Fasting has gained popularity as a nutritional trend in recent years, but this is not a new practice. People from various religions and cultures have been following this practice for centuries.

Fasting offers numerous benefits like boosting metabolism, improving brain function and increasing weight loss. In this article, we will learn about the differing types of fasts, how to fast safely and its numerous benefits.

What is fasting?

Fasting is defined as the willing abstinence or reduction from some or all food, drink, or both, for some time. It is different from starvation. While starvation is involuntary, fasting is voluntary abstinence from food for spiritual or health reasons.

There is no standard duration for a fast; it can last from a few hours to days.

People fast for a variety of reasons like to detoxify, lose weight, to treat a medical condition and for religious beliefs. The type of fast that you choose should be appropriate for your health, body chemistry and any particular medical condition that you may have.

Types of fasting diets

1. Intermittent Fasting

Limiting your eating window for a fixed period and fasting for the rest of the day is known as intermittent fasting. An intermittent fast can range from 14 to 18 hours.

2. The 16/8 method

This method involves fasting for 16 hours a day and eating for eight hours. You can fit two or three meals during this eating window.

For example, if you finish your dinner by 8 pm, you should not eat your next meal before noon the next day.

You can drink water, coffee or other non-alcoholic beverages during the fasting period. Stick to healthy and nutritious meals during the eating window for the fast to be effective.

3. The 5:2 method

The 5:2 diet involves eating normally for five days in a week and restricting your calorie intake to 500 to 600 calories for the two other days. You can have two small meals of up to 300 calories on your fasting days.

4. Eat-stop-eat

This diet involves fasting for 24 hours, once or twice a week. If you finish your dinner at 8 pm one day, you should not eat another meal till 8 pm the next day.

You can go on fast from breakfast to breakfast or lunch to lunch, depending on your preference. Water coffee and non-alcoholic beverages are allowed during this diet.

6. Alternate day fasting

Alternate day fasting involves fasting every other day. You are allowed up to 500 calories of food on fasting days, and you can eat normally on the other days.

This method is not sustainable in the long term as it involves going hungry several times a week.

7. Warrior diet

The warrior diet involves eating small amounts of fruits and vegetables during the day and eating a huge meal at night. The diet also emphasizes that you eat whole, unprocessed foods that resemble what they look like in nature.

8. The Daniel Fast

Based on the experiences of Daniel in the Bible’s Book of Daniel, Daniel fast involves eating fruits, vegetables, and whole foods and avoiding meat, dairy and grains.

You should also avoid coffee, alcohol, and juice. Most people follow Daniel fast for 21 days.

7. Spontaneous meal skipping

This method does not involve a structured plan. You can merely skip meals from time to time when you do not feel hungry or do not have time to cook.

8. Juice fast

A juice fast involves only having juice from fruits and vegetables for a specified period. This type of fast needs some planning as you need to take a variety of liquids so that you get different vitamins and minerals in your body.

9. Cleansing fast

Cleansing fasts use drinks containing lemon juice, simple sugar, and cayenne pepper. People drink this liquid 6 to 12 times a day to cleanse the colon of food and toxins.

10. Partial fast

Partial fasts exclude a particular food like rice, wheat or meats from the diet.

How to fast safely

There are several different fasting techniques. Besides weight loss, fasting can provide many health benefits. However, if not done right, fasting can also be dangerous. Follow these tips to fast safely.

1. Health status

Consider your health status before you start a fast. Always check with a trusted medical practitioner before you embark upon a diet, especially if you are suffering from a health condition. In some circumstances, dieting can do more harm than good.

2. Duration

If you are not an experienced faster, keep the length of your fast short. Some people undertake long periods of fasting like 48 or even 72 hours, but this can increase your risk of problems.

Long fasting periods can lead to dehydration, irritability, hunger, mood swings, fainting and inability to focus.

3. Eat small meals

Some fasts involve complete removal of all foods during fasting days, while others restrict your calorie intake. The latter is a safer option as it reduces the risk of fasting like lack of energy and fainting.

The 5:2 fast allows 500 to 600 calories during fasting days, which is more sustainable in the long run.

3. Stay hydrated

Water is the most vital nutrient for the body. It is responsible for transporting nutrients and wastes throughout the body, regulating temperature and providing a medium for different metabolic processes. Dehydration can lead to thirst, headaches, and fatigue.

We get around 20 to 30 percent of the fluids for our body’s needs from food, so it is easy to become dehydrated during a fast without realizing it. So, you must drink at least eight eight-ounce glasses of water during a fast to stay hydrated.

4. Nutrition

While fasting is a useful tool for weight loss, you must ensure that you are getting enough nutrition to prevent health issues. A calorie deficit diet can lead to muscle loss in addition to weight loss (1). So, ensure that you eat protein on the days that you eat to minimize your muscle loss.

5. Don’t overeat of non-fasting days

It’s easy to binge on the days that you don’t have to fast. However, this could lead to bloating and make you lethargic. Additionally, it could also slow down your weight loss progress.

6. Eat whole foods

While fasting does provide many health benefits, it can only work if you eat healthy on the non-fasting days. Consume whole foods as like fruits, vegetables, fish, meat and eggs, as they provide wholesome nutrition.

These foods offer many health benefits like improved heart health and reduced risk of cancer (2).

7. Meditate

Fasting can be difficult as you may be tempted to sneak in a snack during the day. You can avoid breaking your fast by activities that keep your mind engaged and distract you from hunger. Mediation helps calm the mind and keeps you focused on your goal.

8. Mild exercises

While many people can maintain their regular exercise schedule during fasting, this can be tough for beginners. Begin with mild intensity exercises like walking, yoga, and gentle stretching.

9. Stop if you are unwell

Being tired, hungry and irritable is normal during a fast. However, if you are feeling ill, you must stop fasting. You must seek medical help if you feel weak and faint.

10. Eating disorders

People who have eating disorders should avoid fasting until they have dealt with their food issues. Fasting can lead to unhealthy eating habits if you are doing it for the wrong reasons.

Benefits of Fasting

1. Increases lifespan

According to a study from Harvard, fasting increases lifespan slows down aging and improves health by altering the activity of mitochondrial networks inside our cells.

The researchers found that the lifespan of worms can increase by preserving mitochondrial network homeostasis through dietary intervention (3).

2. Promotes blood sugar control

Several studies have shown that fasting can help improve blood sugar control. During a 2017 study, ten people with type 2 diabetes followed an intermittent fasting diet for two weeks.

The results showed that intermittent fasting lowered their blood sugar levels (4).

3. Boosts heart health

Incorporating fasting into your routine can be beneficial for heart health. According to a small study from the University of Illinois at Chicago, eight days of alternate-day fasting the levels of bad cholesterol and blood triglycerides by 25% and 32% respectively(5).

4. Helps in weight loss

Fasting is an excellent tool for weight loss. It helps to lose fat without sacrificing muscle mass, which is highly beneficial for athletes.

According to a study by the University of Southern California, when 71 healthy volunteers were placed on a five-day fast one in every three months, they lost an average of 6 pounds.

Their body mass index, blood pressure, fasting glucose also improved and there was no loss of muscle mass (6).

5. Improves brain health

Fasting helps improve brain function and prevents neurodegenerative disorders. According to one study by the University of Virginia, when mice were subjected to intermittent fasting for 11 months, it improved their brain function and structures (7).

Fasting helps relieve inflammation, which aids in preventing neurodegenerative disorders (8).

6. Helps prevent cancer

Studies show that fasting can also help prevent cancer. One study found that alternate day fasting can block tumor formation in rats (9).

Another lab study showed that fasting promotes differential sensitization in tumors and it can increase the efficacy of chemotherapy drugs in the treatment of cancer (10).

Final thoughts

Fasting is the willing abstinence from some or all food, drink, or both, for a limited period.

There are several types of fasting diets including intermittent fasting, warrior diet, Daniel fast, and cleansing fast.

The kind of fast that you choose should be appropriate for your health, body chemistry and any particular medical condition that you may have.

You must stay hydrated and eat nutritious food while fasting.

Besides weight loss, fasting helps improve heart and brain health, prevents cancer, promotes blood sugar control and increases lifespan.