Fasting has long been practiced in many human societies, by many world religions. In Hinduism, it’s common to fast on Ekadashi, the 11th lunar day of each of the two lunar phases in a Vedic calendar month. Followers of Islam fast from dawn to sunset during Ramadan. Christians observe Lent, where followers don’t eat meat during the 40 days before Easter. Likewise, Buddhism, Jainism, Sikhism, Taoism, and Judaism have also followed fasting practices. In the past, good, substantial amounts of food was a luxury for many, not easily affordable. When it came to eating, most people had to stick to the basics. Certain items were available only for the festive season, so fasting inadvertently kept our ancestors healthy and disciplined as prescribed by the religions.

So, what is intermittent fasting? How is it different from the familiar idea of fasting? Technically, not so different, just a fancier name for it. So, let’s explore it in-depth! Intermittent fasting involves two periods: one when you eat (the eating window) and another when you start fasting (the fasting window).

Say you had breakfast at 10 A.M. and dinner in the evening around 7 P.M. That would be your eating window. Your fasting window opens after you finish eating your dinner by 8 P.M and stop eating until the next day. You’re in a fasting state until you have your next meal, whether it’s breakfast or lunch.

Do you realize that some of us already practice this daily, without being aware of it? Ideally, we all fast from dinner until breakfast or lunch. When we extend the fasting period slowly and steadily, that’s when the glucose in our bodies starts breaking down. Once the glucose levels start depleting, the body automatically switches to burn stored fats from our body. Then fatty acids called ketones are released into the bloodstream, which are beneficial to the body. So in many ways, intermittent fasting can truly help us tackle obesity and other health conditions!

Different Types of Intermittent Fasting

The 16:8 approach, where we’re in a fasted state for 16 hours and eat for about 8 hours. Sounds difficult? Let’s break it down and see! If we eat dinner at 7 P.M. and don’t eat anything else until lunch, or late breakfast, at say 11 A.M. The next day, we’d already be doing 16:8 type of Intermittent Fasting.

Likewise, if we have dinner at 7 P.M. and lunch at 1 P.M. (skipping breakfast) the next day, we’re taking the 18:6 approach to intermittent fasting. If you stretch it a little further and have dinner at 7 P.M. and lunch around 3 P.M. The next day, we’d be doing the 20:4 approach. The number on the left (16:8, 18:6, 20:4) denotes the number of hours spent in the fasted state, and on the right represents the number of hours spent in the feeding stage. As you can see in the example above, skipping breakfast isn’t always necessary, but it’s an option. Intermittent fasting can also be practiced if we eat breakfast and lunch and then skip dinner, or have breakfast and dinner and skip lunch. There’s room to play around here. It all depends on your schedule! We can begin intermittent fasting at the time suitable for us. The main factor here is the number of hours between the stages of fasting and feeding. 

One Meal A Day (OMAD) involves, as the name suggests, eating only one meal in a day. It can be either lunch or dinner. Simply start the meal with a salad, some fruit, or a smoothie, followed later by more solid food like grains, legumes, or bread. We can consume everything that we’d like to eat throughout the day in just one sitting.

There are other types of intermittent fasting called the 5:2 approach and Alternate Day Fasting (ADF). In the 5:2 approach, we can eat regularly for five days and just eat about 500 to 600 calories for the other two days. The fasting days can be consecutive. For example, if we eat 500 calories on Monday, eat regularly on Tuesday, and eat 500 calories on Wednesday, then we can eat regularly again for the rest of the week.

With ADF, we can eat regularly on Monday, fast on Tuesday, eat regularly on Wednesday, fast on Thursday, and so on. It’s important to consider that the fasting days have to be non-consecutive. It can be a daunting task if we’re trying it out for the very first time, but take it from those who have been fasting for a longer period, we can do this! It’s just a matter of allowing the body a few days to adjust and normalize the process. 

Fasting in general has many metabolic benefits. Before you decide on the approach that suits you best, try consulting with a medical practitioner or nutritionist to make sure you’re following the safest and healthiest approach for you.

Calorie Restriction VS Intermittent Fasting

Some people may think that intermittent fasting is the same as restricting daily calories, but it’s not. With an intermittent fasting regime, we can eat till our stomach is full. There are no restrictions on counting calories consumed in a meal. In a calorie-restricted meal, we may consume fewer calories on purpose. On the other hand, intermittent fasting is just tweaking when you eat, rather than what you eat. This makes us more attentive to the time gap we’re leaving between your meals than with your calorie intake.

The National Library of Medicine sheds light on this topic. Two groups experimented with an intermittent fasting regime and a calorie-restriction regime, respectively. After two years, the participants who did intermittent fasting without calorie restriction recorded better health parameters than those who consumed fewer calories. 

What Happens Inside Our Bodies During Intermittent Fasting?

The food we eat is converted into glucose and used as energy to run our body and do our daily activities. If calories aren’t immediately metabolized for energy, the body stores them as fat for future use. Sounds avoidable? No…Here’s why!

The fat is stored in the fat tissues as triglycerides. When the fasting window starts, the triglycerides are converted into fatty acids and glycerol, which can be an essential source for “energy and fat-soluble vitamins.” This is where our  liver chimes in – it has a vital function to convert fatty acids into ketones,  serving as fuel for many tissues, especially the brain, during the fasting period. 

You would think when we’re eating is when we’re least energetic, but the biology of our bodies beg to differ! There are fewer ketones in the body when we’re in the fed state, but there’s a considerable spike in the ketones when the fasting state starts. Within 8 to 12 hours of fasting, the ketones reach 0.2 to 0.5 mm, and they almost double by the end of 48 hours of fasting. So when we tell you your body was built to survive the toughest, we mean it! These ketones play a vital role in healthy cell and organ functions in our body. Ketones influence the expression and activity of many proteins and molecules, affecting health and aging.

Now Let’s Talk About The Holistic Benefits of Intermittent Fasting!

1. Reversal of Type 2 diabetes. Intermittent fasting can be a powerful way to help in the reversal of type 2 diabetes. Diabetes creates insulin resistance in the body, and intermittent fasting helps to reduce insulin resistance, thereby also helping to reduce the fasting glucose and fasting insulin.

2. Weight loss. As the body goes into a fasted state, depleting the glucose levels, it switches to the body’s fat reserve, helping the body lose weight. Intermittent fasting can produce clinically significant weight loss as well as improve metabolic health in individuals with obesity. An analysis by the University of Illinois  tells us all forms of fasting reviewed produced mild to moderate weight loss. Participants with obesity lost an average of 3% of their body weight, regardless of the time of the eating window. The study also showed that alternate-day fasting resulted in loss of 3-8% of body weight over three to eight weeks, with results at their peak at 12 weeks.

3. Anti-aging and longevity. When you fast, your insulin level is low, so the body switches to fat-burning mode; it needs the energy to keep the body functioning. In this process of using fat as fuel, the growth hormone (HGH) gets significantly boosted. This growth hormone is crucial to keep our muscle mass and bone density up to the mark, which prolongs the aging process. It may help us live a life free of many age- related complications, which can ultimately increase our lifespan.

4. Cognition and focus. Intermittent fasting enhances cognition in multiple domains. Balance and coordination also improves in animals on daily time-restricted feeding or alternate-day fasting regimens.  

5. Reduced inflammation. Experiments have been conducted to show that intermittent fasting reduces the release of pro-inflammatory cells called “monocytes” in blood circulation. Upon deep delving into this area, it was also discovered that, during periods of fasting, these cells go into “sleep mode” and are less inflammatory than monocytes found in those in the fed state.

6. Assists autophagy. The word autophagy comes from the Greek words “auto,” meaning self, and “phagein,” meaning to eat. In other words, to “eat the self.” This is a process carried out in our bodies since birth. Thousands of microscopic cells die with new ones taking their place daily. The autophagy process hinders the accumulation of toxins in cells, removes harmful cells and recycles dead cells. Eating in a time-restricted window can speed up autophagy and rid the body of waste and toxic cells, inhibiting certain diseases like Alzheimer’s and Parkinson’s. Studies on rodents have shown that alternate day fasting could reduce the occurrence of spontaneous tumors and could suppress many other types of tumors, allowing them to better respond to chemotherapy and radiation.

What Can We Eat in the Fasting Window? Let’s Take a Look!

In the fasting window, we can’t consume any solid foods; it’s ideally the stage of abstinence from food. Water, black coffee, and black tea are some go-to options. Bear in mind that it’s better not to consume drinks that may spike our insulin. The idea is to keep the insulin levels as low as possible for the fasting period to reap enormous benefits. Water, tea without milk or cream, and black coffee don’t contain significant calories, or anything that induces insulin in the body to digest it. So, sipping on tea and coffee could help you deal with hunger pangs at the beginning of the intermittent fasting regime.

Once the feeding window starts, is it okay to eat everything available to us? As far as possible, it’s essential to maintain a healthy diet during the feeding stage; it’s not recommended to consume everything in sight once we’re able to eat solid food. There’s no prescribed diet that we can follow here per se, but it depends on your choice, taste, and product availability in your region. 

Try to avoid highly saturated, sugary or bakery items in the feeding window. These foods may not positively affect the body or give the full benefits you’re looking for. In the first weeks, we can also feel dizzy, headaches, irritability, etc., but this gets better over time. In the beginning, for about two to three weeks, we may eat more than usual during the feeding window, but that is only natural. Once our bodies adjust, the hunger pangs fade away, and we start enjoying the process and seeing the results. A research journal featuring on the CellPress notes an overall improvement in health irrespective of what is eaten during the feeding window. But eating healthy is good for us, our environment, and our planet, wouldn’t you agree?

The 21st century has brought a lot of technological innovations, which helps with our creativity and can boost food availability and accessibility. We’ve been blessed by an abundance  of choices. We have far more milk and meat alternatives and types of bread and grains than we previously had! Today, we’re able to explore and enjoy delicacies from every culture in the world. Our immunity is at its lowest ebb. Many of us are all grappling with lifestyle diseases unknown to our ancestors. Is there a light at the end of the tunnel? Yes, definitely! Intermittent Fasting can help us lead the life we all strive for. 

Is Intermittent Fasting Restricted to a Specific Group of People?

People with medical conditions may need to consult their doctors before starting intermittent fasting. 

For example, pregnant women, breastfeeding mothers, or women trying to conceive may need advice from health practitioners. Or underweight individuals, kids below 18, or people who have eating disorders. Furthermore, people with diabetes and blood pressure problems may not be able to take it up independently.  

Now that you know how many holistic health doors intermittent fasting can help unlock, you can choose which approach you find most convenient for you – one that fits your health goals, as well as matches nicely with your schedule. Whether you’re opting for trying out the OMAD approach, or the 16:8, it’s preferable that you consult a professional beforehand, such as a nutritionist to ensure that intermittent fasting would be a safe practice for you.