50-Hour Fast: What to Know Before Trying It

Curious about the 50-hour fast and what might happen to your body during that time? You’re not alone! Intermittent fasting has become a popular topic, and longer fasts like the 50-hour mark are often discussed with a mix of interest and caution. 

In this article, we explore what research considers about a 50-hour fast and the practical points to weigh before trying one.

Every fast is a personal experience. Your dietary preferences, body composition, and activity level can influence how fasting feels. Consult a healthcare professional before embarking on a fasting regimen.

What Should You Consider Before a 50-Hour Fast?

A 50-hour fast is a prolonged fasting approach and may not suit everyone. Individual responses can vary, particularly when someone has little fasting experience. 

However, it’s crucial to consider individual circumstances, as fasting effects vary from person to person. 

Think of it like this: just as a specific workout routine works differently for different people, so too will fasting (1).

Here’s what to consider:

• Individual health status: Consider your overall circumstances before starting a prolonged fast. If you have an ongoing health concern or take medication, consult a healthcare professional before attempting a 50-hour fast.
• Your goals behind the fast: Consider why you are interested in fasting, but avoid treating one fasting window as a guaranteed route to a particular outcome.
• Lifestyle and activity level: Your routine can influence energy needs during a fast and when you resume eating. Consider keeping activity manageable during the fasting period.
• Previous fasting experience: If you are considering fasting, shorter windows may be easier to evaluate before attempting a longer one. Seek professional guidance if you are unsure.
• The Frequency of Fasting: Are you planning to make 50-hour fasts a regular part of your routine, or is this a one-time experiment? 

Frequent long fasts may not suit everyone, so pay attention to how you feel and seek professional guidance if you are unsure.

What is the expected outcome of a 50-hour fast?

The expected outcome of a 50-hour fast is highly individualized. 

Consider your goals, eating patterns, and daily routine before choosing a fasting approach. 

Consult a healthcare professional before embarking on an extended fasting regimen.

If you are comparing longer fasting windows, see our 48-hour fast guide.

What Happens To Your Body During A 50-Hour Fast? 

During a 50-hour fast, the body changes how it uses available energy as food intake pauses.

The following phases offer a general overview. Individual experiences and study findings can vary:

• 0-12 Hours: In this phase, your body continues to use glucose from the last meal. As these reserves decrease, the body begins to mobilize stored glycogen from the liver. Insulin levels start to drop as your body prepares for a period without food. It’s normal to feel slight hunger pangs, but generally, you feel fine (3).
• 12-24 Hours: As time passes, glycogen reserves in your liver begin to diminish. Once glycogen is exhausted, the body starts to seek alternative energy sources. Your body begins to produce ketone bodies from fat, which eventually become the new primary energy source. Some people might feel a bit tired or confused as the brain adapts to this new fuel (4).
• 24-36 Hours: Researchers continue to study how fasting influences cellular processes. The timing and relevance of these processes can vary and should not be used to predict individual outcomes.
• 36-50 Hours: As a fast continues, energy needs and how people feel may change. There is no single fasting duration that suits everyone. 

The timing of cellular processes during fasting remains an active area of research and varies across studies and individuals.

For a broader timeline, explore fasting benefits by hour.

What Does Research Explore About Longer Fasts?

Research on fasting examines several body processes, but findings vary by study design, fasting pattern, and participant. A single 50-hour fast should not be treated as a guaranteed route to a particular outcome.

Here are several areas researchers continue to examine:

• Cardiovascular and Insulin Sensitivity Benefits:

Some studies explore how fasting patterns relate to metabolic markers, but the findings do not establish that a 50-hour fast will produce a specific outcome for an individual.

• Promotion of Weight Loss:

Fasting may change when and how much someone eats, but changes in body weight vary widely and depend on overall habits and individual circumstances.

• Cellular processes:

Research also explores cellular processes during fasting, although the timing and implications for people remain uncertain. 

No single fasting duration has been established as appropriate for everyone.

• Reduction in Inflammation:

Researchers are also studying fasting and inflammation; available findings should not be read as a promise to prevent or manage a condition.

• Positive Impact on Gut Microbiota:

Research continues on fasting, digestion, and the microbiome, but its practical implications for an individual remain uncertain.

• Potential Longevity Benefits: 

The potential advantages of fasting could extend to increased longevity. However, most research in this area has been done in animals, so the relevance for humans is still largely unknown (7).

Most of these 50-hour fast benefits are potentially associated with consistent intermittent fasting, not a single prolonged fast, and no particular length of fast. 

If 50 hours seems too long for you, then start with something more achievable. 

Fasting may affect meal timing and overall intake, but it does not guarantee a particular change in body weight or health. 

No fasting schedule is a universal fit, and a general article cannot determine what is appropriate for an individual. 

Read more: 36- vs 48-Hour Fast: Which One Should You Do?

Who Should Seek Professional Advice Before a 50-Hour Fast?

Extended fasting may not be suitable for everyone. If you take medication, have an ongoing health concern, are pregnant or breastfeeding, have a history of disordered eating, or are unsure whether fasting is appropriate, consult a healthcare professional before considering it. 

Each person has different needs and eating patterns that can influence how fasting feels and whether it is appropriate.

Below, we explore some groups of people who, in general, should avoid fasting:

• People with a history of disordered eating: Fasting may be difficult or inappropriate; seek professional guidance.
• Pregnant or breastfeeding people: Nutritional needs can differ; seek professional guidance before making dietary changes.
• People taking medication or managing ongoing health concerns: Seek professional guidance before fasting.
• People who notice fasting affects their mood or daily functioning: Stop and speak with a qualified professional.

A balanced approach to nutrition and physical activity, guided by professionals when appropriate, can support sustainable well-being over time.

What Are The Biggest Mistakes In 50-Hour Fasting?

It’s easy to fall into inevitable common mistakes that could diminish benefits or even be counterproductive!

Here are common considerations for someone thinking about a prolonged fast:

• Not preparing adequately: Consider your routine and hydration before fasting, rather than expecting a longer fast to deliver a particular result.
• Ignoring Body Signals: Listening to your body is crucial. Never ignore signs of dizziness, weakness, or extreme fatigue. If something feels off, consider breaking the fast (12).
• Wrongly Resuming Eating: After 50 hours without food, your digestive system may be a little sensitive. Many people mistakenly consume heavy foods immediately, which can lead to discomfort and counteract the benefits of fasting. Don’t worry, keep reading for tips on reintroducing food!
• Not Staying Hydrated: During a fast, the focus often shifts to food, neglecting hydration. Dehydration could lead to fatigue and affect your well-being.
• Setting unrealistic expectations: It is tempting to expect rapid results from an extended fast, but changes in body weight are gradual and vary from person to person. Wondering, “How long should you fast for weight loss?” will not help you reach your goals, as it’s essential to focus on how to keep the weight off sustainably.
• Seeking professional advice: If you are new to fasting, take medication, or have an ongoing health concern, speak with a qualified healthcare professional before starting a prolonged fast.

Workouts, weight management tools, and recipe ideas come together in the BetterMe: Health Coaching app, giving you practical support for building a more consistent wellness routine.

How Can You Prepare for a 50-Hour Fast?

Here are some general considerations before a 50-hour fast:

• Establish a Fasting Plan: Before starting, it’s helpful to have a clear plan. Decide the exact time you’ll begin the fast and when you will break it. 

Consult a healthcare professional for individual guidance. This can help you decide whether fasting is appropriate for your circumstances.

• Gradually Increase Your Intake of Healthy Foods: In the days leading up to the fast, ensure you increase your consumption of healthy and nutritious foods. Include plenty of fruits, vegetables, lean proteins, and healthy fats in your diet. 

This balanced diet will help your body build reserves of energy and nutrients. Additionally, reduce foods high in sugars and highly processed items.

1. Stay Hydrated: Hydration is key before and during the fast. Be sure to drink enough water in the days leading up to it, and avoid dehydrating beverages like alcohol and excessive coffee.
2. Listen to Your Body: Pay attention to how your body feels in the days leading up to the fast. If you experience extreme fatigue, dizziness, or discomfort, it might be a sign that you need to adjust your preparation. 

Before deciding on your first meal, review how to break a fast.

Also, make sure to get enough rest and try to manage stress effectively.

How Can You Break a 50-Hour Fast Gradually?

After a 50-hour fast, some people may prefer to reintroduce food gradually. Consider how you feel and seek professional guidance if you have concerns.

A gradual and mindful reintroduction of foods may feel more comfortable for some people.

Steps to Break the Fast:

• Start with Small Portions and Liquids

Begin with a glass of water or broth. Avoid sugary or caffeinated beverages. 

After that, opt for a small portion of easily digestible food, such as steamed or boiled vegetables, scrambled eggs, steamed or grilled white fish, or unsweetened natural yogurt.

• Avoid Heavy, Fatty, or Sugary Foods

Avoid ultra-processed, packaged foods that are high in sugar, salt, and unhealthy fats.

• Gradually Reintroduce Solid Foods

As the hours go by and you feel comfortable, you could gradually increase the size of your portions and start eating other foods. You might begin to introduce more complex foods such as legumes (soaked and properly cooked), whole grains (like quinoa or brown rice), and lean meats.

• Stay Hydrated!

Drink plenty of water and consider including electrolyte-containing drinks to replenish what was lost during the fast (consult with a health professional!).

• Listen to Your Body’s Signals

Make sure to pay attention to how your body feels. If you experience discomfort, reduce the amount of food or take a break before eating again.

Successfully breaking a 50-hour fast requires patience, planning, and attention. 

Remember that everyone is different, so it’s important to adapt these recommendations to your own needs and tolerance.

What Might You Drink During a 50-Hour Fast?

Before delving into specific beverages, it’s essential to understand why hydration is so vital during fasting. When you don’t eat, your body begins to use its glycogen reserves (stored glucose) for energy. This process, called glycogenolysis, releases water, which could lead to fluid loss (13).

Allowed Beverages During Fasting

• Water: A common option. You can consume mineral water, plain bottled water, or filtered water.
• Tea: Unsweetened teas, such as green, black, or herbal teas (like mint or chamomile), are excellent. Be sure not to add sweeteners, and try not to go overboard with caffeine intake.
• Black Coffee: Without sugar, milk, or cream. Black coffee could help suppress appetite and has antioxidant benefits. Again, try to keep your total caffeine intake reasonable.
• Bone Broth (optional): While it contains some calories, some people use it to obtain electrolytes. However, this depends on the type of fast you are undertaking and how flexible you prefer to be.
• Calorie-Free Electrolyte Drinks: Look for options that contain no sugars or calories. You can make a mixture of water with a pinch of sea salt and a little lemon juice.

Read more: Foods to Avoid When Breaking a Fast + Practical Tips

How Often Might Someone Consider a 50-Hour Fast?

There is no universal frequency for a 50-hour fast. A healthcare professional can help you decide whether fasting is appropriate for your circumstances.

However, some general guidelines can serve as a starting point. 

If you’re new to prolonged fasting, seek professional guidance before considering a longer fasting window. 

• For beginners, start with shorter fasts, such as 12 hours. 
• If you’re experienced, consider a 50-hour fast once a month, watching your body’s reactions. Although some may manage a 50-hour fast every 2-3 weeks, monitoring your health is essential. Some might benefit from more frequent fasting (for example, to manage blood glucose levels under medical supervision), while others should fast less or not at all.

Regardless of the frequency chosen, pay attention to the signals your body sends, such as energy levels, sleep quality, mood, and digestive health. 

If you experience adverse effects, reduce your fasting frequency or consult a healthcare professional. Lastly, as mentioned, frequency is not the only factor to consider. Always remember to take into account preparation, post-fast meals, and activity levels in your fasting journey. 

Avoid using a fixed schedule from a general article as individual guidance. If you choose to fast, consider your daily routine and speak with a healthcare professional first. 

BetterMe: Health Coaching app can help you build a more structured approach to your wellness routine with meal plans, workouts, and habit-tracking tools. Start using the app to explore options that may support your personal fitness and nutrition goals.

FAQs

• Can you exercise during a 50-hour fast?

You could exercise during a 50-hour fast. Many people find that they can still maintain their workout routines, even with light to moderate exercise. However, it’s essential to listen to your body; some might feel fatigued or weak.

• Does coffee break a fast?

No, black coffee typically does not break fast. It’s low in calories and can even help suppress appetite. Just remember to skip the cream and sugar!

• Does vitamin D break a fast?

Vitamin D generally does not break a fast if taken in its natural form. However, if it’s in an oil or contains added sugars (like a gummy), it could have a slight calorie impact. 

• Can I eat boiled eggs during fasting?

Eating boiled eggs during a fast would break it, as they contain nutrients and, therefore, caloric content. However, they are a nutritious option for when you decide to eat again after fasting.

The Bottom Line

If you are considering undertaking a 50-hour fast, it is essential to prepare adequately and understand what this practice entails.

Before starting, consult with a registered dietitian or healthcare provider for individual guidance, especially if you have any health concerns.

Preparation is key. Choose a time that is moderately peaceful to focus, where you can avoid stressful periods, and stay well-hydrated to help manage hunger and maintain energy. 

When you reach the end of the fast, make sure to break it with soft, easily digestible foods. This fasting tip will help your digestive system readjust to the intake of solid foods.

Ultimately, a 50-hour fast could be a transformative experience, but it is crucial to approach it with the correct information and professional support.