What Is Intermittent Fasting? A Detailed Beginner's Guide

What Is Intermittent Fasting (IF)?

Intermittent fasting (IF) is an eating pattern. It's a way to schedule your meals in a way you get the most nutrients out of them. IF is not technically a diet as it does not focus on what you eat but on when you eat.

There are various types of intermittent fasting available for you. The most common is fasting 16 hours daily or 24 hours twice a week.

Fasting is a part of the way life carrying out by humans since evolution. Unlike today, ancient hunter-gatherers didn't have supermarkets or refrigerators to access food throughout the year. There are times when they have to sleep on empty stomachs.

This makes a human capable of surviving without food for an extended period. Fasting occasionally or time-to-time comes more naturally to humans than eating 3-4 meals daily.

Fasting is also crucial in many religious texts, including Christianity, Hinduism, Buddhism, Islam, and Judaism.

That being said, intermittent fasting is a proven way to get lean without following any crazy diet or cutting back calories. Most IF plans allow you to eat the exact number of calories daily. Most diets revolve around eating bigger meals in a small duration.

How Does Intermittent Fasting Work?

Before we move ahead, let's learn about your body's fed state and fasted state.

Your body is in the fed state when it is digesting and absorbing the nutrients from the food you have eaten. This process starts when you start eating and lasts 3-5 hours. When you are fed state, your insulin level remains high. As a result, it becomes hard for your body to burn fat.

Your body enters into a post-absorptive state after a while. This state lasts 8-12 hours after your last meal.

After that, your body enters the fasted state. As your insulin levels remain very low, your body burns fat for energy.

We often snack or eat between the fed to the fasted state. Therefore, we rarely give our bodies a chance to burn fat. This is the reason why intermitted fasting has been practiced for centuries. It helps your body lose fat without changing the diet.

How Intermitted Fasting Changes Your Body?

Intermittent fasting makes several changes in your body on cellular and molecular levels. 

For example, your body uses fat as its primary energy source instead of protein. This helps you lose fat rather than muscles.

It also changes your gene expression and accelerates cellular repair. This means your wounds will heal faster.

Changes your Body Makes During Intermitted Fasting

  • Human Growth Hormone (HGH) − It boosts your growth hormone levels by five times the average. This encourages fat loss, muscle preservation, and gain.

  • Cellular Repair − Your cells trigger cellular repairs in the fasted state. This involves digesting and removing old and dysfunctional proteins and building new ones.

  • Insulin − it improves your body's insulin sensitivity. Your insulin drops dramatically, allowing your body to access stored fat to use as energy.

  • Gene expression − It makes specific positive changes in your gene expression. This adds longevity to your life by protecting you against diseases.

Health Benefits of Intermitted Fasting

The results are based on several studies on intermittent fasting conducted on animals and humans.

The Main Health Benefits of Intermitted Fasting Include

  • Weight loss − It helps you lose fat without any dietary restrictions.

  • Inflammation − It reduces inflammation, the key factor of many chronic ailments.

  • Insulin resistance − It lowers blood sugar by up to 6%, fasting insulin by up to 31%, and reduces insulin resistance. This protects your body against type-2 diabetes.

  • Cardiovascular health − It protects your heart by reducing bad LDL cholesterol, blood sugar, insulin resistance, inflammation markers, and triglycerides. 

  • Anti-aging − Studies on rats showed intermitted fasting to expand their life by 36-83%.

  • Brain health − It increases BFNF, a crucial brain hormone. This promotes the growth of new nerve cells, keeping Alzheimer's at bay.

  • Cancer − Some animal studies indicate IF protects against certain cancers.

Types of Intermittent Fasts

The 16:8 Diet

This method involves fasting for 16 hours daily and eating within the remaining eight hours. Most people follow this method by avoiding eating anything after dinner and skipping breakfast. You can eat between noon and 8 pm.

Eating chart −

  • Midnight-Noon − Fast

  • Noon − Eat your first meal

  • 4 pm − eat your last meal by 8 pm

  • After eight pm-midnight − Fast

However, if you do workouts in the morning, you should follow the 14:10 diet.

According to a study published in the Nutritional and Healthy Aging journal, 23 obese men and women follow this diet for 12 weeks. Those who follow the diet lose around 350 extra calories per day compared to those who eat on their regular schedule.

The 14:10 Diet

This diet is similar to the 16:8 method. However, you will have to fast for 14 hours and eat within a 10 hours window.

Eating Chart

  • Midnight-4 am − Fast

  • 10 am-12 pm − Take your first meal

  • 4 pm-8 pm − Take your last meal

  • 8 pm-midnight − Fast

Although it has a longer eating window, that doesn't make it any less effective than the 16:8 method.

In a 2021 study, people following the 14:10 diet eating nutritious food, and doing regular exercises lose more weight than followers of the 12:12 diet. 14:10 dieters also showed improvement in blood glucose levels after eight weeks.

Eat-stop-eat Diet

This method includes a complete fast for 24 hours once or twice a week. For instance, you can eat dinner at 7 pm on day 1 and go on a diet at 7 pm the next day. You must follow the schedule once or twice weekly, but not in a row.

Eating chart

  • Day 1 − Eat normally

  • Day 2 − 24-hour fast

  • Day 3 − Eat normally

  • Day 4 − Eat Normally

  • Day 5 − 24-hour fast

  • Day 6 − Eat normally

  • Day 7 − Eat normally

Make sure you are in sound health before going on this diet. This is because skipping food for a whole day could sometimes be dangerous. While the weight loss possibility may appeal to you, following this diet for the long term doesn't seem healthy.

The Warrior Diet

In this diet, you will eat a majority of food at night time. It involves eating a small portion of fruits and veggies during the day and consuming a large meal at night within a 4-hour window.

Eating chart −

  • Midnight-12 pm − Eat only a small amount of vegetables and fruits

  • 4 pm − Eat your last meal

  • 8 pm-midnight − Fast

This diet is more practical for most people due to its lenient fasting period. However, dieticians think it is less sustainable than the eat-stop-eat diet. This is because a small portion of food needs to meet your body's nutritional requirements. So it is easy to hurt your body or go on the overeating route.


Intermittent fasting can be a way to improve your overall health, reduce risk of disease, and even aid in weight loss if done correctly. It’s important to remember that intermittent fasting should be tailored to each person’s lifestyle and fitness goals. Always speak with a doctor before starting an intermittent fasting routine, or any new diet or fitness plan. Additionally, you should incorporate balanced meals and snacks throughout the eating window in order to ensure adequate nutrition and make sure you’re getting enough energy from your food. While intermittent fasting can have numerous benefits for many different populations, it is not for everyone so approaching with caution is also wise. Ultimately, it takes time to figure out what works best for you, so a trial and error approach may be the best way forward when trying out intermittent fasting one step at a time.

Updated on: 04-Apr-2023


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