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How to Fast Properly to Reap Wellness Rewards

How to fast properly is the right question you should ask from the start. How can you fast to ensure you achieve the ultimate benefits? How can you ensure safety while fasting? Can you master intermittent fasting to achieve improved health and fitness? Yes, you can!

Knowing how to fast properly will make you more likely to see some benefits while reducing the risks of potential setbacks with intermittent fasting (IF). Let’s help you become an expert on fasting. 

How Long Should You Fast For?

How long you fast depends on the fasting type and program that works best for you; some popular choices include: 

  • 12-hour method (3)
  • 14/10 method (19)
  • 16/8 method (7)
  • The Warrior Diet (20)
  • Alternate-day fasting (8)
  • The 5:2 Diet (12)
  • 3-Day Fast (22)

Various fasting plans are available, as you can see. Let’s discover more about each one and others, before you determine which you should use. The coming guide will also help you determine which one suits you, depending on your individual needs. It is important to talk to your doctor before starting any fasting regimen. Certain medical conditions and medications must be taken into consideration, and note that some people should not fast.

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Time-Restricted Eating (TRE)

The 12/12 vs. 16/8 intermittent fasting schedules go head to head as two of the most popular TRE programs (3, 7). However, TRE is a form of intermittent fasting that limits your eating and fasting to specific times each day with multiple schedules, including: 

  • 12/12 Plan: The first plan encourages you to eat your regular calories for 12 hours daily while cutting drinks and food for the other 12 hours. It’s simple because you mostly sleep through your fast while you may lose weight if you reduce your overall calorie intake (3). 
  • 14/10 Plan: With the next TRE method, you’ll fast for 14 hours and eat during a 10-hour window. This method has been found to reduce weight, blood pressure, and blood lipids in patients with metabolic syndrome (19). It’s good to start with a shorter fasting window and work your way up as a beginner. 
  • 16/8 Plan: The 16/8 intermittent fasting plan suggests fasting overnight for 16 hours and eating all your regular calories within an 8-hour eating window. It may reduce inflammation, improve heart health risk factors, and help you lose weight (7). 
  • 20/4 Plan: The Warrior Diet is an intense fasting routine with a 4-hour eating window to consume calories. Medical News Today warns that it may be too strict for some and cause nutritional deficiencies, fatigue, or fainting (20). 
See also
What Can You Drink During Intermittent Fasting?

how to fast properly  

Alternate-Day Fasting

Alternate-day fasting (ADF) has two methods. The traditional method is eating your typical calories one day and zero calories the next. The modified version has you eating up to 30% of your calories on fasting days. It’s useful for beginners. Chinese researchers found that ADF helps people lose weight and may reduce the risk of chronic diseases (8). 

5:2 Method

Another popular fasting plan is the 5:2 method. You eat a normal amount, five days a week (but preferably healthy and balanced meals) and cut your calories to 500-600 for two non-consecutive days. The British Heart Foundation discusses the 5:2 Diet, indicating that there is some evidence to suggest it can help with weight loss and may improve risk factors for cardiovascular disease and diabetes (12). 

The Water Fast

The 3-day fast is a method to stay without food or drinks other than water for 24-72 hours (22). It requires proper guidance to ensure you remain hydrated. This is not for beginners and should be done under medical supervision.  

See also
The Stages Of Intermittent Fasting, Explained

Fasting Guidelines to Master Any Fasting Schedule

Knowing how to fast properly means understanding the basics and discovering necessary secrets to make everything work in your favor and prevent potential risks. Let’s help you find out how long you should fast and how to master every part of your journey. 

Who Shouldn’t Fast?

The first rule of fasting is to consult your doctor. The Cleveland Clinic suggests some people can’t fast safely, including (2):

  • Pregnant/breastfeeding moms
  • Women looking to conceive
  • Diabetics struggling to manage their glucose/insulin levels
  • Anyone with chronic kidney disease
  • Underweight people
  • Someone with a current or past eating disorder

The Cleveland Clinic recommends discussing fasting methods with your doctor if using chronic medication (2). You can also discuss supplements and multivitamins with a dietitian or doctor who knows how to plan fasting around your needs. 

How Should a Beginner Start Fasting?

For beginners, knowing how to fast will safely introduce your body to a fasting journey with a reduced risk of experiencing side effects. Dr. Nizar Zein suggests easing into a fast (2). Start by reducing your portions and calorie drinks for a few days before fasting.

Start filling up on protein and complex carbs while avoiding simple carbs as you near the fasting day. Also, plan ahead for any medication you may use during the fast. Furthermore, reduce high-intensity to low-intensity workouts and drink plenty of water, leading to the day. 

Stay hydrated during and after your fast with zero-calorie water. Finally, you’ll ease out of the fast with small meals. Avoid binging right after breaking a fast. Instead, spread your calories over 2-3 meals. Ease in and out of fasting to prevent fatigue, weakness, and hunger (2). 

Another way to ease into fasting is to begin with the 12/12 and slowly progress to longer fasting periods. 

how to fast properly  

How Many Hours Is a Good Fast?

The 16/8 fasting plan is a popular schedule, but starting slow and progressing to longer fasts may work. Harvard states that 12 hours of fasting may be long enough to trigger ketosis (21).

See also
Keto Vs Intermittent Fasting: Is One Better Than The Other?

How to Fast for a Day

Eat dinner before 8 p.m. and don’t eat until 8 a.m. the next morning using the 12/12 method (3). Alternatively, eat your last meal before 8 p.m. and only eat again at 10 a.m. the next day using the 14/10 method (19). Finally, eat dinner before 8 p.m. and only eat the next day at noon if using the 16/8 method (7).

Read more: Intermittent Fasting Schedule for Women: Benefits and Best Practices

How to Do a 3-Day Fast Correctly

Knowing how to fast safely for 3 days will save you a lot of trouble and potential risks. Medical News Today discusses that typical water fasting means that you remain without food or drinks other than water for 24-72 hours (22). Always discuss a 3-day fast with your doctor before entering one. 

However, don’t fast if you feel unwell. Otherwise, you may eat a nutritionally dense meal before 8 p.m. the night before starting the water fast. Stop strenuous activities before you start, and choose 3 days when you can rest. Finally, remaining hydrated is essential.

Mineral water provides fluid and some of the electrolytes you need during the fast, but you can also use supplements or a multivitamin suggested by a dietitian or doctor. 

How to Fast to Lose Weight

Our fasting diet plan will help you consume nutrients while losing weight with fasting (1). Also, intermittent fasting exercise can help you shed pounds without putting too much stress on your body during the fast (10). Fasting, the right exercise, and proper nutrition shed pounds.

10 Top Tips to Master Fasting

Fasting on any schedule requires following guidelines to avoid potential side effects. Follow these tips to fast like a pro and achieve any wellness goal: 

  • Stop fasting if you feel unwell. Austin researchers suggest you stop fasting if you experience excessive fatigue, insomnia, nausea, headaches, digestive issues, or unexplained pain (11). 
  • Eat small amounts of food on fasting days if you struggle with strict schedules. For example, modify the 5:2 method to eat up to 25% of your calories on fasting days (12). 
  • Drink enough fluids during and between fasts. French research shows that around 20-30% of your fluids come from food (6). Replace that fluid loss with the recommended 2-3 liters of water daily (13).
  • Break a fast with a smaller calorie intake. Eating too much when you break a fast can sometimes lead to bloating and gas (15). 
  • Washington scientists found that eating too little protein during weight loss may cause muscle loss (17). Eat more protein and engage in workouts to strengthen muscles.
  • The UC Davis Department of Nutrition warns that some people may lack nutrients when they fast (16). Take a multivitamin, or speak to a dietitian about supplements. 
See also
Intermittent Fasting for Women Over 40. Is it Healthy? 

how to fast properly  

  • Eat healthy balanced meals to keep your nutritional balance between fasts. Medicine Net suggests adding lean protein from legumes, pulses, chicken, fish, and turkey (23). Also, eat plenty of high-fiber vegetables, whole grains, and healthy fats. 
  • Missouri researchers suggest that intermittent fasting and the Mediterranean diet can be done together (5). Try eating a Mediterranean-style diet between fasts. 
  • Medicine Net also suggests you avoid simple carbs and high-calorie foods between fasts (23). Also, limit any calorie drinks, such as coffee with milk or soda.
  • Finally, stick to the FDA’s recommended limit of 400 milligrams of caffeine daily if you drink black coffee during fasting (18). Soda, tea, and chocolate also have caffeine. 

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See also
Intermittent Fasting Snacks: 10 Plus Healthy Bitings That Will Help You Stay On Track

For more ways to master fasting: 


Is Fasting for 3 Days Healthy?

We can’t say if it is healthy or safe for you. That is a discussion for you and your healthcare provider. Medical News Today suggests a typical water fast lasts anywhere from 24 hours to 3 days (22). However, don’t exceed 24-72 hours without consulting your doctor. A medically supervised water fast might go longer than three days. Even for shorter fasts, it’s a good idea to talk to your healthcare provider first.

What Happens if You Don’t Eat for 5 Days?

Not eating for five days will lead to metabolic adaptations to starvation. You should not fast that long without being medically supervised, so discuss it with your healthcare provider first.  

What’s the Longest You Can Fast Safely?

Water fasting is thought to be safe for up to three days before seeking medical supervision (22). However, you can go longer with supervision if desired and determined to be safe by you and your healthcare provider (14). The National Library of Medicine shares Alan Goldhamer’s medically supervised water fast that lasts 5-40 days (4). 

This period is only safe under strict medical supervision if you aren’t eating any nutrients. Also, Polish researchers completed a small study where 12 middle-aged men safely water fasted for 8 days under supervision (13). Please, only do longer fasts under supervision!

Does Sleep Count as Fasting?

Sleep is a natural fasting state, whether you’re on a program or not. It’s easier to sleep through your fasting periods and keep eating windows during the day. 

The Bottom Line

Knowing how to fast properly might help you lose weight or meet your health goals with less risk. Start slow and progress as your body adapts to the fasting schedules. Also, embrace the best fasting tips to ensure you master the art of intermittent fasting. 


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. 5-Day Fasting Diet Meal Plan – Detailing What to Eat During Intermittent Fasting (2023,
  2. 5 Tips for Healthy Fasting (2022,
  3. 12-Hour Intermittent Fasting For Weight Loss And Other Benefits (2023,
  4. Alan Goldhamer, DC: Water Fasting—The Clinical Effectiveness of Rebooting Your Body (2014,
  5. A Pesco-Mediterranean Diet With Intermittent Fasting: JACC Review Topic of the Week (2020,
  6. Contribution of Water from Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys (2016,
  7. Effects of Eight Weeks of Time-Restricted Feeding (16/8) on Basal Metabolism, Maximal Strength, Body Composition, Inflammation, and Cardiovascular Risk Factors in Resistance-Trained Males (2016,
  8. Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis (2020,
  9. Intermittent Fasting and Sleep: A Review of Human Trials (2021,
  10. Intermittent Fasting Exercise For Safe Weight Loss And Muscle Preservation (2023,
  11. Is Fasting Safe? A Chart Review of Adverse Events During Medically Supervised, Water-Only Fasting (2018,
  12. Is the 5:2 Diet a Good Way to Lose Weight – Ask the Experts (n.d., 
  13. Is Water-Only Fasting Safe? (2021, 
  14. Ketosis: Definition, Benefits, & Side Effects (2022,
  15. Meteorism – StatsPearls – NCBI Bookshelf (2022,
  16. Nutrition & Health Info Sheets for Health Professionals (n.d.,
  17. Preserving Healthy Muscle During Weight Loss (2017,
  18. Spilling the Beans: How Much Caffeine is Too Much? (2023,
  19. Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients With Metabolic Syndrome (2021,
  20. The Warrior Diet: Pros, Cons, How to Follow It, and Examples (2020,
  21. Time to Try Intermittent Fasting? – Harvard Health (2023,
  22. Water Fasting: Benefits, Weight Loss, and How to Do It (2023,
  23. What Do You Eat on Intermittent Fasting? (2022,

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