Everything You Need to Know about Intermittent Fasting

Since intermittent fasting becomes increasingly popular because it’s been regarded to be beneficial for weight loss and health, you need to know about intermittent fasting in numerous aspects before starting it.

What is Intermittent Fasting?

Everyone is fasting every day but not everyone knows that.

Instead of focusing on what to eat, intermittent fasting focuses on when to eat.

Sticking to intermittent fasting also called IF, you are required to eat during a specific time only and stop eating during the rest of the time.

Based on the research made by Japanese cell biologist Yoshinori Ohsumi who won the Nobel Prize in Medicine in 2016 on how cells recycle and renew their content, a process called autophagy that is activated by fasting.

Fasting is thought to be a natural process because the diet mode intermittent fasting conforms to is similar to that of our ancestors who could suffer from hunger for a long time before finding something to eat. After all, there weren’t so many foods available as there are today and they couldn’t eat unless they found something to eat after hunting or collecting.

The core of intermittent fasting lies in the control that strictly regulates your eating and fasting time to provide the food you’ve consumed enough time to be metabolized to finally stop fat from being generated on your body.

For example, the most popular intermittent fasting model, 16:8, indicates fasters can eat whatever they want during the 8 hours of a day and don’t eat foods but can drink water or healthy beverages like black coffee during the 16 hours of a day.

Fasting isn’t a new term or a new lifestyle. Think of the word “breakfast” that is combined with “break” and “fast”. I believe you must have a better understanding of this word. Yes, your first meal in a day indicates a fact that you’re going to break a fast which means sleep because nothing will be eaten during your sleeping.

Therefore, the basic principle behind intermittent fasting is a natural process you conform to every day.

How does Intermittent Fasting Work?

There are numerous plans for intermittent fasting and all of them are based on regular eating and fasting schedules. For example, you can try the 16:8 window requiring you to eat during the 8 hours a day while fasting for the rest of 16 hours. Or, you can eat one meal a day and you follow that two days every week. It’s up to you to choose your favorite fasting diet mode.

Generally speaking, as you stop eating, your body will go through 6 phases.

Phase#1 (0-4 Hours). Blood Sugar Rises.

Depending on what you eat, your blood sugar begins to rise about 10 to 15 minutes after you eat and then remains at a higher level for about 4 hours. This is a normal body response after meals.

Phase#2 (4-8 Hours). Blood Sugar Drops

Hours after the meal, your blood sugar begins to decrease because the glucose from the food you ate was either used for energy already or stored for later use.

Phase#3 (8-12 Hours). Blood Sugar Settles Down

When your blood sugar decreases, your body releases stored carbohydrates for energy and to help stabilize blood sugar.

Phase#4 (12 Hours). Fat Burning

When your body stops burning food or stored carbohydrates, it needs to find another source of energy. During this phase, your body will burn fat to provide energy.

Phase#5 (13 Hours). Ketone Levels Rise

When your body fat is burning, the fatty acids will be converted into ketone bodies. As long as you continue through the phase, your ketone level will continue to rise.

Phase#6 (24 Hours). Autophagy

Autophagy, also known as cell clean-up, is the process of getting rid of cells that are damaged or dysfunctional.

The working principle of intermittent fasting is to prolong the time between your meals so that enough time is provided to burn your stored fat. Normally, most people have three meals a day and that doesn’t stop there. Sometimes, they consume snacks most of which are unhealthy, filled with sweeteners leading people to become fat.

What is Intermittent Fasting Diet?

The adjustment of the meal schedule is the basic requirement of intermittent fasting. For body healthy and weight loss, intermittent fasting diet should be followed as well because an inappropriate diet may break fasting easily.

What to Eat during Intermittent Fasting?

As an active faster, you aren’t allowed to eat anything during the fasting phase. When you end fasting, you can eat food during the eating phase. For weight loss and body health, the following foods should be consumed:


Proteins from animals and plants keep your muscle strength or even add your muscle when the suitable workout is implemented. If insufficient protein is available in your body, part of the weight you’ve lost maybe from your muscle. Therefore, you need enough protein to strengthen your muscle.

Fresh Fruit and Vegetables

Fruit and vegetables provide you vitamins and minerals that maintain and improve your health. Remember, food is what you fast for, not nutrients.

Healthy Fat

Fat is beneficial to your health unless it is healthy. The fat from sea fish, avocados, and nuts is just the healthy fat you need every day. Moreover, the omega-3 contained in those foods is beneficial to reduce the risk of heart diseases.

What to Avoid Eating during Intermittent Fasting?

Over-processed foods and foods containing high sugar or sweeteners should be avoided during intermittent fasting. Your fasting can be easily broken unhealthy foods such as a sundae or some cookies even though you’ve fasted for 12 to 16 hours.

What to Drink during Intermittent Fasting?

Intermittent fasting can be easily broken if you drink something that may break a fasting. While intermittent fasting, the following drinks are suggested for weight loss and body health:


Water is the best beverage while intermittent fasting. It contains 0 calories and keeps you hydrated. Moreover, water stops you from feeling hungry and feeling worried about the weight burden. If you think water tastes boring, add some slices of melon to make lemon water that benefits your body in lots of aspects.


“Can I drink coffee while intermittent fasting?” has been one of the most commonly asked questions. Yes, coffee can work with intermittent fasting as long as it’s black. A cup of black coffee contains 3 calories only. In addition, coffee helps you think, stopping your cognition from being damaged. If you don’t like the taste of black coffee, a little cinnamon is suggested.


In the process of intermittent fasting, green tea, black tea and oolong are acceptable as long as no high sugar is contained in them. Tea helps you with weight loss and provides you energy to live.

What to Avoid Drinking during Intermittent Fasting?

If the beverages you drink during intermittent fasting are rich in calories and sugar, they may easily break your fasting. Never believe the soda marketed as 0 calories can support your fasting since the sweeteners in it will cheat you.

What are Benefits of Intermittent Fasting?

Apart from weight loss, intermittent fasting has a lot of benefits.

Intermittent Fasting is Beneficial to Weight Loss.

Based on the discussion on the working scheme of intermittent fasting, it aims to expand the time between meals so that more fat can be effectively burnt. As a result, intermittent fasting is beneficial to weight loss.

Intermittent Fasting Simplifies Your Life.

Intermittent fasting provides you with a simple lifestyle.

For most people, three meals are quite a burden while they aren’t for fasters because they don’t need to spend much time thinking about what to eat next and how to eat. More time can be spent on things that are really worthwhile.

Intermittent Fasting Expands Your Life.

Based on the Honoring Clive McCay and 75 Years of Calorie Restriction Research by Roger B. McDonald and Jon J. Ramsey, a conclusion that rats with severely restricted diets lived up to 33% longer has been known. Therefore, a limit on calorie intake is beneficial to expand people’s lifespan, which is also where intermittent fasting stands.

As early as 1945, it was found out that fasting can expand rats’ lifespan. And this research further moves such a benefit of intermittent fasting to humans.

Intermittent Fasting May Reduce the Risk of Cancer.

This benefit hasn’t been solidly determined since there isn’t a lot of research or experiments leading to the straight correlation between cancer and fasting. However, early studies look active.

This case series report testifies that the side effects of chemotherapy can be reduced if intermittent fasting is done before that.

Intermittent Fasting is Easy to Carry Out.

Compared with most weight-loss methods, intermittent fasting can be easily carried out because you can start it at any time and any place. What you need to do is to resist your appetite during the fasting phase and prepare a fasting tracker to monitor your daily progress. When it comes to a weight loss plan based on the workout, you need to prepare a workout uniform and equipment. If you don’t have suitable equipment, you need to buy one or even directly go to the gym. Any link during this process can possibly stop you from going on. But intermittent fasting can be done at any time and place. Fasting can be done and ended similarly easily.

Intermittent Fasting Boosts Focus and Thinking.

Apart from weight loss and body health, some research indicates intermittent fasting boosts focus and memory. Breaking snacking habits is beneficial to focus on the work, which is one of the essential advantages of intermittent fasting.

What is Intermittent Fasting Schedule?

There are numerous intermittent fasting schedules compatible with the different demands of different people.


16:8 intermittent fasting schedule requires 16 hours of fasting and 8 hours of eating. Basically, one meal is abandoned when 16:8 is selected as an intermittent fasting schedule and which meal to abandon depends on the specific situation or individual demands. 16:8 is the most popular intermittent fasting schedule and is the start of the majority of fasters.


As you conform to 5:2 intermittent fasting plan, you’ll have five days of normal diet and two with 20% of the ordinary calorie intake. A research by International Journal of Obesity indicates that 5:2 intermittent fasting helps reduces more weight and fat compared with other intermittent fasting plans.

Warrior Diet

Warrior Diet is an intermittent fasting protocol developed by health and fitness author Ori Hofmekler. The warrior diet requires eating to be done in the evening. Fasters are allowed to eat only a few fresh fruit and vegetables and eat a big meal during the 4-hour window in the evening. Compared with other intermittent fasting plans, the warrior diet is stricter.


One meal a day, also called OMAD, is a fasting plan requiring one meal a day. It doesn’t specify what to eat or when to eat but you’re required to eat one meal only in a single day. OMAD is the highest fasting plan that is approximately 23:1 fasting. OMAD isn’t suggested for intermittent fasting beginners since it’s too hard.

How to Start Intermittent Fasting?

Go to Your Doctor First

Although intermittent fasting has been regarded as a useful way for weight loss and health improvement, it’s still important to ask for suggestions from your doctor. After all, everyone is unique and not all weight loss methods are fit for you. It’s both safe and professional for you to go to your doctor for advice before starting your intermittent fasting.

Start Intermittent Fasting in a Beginner Way

Never leap before you learn how to walk.

First fasters are suggested to start intermittent fasting from baby steps. You can start from an intermittent fasting plan for beginners such as 12:12 or 14:10. Or even you can keep your three meals unchanged only with snacking habit broken. I believe weight loss will be seen as well but it possibly takes a long time.

To easily and professionally conform to intermittent fasting, an intermittent fasting app is suggested so that you’ll be able to get the time to start fasting and eating. Moreover, fasting tips and resources will be provided to let you know more about intermittent fasting.

Is Intermittent Fasting Safe?

Based on the brief introduction on intermittent fasting, it’s been known that intermittent fasting has a lot of benefits to weight loss and immune system boosting. Generally speaking, intermittent fasting is overall safe.

However, it’s not fit for the following people:

Pregnant women or breastfeeding women shouldn’t conform to intermittent fasting until they’ve 100% completed pregnancy or breastfeeding.

That weight extremely low weight shouldn’t conform to intermittent fasting.

Old people shouldn’t conform to intermittent fasting because they possibly lack nutrients from the beginning.

Does Intermittent Fasting Have Side Effects?

All coins have two sides. Intermittent fasting has been regarded as a natural way of life since our ancestors did that, but it still has some possible side effects. The side effects won’t possibly occur to anyone, but you should know them before starting intermittent fasting because they’ll let you better follow it.

Intermittent Fasting May Make You Feel Sick

For different fasting time spans, fasters may suffer from headaches, lethargy, or constipation. Your body scheme may get challenged by a new lifestyle. Not everyone will suffer from those symptoms, but some will.

Intermittent Fasting May Lead You to Overeat

After finishing the fasting phase of intermittent fasting, you’ll possibly have a strong appetite for foods because your appetite hormone and the hunger center in your brain will possibly overrun so that you’ll possibly eat more than what you do generally even though intermittent fasting is being carried out.

Intermittent Fasting May Cause You to Easily Irritate

You possibly become irritated easily before you haven’t gotten used to intermittent fasting. Hunger brings irritation and it is the obvious result of intermittent fasting. Irritation only occurs at the initial stage of intermittent fasting and it’s mostly temporary.

Recommended Books and Sources on Intermittent Fasting

For more knowledge about intermittent fasting, the following books are suggested.

The Complete Guide to Fasting by Dr. Jason Fung

In The Complete Guide to Fasting, Dr. Jason Fung has teamed up with international bestselling author and veteran health podcaster Jimmy Moore to explain what fasting is really about, why it’s so important, and how to fast in a way that improves health. Together, they make fasting a therapeutic approach both practical and easy to understand.

The FastDiet by Michael Mosley

From Dr. Michael Mosley, author of The 8-Week Blood Sugar Diet, and Mimi Spencer comes a revised and updated edition of the #1 New York Times bestseller The FastDiet, complete with new science, recipes, and tips for easy fasting!

Eat Stop Eat by Brad Pilon

The Official Eat Stop Eat by Brad Pilon. Thousands of books have been written about the unique benefits of Intermittent Fasting and its ability to help people lose weight and improve health, but Eat Stop Eat was one of the first. Far from being just another fad, Eat Stop Eat is your indispensable guide to the latest science behind using intermittent fasting for simple yet effective weight loss, without unneeded complexity or the need to deprive yourself of the foods you love to eat.

Fastyle Blog

Fastyle Blog provides numerous knowledge about intermittent fasting and how to live a healthy life in a professional way. All the articles on Fastyle Blog are written in simple language and so easy to read that will definitely direct you towards a correct way.

Bottom Line

Intermittent fasting is an efficient way to lose weight and boost body health.

Intermittent fasting can be easily started and it can be done at any time and place.

There are different intermittent fasting plans, including 16:8, 5:2, warrior diet, OMAD, etc. to meed different needs.

You should ask for advice from your doctor before starting intermittent fasting.


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