Skip to content

Get 10% on Your First Order claim now

75,000+ Worldwide Reviews
  1. DMoose
  2.  ⋅ 
  3. Nutrition

What Happens When You are Fasting? The Science and Benefits of Fasting

When you're fasting, your body is in a state of starvation. This means it starts to break down stored glucose for energy, which can lead to several health benefits.

Nicole Taylor
What Happens When You are Fasting? The Science and Benefits of Fasting
Table Of Contents

When you're fasting, your body is in a state of starvation. This means it starts to break down stored glucose for energy, which can lead to several health benefits.

Fasting has been shown to boost metabolism, increase weight loss, and improve insulin sensitivity. It can also help lower cholesterol and blood pressure levels, reduce the risk of heart disease, and help with other chronic conditions.

Fasting may be worth a try if you want to improve your health. Please consult your doctor beforehand to ensure it's safe for you. This article explores the science behind fasting to help you understand its impact on your body and uncovers its benefits.

What Happens to Your Body When You Fast?

When you fast, your body goes through several changes. Your blood sugar levels drop: When you don't eat, your body doesn't access glucose, its primary energy source. As a result, your blood sugar levels drop, and your body has to find another way to fuel itself.

Your body starts to break down stored glucose for energy: To prevent your blood sugar levels from dropping too low, your body will start to break down stored glucose (glycogen) for energy. This process is known as gluconeogenesis.

Your body also starts to break down fat for energy: As it burns through its glycogen stores, it will also start to break down fat for energy. This process is known as lipolysis. The combination of these processes leads to multiple health benefits, further discussed below in the article.

Types of Fasting

There are several different ways to fast, and the type of fast you choose will depend on your goals and preferences. Here are some of the most common types of fasting:

Intermittent Fasting:

Intermittent fasting is a popular way to control weight and improve health. There are many different ways to do intermittent fasting, but the most common is the 16/8 method.

This involves eating for eight hours and fasting for 16 hours. During the fasting period, you can drink water, black coffee, or tea, but you cannot eat any food. Intermittent fasting has many benefits, including weight loss, improved mental clarity, and decreased inflammation.

Alternate-Day Fasting:

It is a method of dieting that involves alternating between days of fasting and days of eating. For example, you might fast on Mondays and Thursdays and normally eat on other days. This type of dieting can be effective for weight loss, as it helps to create a calorie deficit. Additionally, it can help reduce hunger levels and improve blood sugar control.

However, alternate-day fasting is not suitable for everyone, and it is important to speak to a doctor before starting this diet. If you decide to try alternate-day fasting, start slowly and listen to your body, as it is important to avoid over-restricting yourself.

Whole-Day Fasting:

As the name suggests, whole-day fasting requires you to fast for 24 hours. This can be done once or twice a week, and there are many different ways to approach it. One popular method is to fast from dinner to dinner, meaning you would eat your last meal at dinnertime and then not eat again until the following day.

Another approach is to fast from breakfast to breakfast, skipping all meals in between. Whole-day fasting can help you lose weight, improve your metabolism, and lower your risk of chronic diseases.

The 5:2 Diet:

The 5:2 diet is intermittent fasting that has become popular recently. As the name suggests, you eat for five days and fast for two on this diet. There are a few different ways to approach the 5:2 diet, but one common approach is to normally eat during the week and then restrict your calories to 500-600 on the two fasting days.

Some people find this diet easy to cut calories and lose weight, as they only have to be careful about eating for two days a week. Others find the fasting days difficult and prefer a more gentle version of the diet where they eat less on the non-fasting days.

Benefits of Fasting

There are many different types of fasting, but they all have the same goal: to cleanse and detoxify the body. Fasting can provide many health benefits. Here are a few benefits of fasting that you should know about.

May Help Overcome Stress

When we fast, our bodies produce more stress hormone cortisol. This increase in cortisol can help us better tolerate physical and mental stresses. In addition, fasting has been shown to improve cognitive function and increase resistance to age-related diseases.

May Help Facilitate the Weight Loss Process

The human body is an amazing machine that can adapt to various conditions. One of the most notable examples is how the body responds to starvation. When food is scarce, the body has to find an alternative energy source.

The most common way for the body to do this is to burn stored fat for energy. This process can lead to weight loss, as well as some other changes in the body.

Reduces Inflammation:

Studies suggest that fasting can help reduce inflammation is linked to various diseases, including heart disease and arthritis. Intermittent fasting, in particular, is an effective way to reduce inflammation. This type of fasting involves alternating between eating and fasting periods, typically for 16 hours each day.

By reducing inflammation, fasting may help protect against several chronic diseases. Moreover, fasting can boost the immune system, making it an ideal way to stay healthy during cold and flu season.

Improves Gut Health

Research suggests that fasting can positively affect gut health. Fasting allows the gut to rest and repair itself, and it also promotes the growth of healthy bacteria. The benefits of fasting are thought to be because it helps clear out toxins and reduce inflammation.

In addition, fasting can improve digestion and reduce the risk of gastrointestinal diseases. While more research is needed to confirm these benefits, there is no doubt that fasting can be a helpful tool for promoting gut health.


It is the process by which the body breaks down and recycles damaged cells, which is essential for maintaining cellular health. Research has shown that fasting can increase autophagy levels, boosting cellular repair and cleansing.

Helps Control Blood Sugar Levels

One of the main benefits of fasting includes improved blood sugar control. When you don't eat, your blood sugar levels drop, which can help your body better manage blood sugar levels.

Enhances Heart Health

Fasting has been shown to improve insulin sensitivity, which can help reduce the chance of developing type 2 diabetes. Type 2 diabetes is another major risk factor for heart disease, so by improving insulin sensitivity, fasting may help to reduce the overall risk of heart disease.

While more research is needed in this area, the evidence suggests that fasting may be a helpful tool for protecting against heart disease.

Is Intermittent Fasting Good for You?

A growing trend believes that intermittent fasting is an effective strategy. Intermittent fasting should fast for 18 hours every day. It means not eating anything other than water and coffee during those two periods — but what does it mean exactly?

Intermittent fasting is when you cycle between periods of fasting and eating. The most common method is to fast for 16 hours and eat for 8 hours.

There is some science to back up these claims. A recent study found that intermittent fasting can help you lose weight, and another study found that it can help improve your insulin sensitivity. However, it's important to remember that these studies are small, and more research is needed to confirm the benefits of intermittent fasting.

So should you start intermittent fasting? It might be worth a try if you want to improve your health. Be sure to consult your doctor first.

Who Shouldn't Fast?

There are certain groups of people who should exercise caution or avoid it altogether. First, children and adolescents should not fast because their bodies are still developing. Fasting can interfere with average growth and development, so it's best to wait until adulthood to fast.

Pregnant women and nursing mothers also need to be careful with fasting, as it can lead to dehydration and malnutrition. If you are pregnant or breastfeeding, it's best to talk to your doctor before fasting.

Finally, people with certain medical conditions should avoid fasting, as it can exacerbate their condition. These conditions include diabetes, heart disease, and eating disorders. If you have any questions about whether or not you should fast, it's always best to speak with a doctor or healthcare professional.


1. What is the science behind fasting?

When you don't eat, your body doesn't access glucose, its primary energy source. As a result, your blood sugar levels drop, and your body has to find another way to fuel itself. Your body starts to break down stored glucose for energy.

2. How long should you do fasting?

There is no one-size-fits-all answer to this question, as the length of time you should fast will depend on your individual goals and health condition. However, fasting for 12-16 hours per day is an excellent place to start if you're new to fasting.

Fasting for longer than 16 hours per day may not be necessary or desirable for most people. And remember, it's always important to consult a healthcare professional before starting any fasting regimen.

3. What are the disadvantages of fasting?

Fasting has many potential disadvantages, including but not limited to the following: It can 

  • Cause fatigue and dizziness.
  • Lead to dehydration.
  • Can be dangerous for people with certain medical conditions.
  • Lead to an unhealthy obsession with food and weight loss.

4. Is it healthy to fast?

Yes, fasting can be a healthy way to detoxify the body and lose weight. When you fast, your body breaks down fat cells to produce energy. This can lead to weight loss and a decrease in inflammation.

Fasting may also improve cognitive function and increase lifespan. However, fasting is not suitable for everyone, and you should consult a doctor before trying it.

The Bottom Line

Even though fasting has been around for centuries, we are only now starting to unlock the science behind why it works. Your body goes through several changes that offer short-term and long-term benefits when you fast. From improved gut health to potential weight loss, there are multiple reasons for incorporating fasting into your routine. If you need help figuring out where to start, talk to your doctor to find out if fasting is right for you. 

Reading List

Article Sources

  • Albosta, Michael, and Jesse Bakke. “Intermittent Fasting: Is There a Role in the Treatment of Diabetes? A Review of the Literature and Guide for Primary Care Physicians.” Clinical Diabetes and Endocrinology, vol. 7, no. 1, Feb. 2021, p. 3. BioMed Central,
  • Aly, Salah Mesalhy. “Role of Intermittent Fasting on Improving Health and Reducing Diseases.” International Journal of Health Sciences, vol. 8, no. 3, July 2014, p. V–VI. PubMed Central,
  • Bagherniya, Mohammad, et al. “The Effect of Fasting or Calorie Restriction on Autophagy Induction: A Review of the Literature.” Ageing Research Reviews, vol. 47, Nov. 2018, pp. 183–97. ScienceDirect,
  • Johnstone, A. “Fasting for Weight Loss: An Effective Strategy or Latest Dieting Trend?” International Journal of Obesity, vol. 39, no. 5, May 2015, pp. 727–33.,
  • Welton, Stephanie, et al. “Intermittent Fasting and Weight Loss: Systematic Review.” Canadian Family Physician, vol. 66, no. 2, Feb. 2020, pp. 117–25.,
  • Li, Linghao, et al. “The Effects of Daily Fasting Hours on Shaping Gut Microbiota in Mice.” BMC Microbiology, vol. 20, Mar. 2020, p. 65. PubMed Central,
  • Mattson, Mark P., et al. “Impact of Intermittent Fasting on Health and Disease Processes.” Ageing Research Reviews, vol. 39, Oct. 2017, pp. 46–58. ScienceDirect,
  • Patterson, Ruth E., et al. “INTERMITTENT FASTING AND HUMAN METABOLIC HEALTH.” Journal of the Academy of Nutrition and Dietetics, vol. 115, no. 8, Aug. 2015, pp. 1203–12. PubMed Central,

Healthier and Happier Life is One Step Away.

Get information on health, fitness and wellness with our weekly newsletter.

Nicole Taylor

Nicole is a professional freelance writer specialized in sports nutrition and home based exercises. She publishes a website dedicated to home exercise and has contributed articles to magazines as well.

Start your fitness journey today!

Take an extra 10% off your order.

reach out

Toll Free: (833) 366-6733

5700 Crooks Road, Troy, Michigan 48098

*By submitting this form you are signing up to receive our emails and can unsubscribe at any time.