What is Intermittent Fasting, and the Different Ways to do it

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Alternating between fasting and eating, following a strict timetable is called intermittent fasting. This seems to be the latest dietary lifestyle, gaining popularity among the masses because of being adopted by celebrities. Research has revealed that intermittent fasting is beneficial in managing weight and preventing certain diseases.

The question is, is intermittent fasting safe? What is the correct way to do it?

What Is Intermittent Fasting?

Intermittent fasting involves cycles or patterns of fasting and eating. You’re not supposed to starve yourself; instead, you cut back on the caloric intake for brief periods. Intermittent fasting is a practice to get your body used to feeling ‘full’ with small portions of food and eliminate the need to fill the body with junk and unhealthy foods.

Contrary to the other diets that focus on the what’s of eating, intermittent fasting focuses on the when.

Scientific Evidence of Intermittent Fasting

Fasting for a fixed number of hours or eating only one meal per week helps burn body fat. Mark Mattson, a neuroscientist from Johns Hopkins, spent 25 years researching the effects of intermittent fasting on the human body. He’s unearthed some interesting insights.

According to Mattson, human bodies can evolve to survive without food for hours and days and even longer than that. The cavemen hunted for animals and searched for edible berries, mushrooms, and nuts. In a way, they were the original intermittent fasters. They had to. They had no food on-hand as we do at all times. Hence, maintaining a healthy weight was easy for them.

Even our older generations’ sleep routines meant an early dinner before going off to sleep. No TV shows and internet browsing kept them awake and made them fill themselves with snacks. They exercised, and their meal portions were small.

With entertainment options available 24/7, we spend less time sleeping and more time in front of our screens, watching movies, browsing social media, playing games, and chatting with our friends. All these activities involve sitting for hours throughout the day and night. We cause more damage to our bodies by adopting a sedentary lifestyle, munching on snacks, and increasing our daily caloric intake.

Less activity and increased calories can quickly result in diabetes, obesity, heart disease, and other life-threatening illnesses. Research shows that intermittent fasting might be a helpful way to reverse this growing trend of filling yourself with additional calories.

What are the Different ways of Doing Intermittent Fasting?

You can follow any of these five intermittent fasting methods based on your preference:

1. Time-Restricted Eating

Beneficial for beginners, this approach requires occasional meal skipping. The 16/8 method requires a daily fast of 16 hours and an 8-hour window where you can fit 2 to 3 meals. People can choose to have whatever meals they want according to preference, hunger level, and time. It is essential to choose healthy options at each meal time.

2. The 5:2 diet

This diet requires healthy eating for five days of the week, fasting, and restricting caloric intake for the last two days.  

It is not compulsory to only fast on the last two days. People choose their fasting days as per their ease. Some people choose Mondays and Fridays to fast, giving ample time to pass between their two fasts.

On fasting days, women consume 500 calories, while men consume 600 calories.

Having at least one non-fasting day between your fasts is good practice.

3. Eat-Stop-Eat

Eat-Stop-Eat involves not having anything for 24 hours. People practicing this diet opt for a 24-hour fast once or twice weekly. They can have coffee, tea, water, and other calorie-free drinks while fasting. During the non-fasting days, people follow their regular eating routine. Following this practice controls the total calorie consumption but does not limit the food choices.

Fasting for 24 hours straight is challenging and can cause headaches, weakness, or general irritability. These effects lessen as the body gets used to following this eating regimen.

Before starting the 24-hour fast, people should start easy and begin with a 12-hour and then 16-hour fast.

4. Alternate-day fasting

People follow this diet fast every other day. This diet method has several variations. Some people completely avoid food on the fasting day, while others allow themselves up to 500 calories. On non-fasting days, people choose to eat whatever and as much as they feel.

According to a study, alternate-day fasting is beneficial for weight loss and maintaining healthy heart health. The study found that all 32 participants managed to lose an average of 11 pounds during a 12-week dietary period.

This type of fasting is difficult to maintain for longer intervals and is not suitable for beginners and people suffering from certain medical conditions.

5. The Warrior Diet

The Warrior Diet involves filling yourself with small servings of fruits and vegetables during a 20-hour fasting time during the day and eating one hearty meal during a small 4-hours window at night. People following this diet should incorporate proteins, healthy fats, and some carbohydrates in their one meal.

What can you eat while intermittent fasting?

Eating While Intermittent Fasting

While you’re in the intermittent fasting window, you’re still allowed to have water, tea, and coffee. Even though you’re allowed to eat everything during the eating window, the actual benefits of this diet only get visible if you make healthy meal choices. Replace high-calorie foods, junk and fried items, and candies with lean protein, leafy greens, whole grains, and healthy fats.

Advantages of Intermittent Fasting

Research has unearthed the following benefits of intermittent fasting

1. Memory Boost

According to multiple studies, intermittent fasting improves verbal memory in humans.

2. Heart Health

Intermittent fasting lowers blood pressure, improves resting heart rates, and helps control other heart-related ailments.

3. Physical Performance

With this diet’s fat-reducing abilities, physical performance and muscle mass significantly improve, provided the person following the diet restricts their fats and carbohydrate intake.

4. Weight Loss

Intermittent fasting helps lose weight and belly fat and prevents obesity.

5. Improved Tissues

Intermittent fasting improves overall tissue health and reduces tissue damage during surgery.

Is Intermittent Fasting Safe to Practice?

The most sought-ought reason for adopting intermittent fasting is weight loss. Addressing chronic conditions is a close second. People suffering from high cholesterol, irritable bowel syndrome, and arthritis have found it beneficial in helping them manage the symptoms. Even though it is mostly safe, intermittent fasting is not a good practice for everyone.

Before starting a dietary method or adopting any change in your eating schedule, you should always consult a nutritionist or your primary care provider.

Who Should Not Practice Intermittent Fasting?

The following people should not try intermittent fasting:

  • Children
  • Teenagers under the age of 18
  • Pregnant women and lactating mothers
  • Diabetic people
  • People with blood sugar issues
  • People with eating disorders


Even though Intermittent fasting seems to be a great way of losing weight and improving one’s health, it can have an adverse reaction if you adopt a strict dietary regimen without easing yourself into it. Consult a doctor if you suddenly feel lightheaded, have nausea, anxiety, headache, elevated heartbeat, or other symptoms after practicing intermittent fasting.