Fasting Benefits By Hour, Metabolic Step-By-Step: Stages Of Fasting In The First 72 Hours Of The Fast

Fasting Benefits

Fasting Benefits

Updated on 5/18/2024
Martin AlvarezBy Martin Alvarez
Nutritionist/Dietitian Professional Guide
Learn More about Martin Alvarez

As a result of the recent meteoric rise in the popularity of fasting benefits by hour, the word "fasting" is no longer exclusively associated with religious observances or political demonstrations. Instead, it is now associated with a lengthy and impressive list of positive effects on one's health, including an improved mood, increased energy, enhanced focus, and even clearer skin.

Thus, it is unsurprising that you may be interested in giving fasting a try. You are a clever person, so as a first step, you want to gather as much information as possible on the effects that fasting will have on your body and how it will make you feel.

Because information is power, the following explains what occurs during lengthy fasts, including the fasting phases, what to anticipate throughout each step, and the rationale for these expectations.

What Exactly Is Meant By "Extended Fasting"?

Extended Fasting

Extended Fasting

There are a great many variants of the fasting method known as intermittent. Under some conditions, you will not break your fast for longer than 12 hours. And the 72-hour fast, which lasts for three days and is regarded as an extended fast since it is long enough to meet the criteria for such a classification, is the most extended period advised for casual, less experienced fasters. The consequences of a fast become more pronounced the longer it is continued.

In our lifetimes, most of us will find ourselves in situations where we are forced to go without food for 12, 16, or even 24 hours at least a few times. However, it is far less typical for individuals to go without food for three days unknowingly. In light of this, for this essay, we will concentrate on what a fast of 72 hours does to your energy levels, metabolism, and overall reaction.

Stage One Lasts For Twelve Hours

Glycogen, a stored form of glucose, is the primary and most preferred energy source for the human body. Glucose is a kind of sugar obtained from the carbs you ingest. During digestion, the carbohydrates you eat are broken down into glucose, which is then stored as glycogen in the muscles and liver of your body. As long as glycogen is stored in your body, it will be used to provide it with the energy it needs to carry out its functions.

Now, let's speak about hormones, shall we? After you eat, your insulin levels will increase, signaling your body to start breaking down glucose for energy. This will happen within a few hours. However, following a fast of twelve hours, your insulin level will begin to decline. Leptin, the hormone responsible for informing you that you are full, will also decrease, while ghrelin, the hormone that tells you that you are hungry, will increase. Fasting for 16 or 8 hours per day, or 18 or 6 hours per day, may help you achieve these Stage One advantages.

Stage Two Will Last For 18 hours

When you go without food for an extended period, your glycogen reserves will be depleted anywhere from four to eighteen hours later. When this occurs, your body will have no choice but to search for another source of fuel to use. After you have stopped eating for around four hours, your body will begin to generate energy via a process known as lipolysis. During lipolysis, the triglycerides, a form of lipid stored in your fat cells, are broken down so that they may be used as a fuel source. It will also get energy from breaking amino acids, the components that makeup proteins.

However, it will only keep you going for so long. Your body will enter a condition known as ketosis after abstaining from food for around 18 hours, which is when it will begin to depend on fat for its primary fuel source rather than glucose. Ketones are molecules your liver produces from fatty acids while your body converts fat into fuel, and these molecules are released into your bloodstream when your body does this process. At this point, your insulin levels will continue to be low, but your levels of glucagon, a hormone that regulates blood sugar levels, will begin to increase. This is done to prevent your blood glucose levels from falling too low. You may target these advantages of Stage Two using the 18/6 fasting method, the OMAD fasting method, or the Eat-Stop-Eat fasting method.

Phase Three: The First 24 Hours

After around twenty-four hours of abstinence from food, your body will start a fascinating process: it will begin to restore itself. This process, known as autophagy, is when your cells start getting rid of any components that are old, damaged, or working poorly. Autophagy is a term that comes from the Greek word for "self-eating."

It has been shown that autophagy may decrease inflammation, destroy cancer cells, and clean out the misfolded proteins suspected of causing Alzheimer's disease. Autophagy is a highly crucial process for maintaining good health. Because of the natural drop in autophagy that occurs with aging, researchers believe that inducing autophagy via fasting may be a strategy to delay the consequences of aging. In addition, several studies have shown that abstaining from food for some time is associated with a longer lifespan. These advantages of Stage Three may be attained by using the ADF (alternate-day fasting), the Eat-Stop-Eat fasting method, or the 5:2 fasting method. Read a comparison.

Stage Four: 48 Hours

Your body will enter a condition of long-term fasting around forty-eight hours after you first start a fast. As a direct consequence of this, a few things will take place. To begin, your growth hormone levels will dramatically increase, prompt quicker muscle repair, and assist in maintaining lean muscle mass. It is believed that this is connected to ghrelin, also known as the hunger hormone, which may stimulate growth hormone release.

Concerning the hormone ghrelin, its levels will continue to fluctuate throughout the day. Still, the peaks will go lower and lower, which indicates that your feelings of hunger will become more consistent as the fast progress. Consecutive fasting at a ratio of 5:2 may help you achieve these Stage Four advantages.

Fifth And Final Stage: 54 hours

When you've gone 54 hours without eating, your insulin levels will be at their very lowest. Your levels of ketones will continue to rise, and to keep your muscles from being broken down; your body will start breaking down branched-chain amino acids. It's important to point out the benefits of having insulin levels that are already this low. Diabetes is a condition that may be caused by insulin resistance, which can develop when there are elevated amounts of insulin in the body for an extended period. On the other hand, increasing insulin sensitivity, which occurs when you fast, may help you have a healthy body fat percentage, lower inflammation, and activate greater autophagy, all of which are advantages you have read about above. Consecutive fasting with a 5:2 ratio may help you achieve these Stage Five advantages.

Stage Six: The First Three Days

You will notice another advantage after you have completed your fast of seventy-two hours and have reached its conclusion. Your IGF-1 (insulin-like growth factor), a hormone that plays a role in growth and development, will begin to decline when you get to this point of your fast. This may stimulate the formation of stem cells, leading to the development of new immune cells and lower oxidative stress, all of which contribute to the delay or prevention of aging and illnesses such as cancer.

How To Stay Healthy During A Prolonged Fast

Extended Fasting

Extended Fasting

Fasting for more than 24 or 48 hours is a serious endeavor that should be done carefully and, ideally, under the supervision of a medical professional. It is important to note that extended fasting can have many positive health effects, but it is also important to remember that fasting for more than 24 or 48 hours is quite challenging. If you are interested in trying it, the following advice will help you remain as risk-free as possible throughout your experience.

  • Be sure to stay hydrated! Even though your body can survive without meals for up to three days, you should avoid depriving it of electrolytes for so long since they are necessary for keeping you hydrated. You may either ingest salt in your water or take an electrolyte supplement to maintain the levels of electrolytes in your body.
  • Create a strategy for how you will break your fast before you start. The most popular option is bone broth, which strengthens the immune system, reduces inflammation, and settles quickly in the stomach.
  • Talk to your primary care physician. In the end, the ideal person to help you through fasting benefits by hour is a medical specialist who can counsel you on your particular situation and provide advice.