Pros and Cons of Fasting and All You Need to Know

  • Fasting helps your body in more ways than none.
  • As with any diet, fasting has pros and cons, such as weight loss, better sleep habits, low blood sugar, high costs, and lack of guidance.
  • Fasting may be good for some and not for others.


If you have ever wondered if fasting is good for your health, then you should continue reading. Read more to know what fasting is, the pros and cons of fasting, and whether this is a practice meant for you.

What is Fasting?

Fasting refers to a diet in which the individual does not eat anything for a set period. Fasting can be an option for many individuals. It is good for those that have to fast for medical procedures or want to lose weight. In other cases, fasting can be a cultural or religious practice.

These days, fasting is a means to burn fat and restrict calories. But, it is not always for everyone. Below are the different ways to fast and how they can affect your body.

What are the Types of Fasting?


Intermittent Fasting

It is one of the most popular types of fasting these days. Intermittent fasting (IF) follows the idea that an individual will fast for a set number of hours a day. Then, they consume all their meals and calories in another set of hours. There are various types of intermittent fasting, and you can see them below:

  • 5:2: This method is also called twice a week and involves eating for five days, but then fasting for the other two. Some individuals do not fast all day for those couple of days. Instead, they severely restrict calories.
  • Alternate day fasting: As the name suggests, an individual alternates their fasting days during the week with this method. 
  • Time-restricted eating: This is the most popular method of intermittent fasting. An individual will fast for a set time, for example, 16 hours, and only eats all their meals for eight hours a day.
  • 24-hour fast: This method involves a fast for 24 hours.


Water Fasting

In water fasting, there is no consumption of any calories at all. That is also why it is also referred to as a “zero-calorie diet.” In most cases, individuals follow this fast in hopes of detoxing their bodies from toxins. Yet, there is no research to support this theory. It is very rigorous and has not shown to make a difference.  


Religious and Cultural Fasting

Fasting is a spiritual activity across many religions. Ramadan is a holy month for Muslims. They fast from sunrise to sundown for 30 days. Other religions refer to fasting during moments of spiritual growth and exploration.

When it comes to changing our eating habits, it is important to know what factors can affect our health and whether it is worth the risk.

Advantages of Fasting

Weight loss

As with other diets, fasting is an efficient way to promote weight loss thanks to a reduction in calories. Studies show that fasting in short-term periods may be an efficient way to lose weight. The weight loss is a result of limited meals and caloric intake. That said, it is most important to note what you are eating during the ‘eating window’ periods. Individuals who follow more nutritious meals during their “eating” hours, such as lean proteins, fiber, and vegetables, will likely see weight reduction.

Studies compared intermittent fasting to continuous dietary restriction (i.e. diets with no fasting periods). There was no difference between weight loss and body fat loss when there is equal caloric intake. Studies also show that fasting puts your body in a higher metabolism while there is no food or energy intake. By doing this, it forces your body to use the fat reserves as energy. Allowing your body to use fat for energy when fasting might lead to a reduction in weight and fat in the long term.


Reduction in blood sugar and high blood pressure

Calorie restriction has always been a strategy to reduce blood sugar and blood pressure. However, fasting is undergoing research in clinical trials as a method to manage health conditions, such as diabetes mellitus and cardiovascular disease.

Since some individuals focus on consuming fewer calories, they can lose weight and lower blood cholesterol levels. Individuals focusing on healthier and more nutritious meals during their eating period will see better blood glucose control. Ultimately, fasting can reduce insulin resistance. It is helpful for type 2 diabetes mellitus patients and those at risk for diabetes.


Antioxidant and anti-inflammatory

Much of the effects of fasting depend on how well the individual follows guidelines and eats healthy. Animal studies have revealed that fasting can be a way to protect your cells and brain from oxidative stress associated with diet. These studies were not performed on humans. It is unclear if the data translates to human health. Focusing on certain foods, such as dates, turmeric, ginger, and mushrooms, will also have an anti-inflammatory effect.


May reduce the risk for cancer

Even though studies are ongoing, preliminary data shows that fasting could delay the progression of tumors and cancer. For patients undergoing chemotherapy, a controlled fasting environment could result in better treatment outcomes. More data is needed in human studies to understand the effects of fasting on cancer and tumors.

May help control seizures and neurodegenerative conditions

Preliminary studies show that intermittent and controlled fasting could be a way to manage epilepsy and other neurological conditions. Also, the combination of fasting and consuming antioxidants can lead to better outcomes in neurodegenerative diseases like Alzheimer’s disease.

Disadvantages of Fasting



As with any diet that involves not eating at regular meal times, fasting can cause hypoglycemia in certain cases. Hypoglycemia is having low blood glucose, which can be dangerous and leads to severe issues, such as fainting, vomiting, and coma. For diabetics, the risk for hypoglycemia is much higher when skipping meals. If you have diabetes and would like to try fasting, consult your doctor, dietitian, or healthcare provider first to determine a safe plan for you.


Low electrolyte levels

For those taking medications, such as diuretics, blood pressure medications, and diabetes medications, there is a higher risk for low electrolyte levels. Electrolytes are essential minerals that help keep the fluid balance in the body. These include potassium, sodium, magnesium, and calcium. Studies show that long periods without eating or drinking fluids while exercising can lead to dehydration and low electrolyte levels. It can be dangerous for your heart, kidneys, and even brain.


Difficult to sustain

Fasting is not always easy, particularly around holidays and social gatherings. Without proper social support, an individual will likely feel isolated and depressed. Many social events are centered around eating. Without flexibility, an individual who is fasting might not want to attend or engage.

In other cases, fasting also requires more nutritious meals during eating hours in order to get in all your required nutrients. Nonetheless, this is not always possible for individuals that do not have access to fresh produce, lean meats, and other foods.


May lead to or reinforce an eating disorder

Since the focus of fasting is to restrict calories by not eating, it always focuses on food. For many individuals, this practice will likely exacerbate any eating disorders. In some cases, individuals that did not have an eating disorder are more prone to develop one, such as bulimia or binge eating disorder. For individuals suffering from an eating disorder, fasting is not recommended.


Not safe for children or pregnant women

Since children are still developing, it is never recommended to restrict their food intake. No studies have been done on children because fasting may not be a safe practice for them.

Pregnant women should refrain from fasting. It causes hypoglycemia, dehydration, and fatigue. It could even harm the developing baby.


Affects your mood

Fasting is not easy for everyone. While some individuals feel no hunger after a while, others are constantly experiencing hunger. These hunger pains could lead to fatigue, anger, frustration, and sleepiness. In the long term, fasting could affect how your body feels during long hours at work or during the day. In these cases, the safest practice is to limit the fasting hours.

Is Fasting Good for Your Health?

Fasting benefits vary from person to person. The medical benefits are not always indicated for everyone. Before you try fasting, check with your health care provider or registered dietitian nutritionist (RDN). This is particularly true for those that are:

  • Under the age of 18
  • Women who are pregnant or breastfeeding
  • People with diabetes, especially type 1 diabetes mellitus
  • Those who have a history of eating disorders
  • People without access to nutritious foods
  • Those who have nutritional deficiencies, such as anemia or vitamin B12

For best results, fasting has to be accompanied by meaningful changes. It means having a healthier diet that focuses on fruits, vegetables, fiber, whole grains, lean meats, and unsaturated fats. The meals that you eat during your eating hours will make the difference when it comes to the health benefits of fasting.

If you want to lower blood pressure, lose weight, lose fat, lower blood glucose levels, and improve insulin resistance, you will want to focus on the foods you eat during eating periods. Having guidance is key in the process. If you are taking medications, it is best to always check with your doctor.


When it comes to fasting, this dietary practice does not come without risks. While it has many health benefits and pros, it also has some cons. You can engage in fasting as long as you know what nutrients you need and you are eating well. There are times when fasting is good for you and others when you should not fast for long periods.


Fasting is a popular practice these days. There are various ways to fast and do it safely, and there are many pros and cons to fasting as well. This dietary practice is not for everyone, but it can be a healthy dietary habit for some.

Scientific Information

  • Antioxidant—compounds that help fight free radicals, chemicals, and harmful toxins that cause damage to the body. 
  • Hypoglycemia—this term refers to low blood sugar, usually below 70 mg/dl (number varies).
  • Electrolytes—these are minerals that your body needs to maintain fluid balance, pH levels, move nutrients in and out of cells, and keep your nerves and organs working well.
  • Diuretic this is a type of drug that causes the kidneys to make more urine. It allows your body to get rid of extra salt and fluid and treat other conditions, like high blood pressure.
Written by:
Juliana Tamayo, MS
Nutrition and Dietetics



Related post


Welcome to 7D VARIETY! We are delighted that you have decided to join our passionate community of writers. By agreeing to become a part of our community, you acknowledge and accept the following terms and conditions:

  • Personal Information Access: As a community member, you grant 7D VARIETY permission to collect your personal information, including name, contact details, and other relevant data for communication and content management. We are committed to ensuring the security and privacy of your personal information in accordance with our Privacy Policy.
  • Editing and Publishing of Articles: By submitting your content to 7D VARIETY, you grant us the non-exclusive right to edit, modify, and publish it on our platforms. We’ll make necessary edits for clarity, style, or grammar while preserving the integrity of your original work.
  • Copyright and Intellectual Property: By submitting content to 7D VARIETY, you affirm its originality and non-infringement of third-party rights. By agreeing to the terms, you grant 7D VARIETY an irrevocable, royalty-free license to use, reproduce, distribute, and display your content on our platforms and in related marketing materials.

By submitting this form, you signify your understanding and agreement to these terms and conditions.

Subscribe Now

to our newsletter to be notified and keep up to date
Dates filled with wallnuts
Thank you for subscribing to our 7DVARIETY Daily Newsletter
Trusted Source

PubMed Central

Go to source