be the hardest, in regard to its potential health risks and adverse effects. Among the possible drawbacks of intermittent fasting in general are: 

  • hunger and hunger pangs
  • gastrointestinal symptoms
  • dizziness
  • irritability
  • fatigue
  • nausea
  • insomnia
  • headaches
  • fainting (8).

Besides these, another study found that 48 hours of fasting resulted in reduced blood oxygen levels in weight lifters—which might negatively impact their workout performance (1).

With this in mind, you should start with minor fasts. 15/9 Intermittent Fasting, for example, is good for beginners. Then, slowly work your way up to a 48-hour fast if you and your healthcare provider decide that the potential benefits outweigh the risks. Taking smaller steps will help your body tune into the fasting regime healthily. 

Another thing to consider is that not everyone should follow the fasting regime. The kinds of individuals who need to avoid fasting are:

  1. People with diabetes who take insulin or on blood sugar-lowering medications;
  2. Pregnant and breastfeeding women;
  3. People who are underweight or have a history of an eating disorder (7);
  4. Individuals taking blood pressure medications and blood thinners. 
  5. Children and adolescents

2 day fast benefits  

How much weight will I lose if I do a 2-day fast?

Losing weight with a 48-hour fast is possible but not a guarantee. The 2-day fast once or twice per month may help you reduce your calorie intake by approximately 8.000 calories per month. If we convert those calories to pounds, here’s what we get – 2-day fast weight loss equals 8000 calories which is 2.285714 lb.

To sum up, you may lose around 2 pounds of weight per month. Note, you may or may not lose any weight at all. We don’t recommend using fasting as a potent way to shed calories. 

See also
The Vegetarian Intermittent Fasting Guide to Plant-Based Fasting and Feasting

Instead, focus on a long-term nutritious diet, loaded with fiber, protein, and a variety of nutritious foods from all food groups. 

Fiber is particularly crucial for your weight loss goals since it contributes to strong microbiome health, helps us avoid blood sugar spikes, and makes us feel full on fewer calories (13).

Here is the simple strategy for losing weight healthily: nutritious meals +exercising+hydration+enough sleep+positive mood. Instead of anticipating quick results, focus on the quality of your meals and your overall lifestyle. 

BetterMe app will provide you with a host of fat-frying fitness routines that’ll scare the extra pounds away and turn your body into a masterpiece! Get your life moving in the right direction with BetterMe!

What are the rules for a 2-day fast?

So, you have decided to try a 48-hour fast. Surely, doing it safely will help you reap the potential benefits and reduce the possibility of the aforementioned risks. Follow these 5 steps: 

  1. Stay hydrated: Drink enough fluids to maintain hydration. Opt for calorie-free beverages, like tea, water, and black coffee. 
  2. Drink electrolytes: Use electrolyte tabs or salts to enrich your water with minerals.
  3. Expect irritating hunger: You will naturally feel hunger pangs and cravings while fasting, sometimes in the middle of the night. Work on the willpower to avoid eating and complete the fast.
  4. Listen to your body: Stop the fast if you’re feeling strong exhaustion, fatigue, or dizziness. Your body may be telling you, this fasting is too much. 
  5. Reintroduce food slowly: After the fast enjoy a small, simple snack before the first proper meal. Examples include a broth, a piece of baked chicken, and a boiled potato. Overstimulating your digestive system may cause additional side effects, like: 
  • vomiting
  • diarrhea
  • bloating
  • nausea
  • flatulence (14).
See also
When Does Intermittent Fasting Start Working?

And remember, never extend the non-eating period. Some people experiment with fasting, not eating for longer, and transform it into starving without even realizing it. Fasting vs Starving is a huge difference. 

Read more: An 18-Hour Fast May Be Just Be What Your Body Needs for Optimal Health

2 day fast benefits  


  • How much weight will I lose in a 48-hour fast?

The 2-day fast once or twice per month may help you reduce your calorie intake by 8.000 calories per month. Converting that number of calories to pounds of fat is around 2 lb, however weight loss in real life is not so straightforward. You may or may not lose any weight at all by fasting for 48 hours, and if you do, it is more likely to be water weight which will return when you start eating again. 

  • How much weight can you lose in 72 hours fast?

You may or may not lose any weight at all by fasting for 72 hours, and if you do, it is more likely to be water weight which will return when you start eating again.

  • How much weight can you lose in 48 days?

In 48 days you may lose up to 14 pounds. To do so, maintain a 500- to 1,000-calorie-per-day deficit to lose 1 to 2 pounds per week. You may also lose a few extra pounds in the first couple of weeks as your body adjusts. Create the calorie deficit by making wise food choices and staying physically active.

  • Can I lose 10 kg in 50 days?

This is possible, but not for everyone. Dropping 10 kilograms in 50 days relies on various factors: your meal choices, metabolism, your body size, and your lifestyle. Your keys to achieving this goal involve consistency in your training, eating healthy fiber-rich food, drinking enough water, increasing your protein intake, reducing stress, and getting enough sleep. On top of that, track your progress and limit ultra processed foods as well as added sugars. A more sustainable goal for most people is to lose 0.5-1 kg per week. 

The Bottom Line

You have just gone over the main benefits and risks of a 2-day-fast. Now, let’s sum it up. 

A 48-hour fast means abstaining from food for 48 hours. It claims an array of possible benefits, such as enhanced brain functioning, reduced blood pressure and heart rate, and reduced markers of oxidative stress. 

Fasting may be linked to lowered inflammation by reducing oxidative stress in the body’s cells. It may improve insulin sensitivity, which helps your body transport blood sugar more efficiently. However, the evidence for these benefits is not conclusive. 

A 72-hour fast is a longer fasting period where you don’t eat for three days straight. During a 48- or 72-hour fast, the body enters a state of ketosis, where it starts to burn stored fat for energy instead of glucose from food. This might contribute to increased fat burning, enhanced insulin sensitivity, and potential benefits for type 2 diabetes and metabolic syndrome. However, there are also risks which should be discussed with your healthcare provider, especially if you have any health conditions or are taking any medications.  

Among the possible side effects of 48-hour fasting are hunger and hunger pangs, problems with digestion, dizziness, irritability, fatigue, nausea, insomnia, headaches, and fainting. 

It should go without saying, before entering fasting regimes, talk to your doctor.

The effective steps in following a 48-hour fast safely involve staying hydrated, drinking electrolytes, expecting hunger, listening to your body, and reintroducing meals gradually. 

Take care of yourself. 


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. Effect of 48 h Fasting on Autonomic Function, Brain Activity, Cognition, and Mood in Amateur Weight Lifters (2016,
  2. Effects of intermittent fasting on health markers in those with type 2 diabetes: A pilot study (2017,
  3. Enhanced thermogenic response to epinephrine after 48-h starvation in humans (1990,
  4. Fasting: Molecular Mechanisms and Clinical Applications (2014,
  5. Flipping the Metabolic Switch: Understanding and Applying Health Benefits of Fasting (2017,
  6. Inflammation-Induced Alteration of Astrocyte Mitochondrial Dynamics Requires Autophagy for Mitochondrial Network Maintenance (2013,
  7. Intermittent Fasting: The Choice for a Healthier Lifestyle (2018,
  8. Is fasting safe? A chart review of adverse events during medically supervised, water-only fasting (2018,
  9. Ketones and Human Performance (2017,
  10. Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine (2000,
  11. The effect of fasting or calorie restriction on autophagy induction: A review of the literature (2018,
  12. The inflammation theory of disease (2012,
  13. What Can Hunter-Gatherers Teach Us about Staying Healthy? (2020,
  14. What to know about 48-hour fasting (2023,
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