The Ultimate Intermittent Fasting Guide: The Only Guide You Will Ever Need

Do you want a complete intermittent fasting guide? If so, you have come to the right place. Here you will learn everything you need to know about intermittent fasting!

intermittent fasting guide

If you have been looking for the ultimate intermittent fasting guide, look no further! Intermittent fasting has been around for a long time – and for good reason!

Read on to find more about:

  • The benefits of intermittent fasting
  • How to get started with intermittent fasting
  • The different types of intermittent fasting schedules
  • What to eat/drink while fasting

What Is Intermittent Fasting?

Intermittent Fasting (IF) is an eating pattern where you cycle between times of eating and not eating (fasting).

Humans have actually been fasting for years. “Up until about 12,000 years ago, humans got their food by hunting, gathering or fishing. As foragers, they would fast until they found, caught or killed their food. There was no breakfast upon waking, or leftovers for lunch. They ate opportunistically, according to Inverse.

Also at the time, humans did not consume nearly as much as we do now. When there was no electricity and no refrigerators, humans ate from sun up until sundown. Today, we eat all hours of the day. If it’s dark when we wake up, we can still have access to food. If we want a midnight snack, the refrigerator light is always working.

Benefits Of Intermittent Fasting

There are so many benefits of IF. Here are just a few of the many benefits.

It Makes Your Days And Life Simpler

Intermittent fasting takes stress out of your day and reduces decision fatigue. You no longer have to wonder what you should eat and rely on your willpower to eat healthy foods. Fasting tells you when to eat and in general makes your life a whole lot simpler.

Fasting also means less dishes to wash, less meals to cook and less groceries to buy!

Weight Loss

Our body shifts into fat-burning mode when they don’t get food for an extended period of time. Our body’s first source of fuel is glycogen, and it only turns to burning body fat once that quickly available energy source (glycogen) is depleted. When you fast for long enough, you drive down stores of glycogen and start burning fat tissue.

Insulin Resistance

According to Dr. Jason Fung, “insulin itself causes insulin resistance. As we (doctors) prescribe insulin to type 2 diabetes, patients don’t get better, they get worse. Their blood glucose is better, but they gain weight and they still develop all the complications – heart disease, stroke, kidney disease, blindness, etc.”

“The correct treatment is to empty out the BODY, not just the blood of the excessive glucose. How? Low carb diet and intermittent fasting. And guess what? That’s EXACTLY what we see clinically. As we (doctors) start fasting type 2 diabetes patients, they lose weight, their medication requirements go down and eventually it reverses.”

Reduced Inflammation

There are a number of factors in our day-to-day lives that can trigger inflammation throughout the body. High-stress levels, exposure to cigarette smoke, pollution, and poor sleep patterns can all result in inflammation, according to dietician Chole McLeod.

Fasting may assist in managing inflammation by:

  • Changing how compounds and proteins interact with each other, inhibiting inflammatory pathways.
  • Reducing inflammatory biomarkers, such as CRP, homocysteine and cholesterol ratios.

Heart Health

According to Mayo Clinic, regular fasting can decrease your low-density lipoprotein, or “bad,” cholesterol. It’s also thought that fasting may improve the way your body metabolizes sugar. This can reduce your risk of gaining weight and developing diabetes, which are both risk factors for heart health and heart disease.

Brain Health

Intermittent fasting may have important benefits for brain health. It may increase the growth of new neurons and protect the brain from damage.


When you fast, your cells are given time to detox and recycle, so your body can slow down the aging process and help prevent age-related diseases. (Physical IQ)

Cellular Repair

“Cycles of fasting can reset and rejuvenate the human body,” said Valter Longo, director of the Longevity Institute at the University of Southern California. “Periods with no food help the body eliminate and replace damaged cells with new ones through a process called autophagy.”

Increased Human Growth Hormone (HGH)

HGH is a hormone made by the pituitary gland (the master gland), which plays a huge role in the normal development of children and adolescents as the name implies. However, it also plays a role in adults. HGH deficiency in adults leads to higher levels of body fat, lower lean body mass and decreased bone mass. (Diet Doctor)

Fasting is a great stimulus to HGH secretion. Fasting has the potential to unleash the anti-aging properties of HGH without any of the problems of excessive HGH (prostate cancer, increased blood sugar, increased blood pressure). For those interested in athletic performance, the benefits are even greater. -Dr Jason Fung 

How Do You Start Intermittent Fasting?

You can start intermittent fasting very easily! Get started with the 16:8 schedule. This means that you fast for 16 hours per day and eat for 8 hours per day.

Here’s how to get started:

  1. Download an intermittent fasting app. My favorites are Zero and Window.
  2. When you finish eating dinner, start your fasting timer on your fasting app. If you finish eating by 8pm, you can eat at 12pm the next day! This means you are simply skipping breakfast!
  3. Be consistent. Be consistent with your 16:8 schedule for at least a month. By a month in, fasting should feel easier and you should be seeing results!

Intermittent Fasting Schedules

11 Types Of Intermittent Fasting

  • Circadian Rhythm Fast
  • 16:8
  • 18:6
  • 20:4
  • 36 hour fast
  • One Meal A Day (OMAD)
  • Alternate Day Fasting (ADF)
  • 5:2
  • 4:3
  • Fasting Mimicking Diet (FMD)
  • Eat Stop Eat

Circadian Rhythm Fast

The circadian rhythm fast is based on the research of Dr. Satchin Panda. This fasting method follows the body’s natural clock by fasting from after the sun sets until morning. Usually, this is about a 12-13 hour fast for most people.


The 16:8 method is 16 hours of fasting and an 8-hour eating window. Many people who follow 16:8, fast from after dinner until lunch the next day. But you can adjust the schedule to fit your lifestyle.


The 18:6 method is 18 hours of fasting and a 6-hour eating window. 18:6 helps the liver to get rid of more glycogen, allows the body to start using ketones for fuel and can start autophagy to clean out damaged cells and regenerate newer cells.


The 20:4 method is 20 hours of fasting and a 4-hour eating window. 20:4 helps your body work toward becoming fat adapted.

36 Hour Fast

The 36 hour fast is known as the Monk Fast. This fast promotes cellular cleansing benefits and can help to reset the metabolism.

48 Hour Fast

The 48 hour fast helps improve gut bacteria, improve dopamine receptor sites and open up dopamine pathways. This fast is often referred to as the dopamine reset fast. This fast is great for mental health.

72 Hour Fast

The 72 hour fast is a 3 day fast that resets your immune system, accelerates healing, and repairs neurons in the brain. This fast was made popular by Dr. Valter Longo.

One Meal A Day (OMAD)

One meal a day, often called OMAD, is fasting for 20+ hours and then eating one meal. While different people have different opinions about OMAD, OMAD does not mean only a 1-hour eating window or just one plate of food. If you are fasting for most of the day and have one meal, you are following OMAD. You get to make OMAD work for you! Some people choose to have a snack and a meal for OMAD, others include dessert too!

Alternate Day Fasting (ADF)

Alternate Day Fasting (ADF) is a method where you alternate between fasting days and eating days. When following ADF, eating days are often called up days and fasting days are often called down days. The ADF schedule is one up day, followed up one down day.

It is important to note that more fasting and longer fasting windows are not better. When you have a fasted day, it is recommended that you follow it by a full up day to properly follow ADF. After a down day of 36-42 hours of fasting, you need more than one meal, which is why a full up day is recommended.


5:2 is a method of alternate day fasting. The “5” and the “2” refer to days, not hours like time restricted eating. The 5:2 method means 5 days of the week you eat normally and 2 days of the week you fast. The two days of fasting should not be consecutive and should range from 36-42 hours of fasting.


4:3 is a method of alternate day fasting. In this method, you have 4 up days (full eating days) and 3 fasting days. A fasting day or down day is anywhere from 36-42 hours of fasting.

Fasting Mimicking Diet

The fasting mimicking diet was developed by Valter Longo. This method is meant to be followed 5 days per month. The rest of the month you eat normally. During those 5 days, calories are restricted for a set period of time to mimic a fast. Longo developed a program called ProLon Fasting Mimicking Diet which sends you a kit with everything to eat for the 5 days.

Eat Stop Eat

Eat Stop Eat is a method created by Brad Pilon. This method involves two 24-hour fasts per week, on non-consecutive days. The remaining 5 days of the week you eat normally.

For more information and the benefits of each fasting type, check out our guide on the different types of intermittent fasting.

How To Pick A Fasting Schedule

If you are just getting started with intermittent fasting, I would start with a 12 hour fast and work your way up. To determine which fast is best for you, you need to look at your health goals.

If you are fasting to lose weight, you can pick any fast that you can stick with. The fast that you can be consistent with is the best choice. Many people follow 16:8 and achieve weight loss. Typically, the shorter your eating window, the quicker you will see weight loss results.

If you are fasting for longevity, alternate day fasting (ADF) or quarterly extended fasts are best.

If you are fasting to maintain your weight, you just need to maintain a fasting regimen. Again, pick the best choice for you. If you are fasting clean and not spiking your insulin levels during your fast, you will be able to maintain your weight effortlessly.

What Can I Eat While Fasting?

Nothing! You should not be eating anything while you are fasting. If you consume anything, you will spike your insulin levels and you will no longer be in a fasted state.

What Can I Drink While Fasting?

While you are fasting, you can drink:

  • Water (unflavored, no added fruit)
  • Black coffee
  • Plain green tea or black tea
  • Mineral water, unflavored sparkling water or seltzer water
  • Salt, electrolytes or minerals (unflavored, no additives)

For more information, check out our guide on what can I drink while fasting.

What Is A Clean Fast?

A clean fast is not consuming anything that spikes your insulin levels while you are fasting. During a clean fast you can consume water, black coffee, plain green or black tea, mineral water, unflavored sparkling water, seltzer water, salt, unflavored electrolytes and unflavored minerals.

The term “clean fast” was originated by Gin Stephens. Gin Stephens is an intermittent fasting expert and best selling author of Fast, Feast, Repeat.

For more details, check out our guide to clean fasting.

Does It Break My Fast?

You may be wondering if certain foods or drinks break your fast. Check out the below guides to get all of your questions answered.

Intermittent Fasting Books

Here are some of the best intermittent fasting books:

For more information, check out our guide to the best intermittent fasting books.

Intermittent Fasting Apps

Using an app on your fasting journey can be super helpful! When you use an app, you can easily track your fasted hours and your eating hours. Here are the top fasting apps:

For more information on these apps, check out our guide to the best intermittent fasting apps. Another option is to use an intermittent fasting calculator.

Intermittent Fasting Hacks

Here are some intermittent fasting hacks to make fasting easier and help you maximize weight loss results.

Drink Apple Cider Vinegar Before Eating

When you break your fast and before you eat, drink 1 tablespoon of apple cider vinegar mixed in a glass of water. Drinking apple cider vinegar before you eat helps to flatten your glucose curves.

Consuming 1 Tablespoon of apple cider vinegar before you eat cuts the glucose and insulin spikes of your meal by 20%.

This is an intermittent fasting hack because it leads to feeling fuller longer, it reduces cravings, it helps us lose and maintain weight and it helps balance our hormones!

Use Natural Appetite Suppressants While Fasting

You are bound to get hungry or feel hunger pangs while fasting. To eliminate those feelings, you may consider using a natural appetite suppressant while fasting. Here are some natural appetite suppressants you may consider:

  • Add a pinch of salt to your water
  • Drink green tea

By the time you utilize these natural appetite suppressants, you will notice your hunger fading and it’s easy to move on with your fast.

Fasted Workouts Can Increase Fat Burning

If you want to speed up your results, consider adding fasted workouts to your routine! When you workout in a fasted state, research shows that you induce higher fat oxidation than a fed state.

Research shows you’ll burn more fat when you do aerobic exercise in the fasted state than when your body does not have circulating nutrients to use for energy. One study found that when people ran on a treadmill in a fasted state, they burned 20 percent more fat compared to those who had eaten breakfast.

This is because your body doesn’t have readily available energy from food, so your body has to look elsewhere and pull from stored body fat.

For more fasting hacks, check out our guide to fasting hacks.

How To Make Fasting Easier

Here are some tips to make your fasts easier.

Stay Busy

Keep yourself busy! It’s much easier to fast when your mind and body is busy and not thinking about food.

Ideas on how to stay busy

  • Clean your house
  • Find a new hobby
  • Read a book
  • Spend time with friends
  • Go for a walk
  • Take a bath
  • Watch a movie or show
  • Play a game

Schedule Things During Your Fast

Schedule appointments, meetings, shopping trips, errands, etc. during your fast. When you are busy and on-the-go, fasting seems like a breeze!

For more tips, check out our guide on how to make fasting easier.

What Is Autophagy?

Autophagy is the body’s way of cleaning out damaged cells, in order to regenerate newer, healthier cells, according to Priya Khorana, PhD, in nutrition education from Columbia University.

The basic idea behind autophagy is that in the absence of external sources of food, the body begins to eat itself (auto: self, phage: eat), destroying and recycling its own damaged cell bits and proteins, so that new and healthy versions can be built. Autophagy is believed to be essential for helping protect against diseases like cancer and dementia.

Benefits Of Autophagy

There are so many amazing benefits of autophagy! Here are some of the benefits.

  • Protects the nervous system and the immune system
  • Protects against metabolic stress
  • Regulates cellular mitochondria, this improves energy production in the body
  • Encourages growth of new cells
  • Aides in healthy aging
  • Reduces risk of neurodegenerative diseases
  • Improves muscle performance
  • May help support a healthy weight
  • Improves skin health 
  • Helps your metabolism work better
  • May improve your quality and length of life
  • May assist in the prevention of cancer 

For more information on autophagy and how to activate autophagy, check out our guide to autophagy.

The Best Electrolytes For Fasting

Here are the best electrolytes for fasting:

For more information on all of these electrolytes, check out our guide to the best electrolytes for fasting.

The Best Coffee For Fasting

When picking a coffee to drink while you are fasting, make sure the only ingredient is coffee and check to be sure the coffee is unflavored.

Here are the best coffee options for fasting:

For more information, check out our guide to the best coffee for fasting.

The Best Teas For Intermittent Fasting

Here are some great tea options for intermittent fasting:

For more information, check out our guide to the best teas for fasting.

Why Am I Not Losing Weight On Intermittent Fasting?

If you aren’t losing weight on intermittent fasting, it’s typically a result of not following a clean fast, lack of sleep, not consuming enough water and high stress levels. If you want to lose weight on intermittent intermittent fasting, you need to follow a clean fast.

For more troubleshooting help, check out our guide on why am I not losing weight on intermittent fasting. You can also check out our guide on why am I not losing weight on OMAD.

The Best Intermittent Fasting Podcasts

Are you looking for inspiration on your intermittent fasting journey? Are you looking to learn more about fasting? Podcasts are a great way to inspire and educate!

Here are some of the best fasting podcasts:

For more information on these podcasts and other podcasts that discuss fasting, check out our guide to intermittent fasting podcasts.

Fasting Quotes That Will Motivate You

Need a little inspiration? Here are some fasting quotes to motivate you!

“Fasting is the single greatest natural healing therapy. It is nature’s ancient, universal ‘remedy’ for many problems.” – Elson Haas, M.D.

“Everyone who does intermittent fasting talks about it as a lifestyle, not a diet. They come for the weight loss, but stay for the health benefits.” – author unknown

“The best of all medicines is resting and fasting.” – Benjamin Franklin

“You’re not going to burn body fat if you’re eating.” – Dr. Jason Fung

“Eat a double whopper and no one bats an eyelash. Fast for 16 hours… Everyone loses their minds!” – author unknown

For more inspirational quotes, check out our round-up of the best fasting quotes.

Intermittent Fasting Statistics

  1. Fasting may be more useful than regular calorie restriction for many overweight patients because of greater loss of body fat, and better preservation of muscle. (PubMed)
  2. Intermittent fasting is seen as an inexpensive dieting option according to Americans. (YouGov)
  3. Restricting meals to a six-hour window that ended at 3 P.M. led to better insulin sensitivity and blood pressure even without weight loss. (Science Direct)
  4. Fasting may promote autophagy, a process in which your body breaks down and recycles old, potentially dangerous parts of your cells. (PubMed)

For more of the latest statistics, check out our round-up of intermittent fasting statistics.

Fasting Tips From Fellow Intermittent Fasters

Drink water or warm tea to curb hunger

Many people report the uncomfortable feeling of hunger late evening or in the morning. My suggestion is to drink water or warm tea. Warm tea soothes the stomach, can be a ritual and helps reduce any discomfort associated with the feeling of hunger. It is amazing how the feeling just goes away.

— Elena Mosaner, PCC, MS, CEO & Founder of HypnoCloud

Plan what you’re going to break your fast with

Plan what you’re going to eat when the fasting period is over. If you just run into the kitchen starving, you’re probably going to make bad choices! So whether it’s something you’ve prepped, or just a food that you have in mind, know what you’re going to break your fast with.

— Amy Oztan, Writer, Vlogger, Speaker at

Don’t eat for future hunger

Don’t eat for future hunger. If you are satisfied at the end of your eating window, don’t try to eat more “in case you’re hungry before your fast ends.” Eat for current hunger and leave it at that.

— Macy Michelle, personal trainer and wellness expert at Macy Michelle Blog

For more tips, check out our guide to fasting tips and tricks.

This article was a complete intermittent fasting guide.