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The Ultimate Cleanse? The Pros and Cons of Fasting, Plus a How-To Guide


Fasting is no new fad. The practice of fasting has been around for about as long as human civilization. But what is it, exactly, and why would anyone want to do it? Here is all you need to know about the practice of fasting:

What is Fasting?

Fasting is a broad term for any sort of abstinence from food, drink (besides water), or both for any period of time. It can be applied specifically, in an absolute cessation of all consumption of food or drink for a limited period of time. Or it can be a liberal definition for a partial limitation of certain foods or drinks for any period of time, even intermittently.

Essentially, the definition of fasting is determined by the metabolic state of the body after the complete absorption of a meal. Metabolic changes begin after 3 – 5 hours post-meal, and prolonged fasting is any fast that continues from 8 – 72 hours.

There are many reasons for fasting. Medically, the metabolic changes that occur can be necessary for diagnostic tests and observations, as well as therapy for various conditions. Additionally, it is a tradition in many cultures and religions. And there is a long history of fasting as a tool for political protest, non-violent resistance, or for spiritual enlightenment.

The Pros of Fasting

When done properly and safely, there are many benefits to fasting. Paracelsus is quoted as saying, “Fasting is the greatest remedy–the physician within.” Fasting has long been used therapeutically, for it’s rejuvenating and restorative powers, with a large boom in popularity around the 1930s when medical research began to discover the health benefits associated with limited periods of food restriction.

Tests utilizing intermittent fasting (fasting every other day) showed many positive effects, such as stress resistance, increased insulin sensitivity, reduced morbidity, and increased life span, according to the U.S. National Academy of Sciences. While no evidence of the benefits of fasting for cancer treatment has yet been found, according to the American Cancer Society, research has shown that it can improve the effectiveness of chemotherapy treatments. Other benefits have been observed in people observing extended fasts, such as the 30-day fast during Ramadan. Participants showed reduced LDL cholesterol levels and a positive effect on their lipid profile.

Physically, fasting gives the body a chance to rest and cleanse, allowing for greater healing. It focuses the body’s effort and energy not on digestion, but on repairing and detoxing its various systems. Mentally, fasting improves clarity, focus, and surprisingly, increases energy levels. Because the body is not spending an estimated 65 percent of its energy on digestion, it can do a little housekeeping, which clears up sluggishness in the body and brain. Creative minds have long claimed an increase in concentration and creativity that occurs during a fast. And spiritual leaders tout the clarity, enlightenment, and intuition that accompanies the practice of fasting.

The Cons of Fasting

While there are many positive benefits, fasting is not to be undertaken lightly. Pregnant or nursing mothers should never attempt a fast, as their bodies are under increased caloric and physical demands. Additionally, those with kidney or liver diseases, or those who are currently malnourished or anemic, have a weakened immune system, severely high blood pressure, medication-dependent diabetes, or other medical conditions should consult their doctor before attempting any fast.

Extended fasting can lead to electrolyte imbalance, thinning hair, as well as the downy hair associated with eating disorders. Prolonged fasting can also result in cardiac arrhythmia, renal failure, and starvation leading to death. Fasting while taking medications can cause dangerous complications.

While short term, or intermittent fasting has shown an increase in weight loss, long term fasting, or fasting with body dysmorphia is associated with mental conditions such as anorexia nervosa. The difference between fasting and starvation, according to Herbert Shelton, author of the book Fasting Can Save Your Life, is that fasting “is to abstain from food while one possesses adequate reserves to nourish his vital tissues; to starve is to abstain from food after his reserves have been exhausted so that vital tissues are sacrificed.”

How to Fast Safely

If you are interested and want to try a fast, there are many safe ways to reap the benefits. If you are nervous to start, consider this: the word breakfast is just that…the breaking of a fast that occurs overnight while we sleep. Our bodies are used to going without food for a small amount of time every night. Framing it in this light can help ease some of the worry associated with beginning a fast.

While water fasts can be beneficial (though in limited increments of time), partial fasts (that include juices, or small amounts of food such as fruit) are equally beneficial. If you are physically and mentally able to begin a fast, here are some tips on how to do it:

  • Begin by setting a small goal of fasting through one meal, such as breakfast. Observe your body, emotions, and thoughts. If you feel good, try fasting through lunch…if you still feel good try to make it to dinner and just like that, you’ve fasted for 24 hours!
  • Try intermittent fasting, or fasting every other day. On alternate days, eat as you normally would. Again, observe the changes that take place, mentally, physically, and emotionally.
  • Give a liquid, fruit, or mono fast a try. Juice or smoothie fasts that can provide all the benefits of fasting without completely abstaining from food and drink. Mono food fasts (where only one type of food, such a plain rice is consumed) or fruit fasts can be equally effective.
  • Try to reduce the density of your meals prior to beginning a fast. If you load up on rich, dense, calorie heavy meals, going cold turkey can be a real shock! Eat fresh, healthy, light, plant-based meals before undertaking any fast.
  • Set food guidelines, such as no eating after 8 pm, or drinking a full glass of water as soon as you wake up. Slowly training your body system like this can start up the body’s restorative powers, just like fasting, as well as make the transition into a fast a lot smoother.
  • Above all, notice how your body and mind shift during the process. There may be a period of irritably or sluggishness at first, but these symptoms will generally ease after a while and are mostly mental, due to the disruption of your body’s habits and expectations. Understand this is normal, but as always, the most important thing is to be observant and listen to your body. It is never advisable to fast with fear, resentment or anger.

By safely undertaking a fast, you can open your body’s healing and restorative powers, reboot your system, and create clarity in your mind and emotions. Have you experienced any interesting benefits from fasting? Please share your experiences below.

Image source: Jean Fortunet/Wikimedia Commons

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0 comments on “The Ultimate Cleanse? The Pros and Cons of Fasting, Plus a How-To Guide”

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Prof. Bryan
2 Years Ago

A true fast does begin until the 2nd or 3rd day using ONLY water.

During the first 24 - 48 hours after starting a water fast, the body is still burning off circulating blood sugar and sugar stored in the muscles and liver in the form of glycogen.

Ultimately, the "true" metabolic fast does not begin until we fully metabolize our blood sugar which takes approximately 2 to 3 days. The body then begins to burn fat tissue for fuel and molecules named ketones begin to flow in the blood circulation. Ketones actually suppress hunger and why fasting is not a difficult process.

To learn more about the Physiological Stages of Fasting, check this article out: http://www.fasting-retreat.com


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