What Is Intermittent Fasting?

Updated on December 20, 2020

Today, intermittent fasting may be touted as one of the most popular fitness and health trends around the world. While many of you may have already reaped the benefits of intermittent fasting, for the uninitiated, it’s an eating plan that alternates between cycles of eating and fasting.  

Intermittent fasting is said to have several health benefits such as weight loss, better metabolism, protection against disease and slowing the aging process.  

In this article, we’ll discuss what intermittent fasting is, and how it improves your health. 

What Is Intermittent fasting? 

Intermittent fasting is an eating pattern by which you alternate between cycles of eating and fasting. It doesn’t focus on what you eat, but when you eat.

There are several methods for intermittent fasting, but all of them involve eating only during a specific time of the day or week and fasting for the rest. Most methods split the day or week into eating periods and fasting periods. Fasting for a couple of hours a day or eating one meal for a few days in a week gives your body adequate time to burn fat, and can have several health benefits.  

While many believe intermittent fasting is difficult to follow, it can be very simple and only requires small behavioral adjustments. Since we’re all fasting from the time we go to sleep until we wake up, intermittent fasting can be as simple as extending your fast until a few hours after you wake up.  

Most people start on the 16:8 method, where they skip breakfast and have their first meal around noon, and finish their dinner by 8:00 pm. This simple change in eating pattern can result in 16 hours of fasting and give you several health benefits. Alternatively, you may also choose the 5:2 method in which you fast two days a week having only up to 500 calories, and eat normally for the other five days. 

During the fasting period, no food is allowed. However, you may have coffee, water, green tea or any non-caloric beverage. You may also take supplements during your fasting window, given that they’re also zero calories.  

Intermittent fasting is known to provide several health benefits alongside weight loss. However, to understand how it works, you may have to ask an important question: ‘What is autophagy?

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Autophagy with fasting concept, renewal symbol on plate with knife and fork on green table cloth, top view

How Intermittent Fasting Works

To understand intermittent fasting, it’s important to know how your metabolism works. When you eat food, it takes up to three to four hours for it to be digested and absorbed. During this time, your insulin levels are high and you’re using your body’s sugar stores for energy. After this, your insulin levels are low but you’re still using glucose as your primary energy source for up to twelve hours of fasting.  

After hours without food, when your body has completely exhausted the stored glucose, your body starts to burn fat for energy. This metabolic change helps your body to use the fat that was inaccessible when your glucose levels were sufficient. Since most people don’t leave a gap of more than eight to ten hours between meals, your body rarely switches to burning fat. Instead, it’s almost always using glucose for energy. 

When your body starts to burn fat for fuel or when your insulin level goes down, your glucagon levels go up. Glucagon is a hormone that prevents your blood sugar levels from dropping too low and it also acts on your adipose tissues to breakdown fat for energy. Thus, with nutrition deprivation, your glucose stores are exhausted and your glucagon levels increase, promoting fat breakdown.  

This increase in glucagon further stimulates the process of autophagy. Autophagy is the body’s process of getting rid of old, broken-down cells when there’s not enough energy to sustain them. In autophagy, the subcellular organelles are destroyed and new ones are rebuilt to replace them. During autophagy, your body clears out old protein and cellular parts while stimulating growth hormones.

This process of autophagy helps to reverse the aging process, reducing the risk of diseases like cancer, and can alleviate symptoms of type 2 diabetes by lowering insulin sensitivity. It also acts against oxidative stress and inflammation, and is beneficial for cardiac health.


Simply put, intermittent fasting is a pattern involving alternation between eating and fasting. It’s all about when you eat, and not what you eat. However, if you’re trying intermittent fasting for weight loss, try sticking to wholesome, healthy meals; don’t shy away from fat, since you’ll come to use it as your main energy source.

While intermittent fasting is popular for the various health benefits it provides, it’s more of a lifestyle change than a fad diet. Incorporating intermittent fasting into your daily routine, you’ll not only lose weight in a healthy, holistic manner, but will also reverse the aging process. This means keeping your body fit and healthy for as long a time as possible.

The Editorial Team at Healthcare Business Today is made up of skilled healthcare writers and experts, led by our managing editor, Daniel Casciato, who has over 25 years of experience in healthcare writing. Since 1998, we have produced compelling and informative content for numerous publications, establishing ourselves as a trusted resource for health and wellness information. We offer readers access to fresh health, medicine, science, and technology developments and the latest in patient news, emphasizing how these developments affect our lives.