Intermittent Fasting Guide: Fasting Types, Fasting Health Benefits, FAQs, and More

Fasting is nothing new to us. We, humans, have known it and practiced it for centuries, in some form or the other. As a hunter or a fruit gatherer, fasting was often done when there was a dearth of food. And it wasn’t unnatural. It seems our body has its own mechanism to deal with this state.

With time, researchers have started to believe that a certain duration of abstinence from food can actually work as a therapy and enable the body to heal itself.

A lot of fasting methods are practiced these days, and intermittent fasting is one of the most popular ones. In this article, we will be explaining what intermittent fasting is and the method by which it should be done.

What is Intermittent Fasting?

Intermittent fasting is an eating pattern where you cycle between fasting and eating if not feasting. This method is very much sustainable and has been shown to be beneficial to the body (1), (2), (3), (4).

There is no restriction on the type of food you chose to eat during your eating window, however, the time of eating is very carefully measured. While we go to sleep 1-2 hours after the last meal of the day and sleep for 8 hours, we have already reached the fasting state. When you extend it a little longer, you can very well be practicing intermittent fasting.

Remember when you are fasting, you can’t eat any solids. However, drinking water, tea, coffee, or anything which has zero calories is absolutely fine.

If you are taking supplements, you can very well take them. Just be sure it hasn’t any calories and doesn’t cause an insulin spike.

Types of Intermittent Fasting

There are different types of intermittent fasting. However, here we are going to jot down the three most popular ones.

1. The Leangains diet or the 16/8 method

This method involves fasting for 16 hours and eating during the remaining 8 hours. In this eating window, you can fit any number of meals you want. It can be two, three, or more and it is totally up to you.

It isn’t as hard as it sounds. You can simply skip your breakfast and be sure not to have anything after dinner. This particular method was popularized by Martin Berkhan, a fitness expert.

2. Eat-Stop-Eat or the Periodic Diet

As the name suggests, during this type of diet, you eat normally for a day and fast the next day. However, do not fast more than twice a week. It should be done between the days of normal eating and not on consecutive days.

It’s 24 hours fasting, and no solid food is allowed during this time. You can have drinks that do not contain any calories.

3. The 5/2 Diet or the Fast Diet

This diet was popularized by British Journalist Michael Mosley and is also known as the Fast Diet. During this diet, you are required to eat normally for 5 days of the week and restrict your calories for the rest of 2 days.

Men are recommended to take 600 calories and women to take 500 calories on those fasting days. However, no study really has confirmed the efficiency of the 5/2 diet, but of course benefits of intermittent fasting have been firmly established. 

10 Health Benefits of Intermittent Fasting (IF)

Intermittent fasting is very much in trend now and people are following it to lose weight. Is that the only plus point or there is more to it. Let’s know more about the benefits:

1. It Helps you Lose Weight

All kind of fasting including intermittent fasting is a great tool to lose weight. Fasting automatically results in a reduction in your total calorie intake that helps you lose weight (5).

In addition to that, intermittent fasting can work on your cellular and molecular level and help change your hormonal levels that facilitate weight loss (6), (7), (8).

IF lowers insulin, increases growth hormones and norepinephrine hormones that boost fat burning. These changes increase your metabolic rate and result in more calorie burn (9), (10), (11).

Less food on one side and high-calorie burn on the other side is a great way for weight reduction.

2. It Improves Insulin Sensitivity

Fasting for a prolonged duration can improve insulin sensitivity (12). This results in a drop in insulin secretion as your body works very efficiently with limited insulin. Studies state that lower insulin levels in the body make stored body fat more accessible to breakdown (13). This can help you reduce weight as well.

3. It Helps Reduce Inflammation

Inflammation is a condition where the body responds to an irritant. It’s the body’s way of fighting infection (14). However, too much inflammation is not good and can lead to various other diseases such as diabetes, multiple sclerosis, and many more.

Studies have confirmed that intermittent fasting helps reduce the release of ‘monocytes’, a type of white blood cell that is secreted as the body’s protection and indicates inflammation (15).

Another study confirmed that intermittent fasting helped lower oxidative stress in cells and lower inflammation (16).

4. May Improve Brain Power

Fasting is believed to help stimulate the production of a protein in the nerve cells known as brain-derived neurotrophic factor or BDNF. This not only makes neurons more resistant to stress but also plays an important role in learning, and memory (17), (18).

Fasting also triggers the process of ‘autophagy’, when the body removes damaged molecules and dysfunctional mitochondria and turns off the cell growth (19). Therefore, during fasting, neurons shift to a resource conservation mode and while eating it shifts to the growth mode (20).

5. Reduces Blood Pressure

The increase in the BDNF factor during fasting as mentioned above has been shown to effectively lower the systolic and diastolic blood pressure. This is mostly done by activating the parasympathetic system (21).

6. Increases Cell Turnover (Autophagy)

As mentioned earlier in connection to brain health, intermittent fasting initiates autophagy, which means self-destruction. It allows the removal of unnecessary and dysfunctional cellular components. This process protects our body from several diseases such as cancer (22), (23).

7. Increases Longevity

As has been mentioned in previous points, intermittent fasting can help reduce inflammation, lower blood pressure, increase insulin sensitivity, and initiate autophagy. All these together keep your body healthy and increase longevity (24), (25), (26).

8. Improves Heart Health

Intermittent fasting can reduce inflammatory markers in the blood, lower blood triglycerides, and the bad LDL cholesterol in the body regulates blood sugar levels and improves insulin sensitivity (27).

Homocysteine, interleukin 6 (IL-6) or C-reactive protein (CRP) are certain pro-inflammatory factors that can aid in the development of atherosclerotic plaque. Intermittent fasting can reduce the occurrence and promote a healthy heart which means longer years on planet earth (28), (29).

All these factors, together with the reduced formation of plaques can ensure a healthy heart.

9. Can Prevent Certain Cancer

Cancer cells are generally dependent on a nourishing environment for growth. They prefer a high-glucose level which is a primary fuel for most cells. Therefore, it is believed that fasting which leads to glucose depletion from the blood can alter or revert this effect. This can be a potential approach to cancer prevention or its effective treatment.

Fasting has also been shown to activate CD8 cytotoxic T cells and can modulate your immune system. A stronger immune system is very effective against any disease including cancer (30).

10. Can Slow Down Aging

Fasting makes your body more efficient at breaking down nutrients. It also improves the body’s ability to repair cells and DNA which slows down the aging process (32).

Intermittent fasting also reduces oxidative stress and improves the quality of life that slows down the aging process (33).

Frequently Asked Questions (FAQs) on Intermittent Fasting

1. Who should not do Intermittent Fasting?

People who have eating disorders or are underweight, should not try doing intermittent fasting. It won’t be helpful at all but definitely can be downright dangerous.

Certain studies have shown concern about women doing intermittent fasting. Some have shown irregular periods and some have feared infertility. These studies have mostly been done on mice and more research is being awaited.

2. Are there any side effects to Intermittent Fasting?

Side effects of intermittent fasting are headache, weakness, and irritation which are considered very normal as the body is getting used to the shift in metabolism. However, within 2 weeks to 1 month, the body gets used to this and the side effects disappear.

If you have any of these medical conditions it is advisable to consult your doctors such as diabetes, low blood pressure, pregnancy or breastfeeding, or have a history of amenorrhoea.

3. Can I workout while fasted?

You can definitely work out while fasting. It is a great way to reduce weight. However, sometimes it is recommended to take protein supplements such as branched-chain-amino-acid (BCAAs) supplements which can support your workout without taking you off your fasted state.

4. Are supplements ok to take while on Intermittent Fasting?

Yes, you can definitely take supplements while on intermittent fasting. But, there are some supplements that work better when taken with meals. These are iron, calcium, certain fat-soluble vitamins, and so on.

5. What is the right age to start Intermittent Fasting?

You should start fasting only when you are over 18 years of age so that it doesn’t interfere with your growth. Even then be careful and take the right advice and suggestions on how to go about it, and what to eat during the eating window.

Before you go…

Intermittent fasting is an eating pattern which cycles between a prolonged duration of fasting and an eating window period. In this window, you can have two or more meals without much restriction.

There are different ways by which you can do it.

Science has backed this strategy and has shown several health benefits. Intermittent fasting is highly effective in losing weight, reducing blood pressure, lowering cholesterol, reducing insulin resistance, and regenerating cells.

Practice it the way it best suits you.

About Tilottama Bose 48 Articles
With a Masters in Food Science and Nutrition, Tilottama has carved a niche for herself in the Health Writing Industry. She is passionate about helping her readers make informed decisions about the food they eat. She believes in the healing power of food and in food as medicine. Tilottama is an editor and writer at