Here Are The Health Benefits Of A 48 Hour Fast

Intermittent fasting is a popular approach to dieting and weight management, but some people find that having to restrict the window of time that you eat every day starts to become tedious and difficult to sustain. 

For this reason, some people find that there are logistical benefits of a 48 hour fast rather than a routinized intermittent fasting diet.

But, what are the benefits of a 48 hour fast once a week or once a month? Are there good 48 hour fast weight loss results? And do 48 hour fasting benefits outweigh the discomfort of fasting for 48 hours?

In this article, we will discuss the benefits of a 48 hour fast, how to do a 48 hour fast, and expected weight loss results to help you decide if this approach to fasting and weight loss is right for you.

We will cover the following: 

  • What Is a 48 Hour Water Fast?
  • How to Do a 48 Hour Fast
  • Potential Health Benefits of a 48 Hour Fast

Let’s dive in! 

A person drinking a glass of water.

What Is a 48 Hour Water Fast?

A 48 hour water fast, called 48 hour water fasting, involves abstaining from consuming any food and any beverage that contains calories for two full days.

There are various reasons why people take on intermittent fasting or more prolonged fasts such as a 48 hour fast.

However, most people who are not fasting specifically for spiritual reasons are most interested in 48 hour fasting weight loss results and some of the other health benefits such as improved blood sugar regulation, decreased inflammation, and a dietary reset if you’ve been experiencing a sugar addiction or other food cravings.

How to Do a 48 Hour Fast

Before we look more specifically at some of the other 48 hour fast benefits, let’s briefly look at how to do a 48 hour fast.

It may sound very simple to do a 48 hour fast; however, it is not easy.

A person drinking a glass of water.

A 48 hour fasting protocol involves abstaining from all food and caloric beverages for 48 hours. You can only drink water, seltzer or club soda, herbal tea, caffeinated tea, or black coffee, all of which must be unsweetened and free from any milk, creamers, etc. 

It is encouraged to have electrolyte tablets or add unsweetened electrolyte powders to your calorie-free beverages that you drink while fasting in order to help maintain proper electrolyte balance.

It is also critical to note that before you try fasting for 48 hours, you should speak with your healthcare provider and obtain medical clearance and guidance to ensure that it is safe for you and will be effective for whatever benefits of fasting 48 hours that you are seeking.

In many cases, if you are primarily looking to obtain significant 48 hour fast weight loss results, there are equally effective (if not more effective) and safer routes to sustainable weight loss and body composition changes.

Intermittent fasting diets with less extreme fasting windows as well as following a nutritious, calorie-controlled diet combined with regular physical activity, can often provide many of the weight loss benefits of fasting 48 hours without the metabolic stress and potential risks of prolonged fasting.

A person drinking a glass of water.

Long-term fasting can result in dangerous electrolyte and blood sugar imbalances or deficiencies that can potentially affect your cognition, decision-making ability, focus, nerve conduction, fluid balance, muscle contraction, and even heart rate and rhythm.

A 48 hour fast may also result in adverse health and metabolic changes such as dehydration, a loss of lean muscle mass, hyperuricemia, hyponatremia, protein sparing, sodium and potassium-sparing, decreased serum calcium and magnesium levels, and acidic urine.

To this end, while there are indeed some impressive 48-hour fasting health benefits, and studies suggest that prolonged fasting can be safe, prolonged fasting protocols such as fasting 48 hours are contraindicated for many individuals. 

Examples of people who should not fast for 48 hours or who absolutely need to obtain medical clearance before doing so include:

  • Women who are pregnant or breast-feeding
  • People who have an active eating disorder or a history of an eating disorder
  • People with a BMI that falls within the “underweight“ category
  • People who take certain medications
  • People with type one diabetes or other blood sugar regulation issues
  • Those with other chronic conditions, such as kidney disease
A notebook page that says benefits.

Potential Health Benefits of a 48 Hour Fast

48 hour water fasting is extremely physically, mentally, and emotionally taxing.

Therefore, it is helpful to understand the potential health benefits of a 48 hour fast to help motivate you through the tough portions of the fast if you and your healthcare team decide that this approach to weight loss and health is a good idea for you.

So, what are the main 48 hour fasting benefits? What are the potential 48 hour fast weight loss results?

In general, there are numerous potential benefits of occasionally doing prolonged fasts or engaging in intermittent fasting with more regularity

A review of 27 intermittent fasting dietary interventions found that all 27 studies resulted in weight loss of 0.8% to 13.0% of the starting weight with no serious adverse events.

Therefore, most people do find that they lose weight fasting 48 hours and experience a reduction in body fat percentage.

A clock and utensils on an empty plate.

This is because fasting 48 hours creates a significant caloric deficit, which is necessary to lose body fat.

Moreover, some of the reported benefits of fasting 48 hours aside from weight loss include the following:

Once you’ve gotten through your first 48 hour fasting protocol, you might wonder if there are benefits of fasting 48 hours once a week.

A clock and utensils on an empty plate.

Ultimately, whether you are doing a 2-day fast once a week, once a month, or once a year, many of the aforementioned benefits of fasting for 48 hours will be visualized with whatever frequency you engage in this practice with the caveat that some of the 48 hour fast benefits might follow the law of diminishing returns.

This is to say that if you are doing a 48 hour fast once a week, some of the benefits of a 48 hour fast may not become quite as significant with such frequent fasting. 

The human body is highly adaptable and adjusts to whatever type of routine we put it through, be it a consistent exercise routine of the same workout day after day, the same diet without adjusting your meals or caloric intake, or the same sleep schedule.

The ability of the body to adapt to positive and negative stresses and our routines is beneficial in many ways and has important survival implications, but it does mean that the body will become more efficient and less responsive to the significant caloric deficit induced by fasting 48 hours.

Practically, what you may notice is that the weight loss benefits of fasting 48 hours once a week become less significant than if you fast 48 hours once a month.

A plate made into a clock representing intermittent fasting.

In order to help prevent the body from becoming well-adapted to a weekly 48 hour fast for weight loss and health, it is generally best to keep your routine as varied as possible. 

This may look like fasting 48 hours and one week, and then engaging in an intermittent fasting diet like the 16/8 intermittent fasting diet or the 20/4 intermittent fasting diet for the following week. 

Then, on the third week, you can do another 48 hour fast, or perhaps a 24 or 36 hour fast, and then some other type of intermittent fasting diet schedule the following week. 

Incorporating different types of fasting and different durations of short-term intermittent fasting and longer water fasting protocols may help you get all of the benefits of fasting while keeping your body “guessing“ and unable to fully adapt and become so efficient with your 48 hour fasting protocols that you stop gleaning the full benefits.

Not sure if a 48 hour fast is right for you? Check out our guide to a 24 hour fast once a week to see if that might be a better fit for your needs.

A person smiling.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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