The Benefits of Fasting
This blog has not been approved by your local health department and is not intended to provide diagnosis, treatment, or medical advice.
"Everyone has a physician inside him or her; we just have to help it in its work. The natural healing force within each one of us is the greatest force in getting well. Our food should be our medicine. Our medicine should be our food. But to eat when you are sick is to feed your sickness." – Hippocrates
"Instead of using medicine, rather, fast a day." - Plutarch
Since the days of antiquity, our ancestors routinely fasted, abstaining from eating food and sometimes even certain drinks for prolonged periods of time. Hippocrates (460 BC-370 BC) and Plato (428-348 BC) discuss fasting in ancient Greek writings. Paracelsus (1493 to 1541), a Swiss physician, alchemist, and astrologer, considered along with Hippocrates to be one the fathers of Western medicine believed, “Fasting is the greatest remedy—the physician within”.
Most who fast do so intentionally, but sometimes not. When a person is ill, for instance, the body might “force” a fast. Think about the last time you had an infection such as influenza or perhaps an intestinal illness. Chances are, you also had no appetite. The loss of appetite during an illness or injury is the body’s attempt to restore balance to help regain health while present pathogens are literally starved to death as the body’s repair mechanisms go to work full force.
Often fasting was chosen by our ancestors, for spiritual reasons in most cases, in an attempt to “purify the soul” or reach a higher “state of being or awareness”. Recently, science has shown us that fasting does in fact have benefits for the mind as well as the body. We have all experienced how overeating, the opposite of fasting, can have a dulling effect on the mind. Further, animal studies over the last few decades have shown that calorie restriction, which occurs during fasting periods, can help with weight loss.
Beyond shrinking waistlines, fasting and calorie restriction can also help increase one’s lifespan according to scientific studies. This occurs, according to scientists, due to activation of SIRT1 and SIRT2 genes. These genes make proteins that slow down the aging process. In other words, instituting the practice of fasting may actually help you live longer and achieve better health.
Benefits of Fasting and Calorie (kilocalorie) Restriction
- Weight loss
- Anti-tumor benefits
- Strengthens the immune system
- Increases longevity
- Reduced insulin production
- Increased adrenaline levels after about 24 hours, thereby increasing energy
- Improved insulin sensitivity (those with diabetes need to consult with their doctor before fasting as blood sugar will drop)
- Reduces inflammation in the body
- Reduces oxidation, or “rusting”, of the human body
- Improved mental health and reduction of depression and anxiety symptoms
There are various fasting programs out there, which will be discussed in this article. Fasting is the voluntary decision to not eat certain foods or drinks for a specified time period. Everyone fasts during the nighttime when they sleep (this is where the term "breakfast", or “break the fast”, originates). Those with diabetes and other chronic medical conditions should consult with their physician before initiating a fast.
Abstaining from all food or certain foods is required during a fast. Drinking of water, black coffee, and unsweetened tea is usually allowed, but recommendations may vary. When drinking water, consider adding lemon, strawberries, or cucumbers for extra flavor. Often, green tea may also be consumed and may help further weight loss goals. Some add chia seeds to their water to help suppress appetite.
Some types of fasts include:
- Intermittent Fasting
- Regular Fasting
- Partial Fasting
- Alternate-Day Fasting
- Juice Fasting
- Smoothie Fasting
This style of fasting is usually done to help with weight loss and/or to help improve blood sugar levels. When one does an intermittent fast, they should choose a six-to-eight-hour time period during the day to eat. For most, consuming meals between noon and 6 to 8 PM is best. Studies have shown that intermittent fasting can help lower cholesterol, triglycerides, and blood sugar levels. Some choose to consume a calorie-restrictive diet, paleo diet, or keto diet in addition to intermittent fasting in order to further assist with weight loss.
Avoiding all foods and calorie-containing drinks is referred to as Regular Fasting. This is essentially a water-only fast. Many who partake in this kind of fast do so for one, three, seven or 10 days to promote weight loss and detoxification of the body. No more than two liters of water should be consumed per day by most and drinking water in excess can cause electrolyte abnormalities. This type of fast should only be done under direct supervision of a physician.
A partial fast excludes certain foods. The most popular is an elimination diet where one eliminates meats and dairy products or other categories of foods. The Daniel Plan or Daniel Fast is an example of a partial fast.
Initially three weeks, this now six-week meal plan allows consumption of fruits, vegetables, whole grains, nuts, seeds, quality oils, and fresh water. It prohibits meats, seafood, dairy products, alcohol, sugars, fried foods, leavened bread (contain yeast), processed foods, caffeinated drinks.
Some choose to fast on alternate days. For example, on day one, they'll eat as they normally do, consuming about 2,000 kilocalories (In the United States, 1 kilocalorie=1 calorie), while day two, kilocalories might be restricted to 500. This is done in an alternating fashion, usually in the short term in preparation for other types of fasting programs.
This type of fast allows one to detox and lose weight. Most who choose a juice fast will practice anywhere from one to seven days. It is best to use a juicer and combine both fruits and vegetables to increase nutrients. This type of fast is rich in antioxidants, which helps the liver successfully eliminate toxins from the body.
Some prefer a Smoothie Fast over juicing, but like juicing, this type of fast allows one to also detox and lose weight. Most who choose a smoothie fast will do it anywhere from one to seven days. Combine both fruits and vegetables, use unsweetened almond milk or coconut water for antioxidant-rich smoothies—concoctions that contain only fruit are not advised, due to their high “sugar only” content. Therefore, it is important to add a whey or vegetable protein powder to help reduce the absorption of fructose. Adding peanut butter or almond butter is also helpful and adds protein. View more smoothie recipes.
Supplements to Take When Fasting
Whether fasting for health or religious reasons, there are supplements that can help maintain nutrient levels when food is restricted:
Branched Chain Amino Acids (BCAAs)
On June 19, 2002, a study in the Journal of the American Medical Association stated, “We recommend that all adults take one multivitamin daily….”. A quality multivitamin provides additional assurance that the body is getting what it needs, especially during a fast. Recommended dose: As recommended on the label.
Whey Protein is a common supplement used by those who exercise routinely and is frequently used as a meal replacement by those trying to maintain or lose weight. Derived from cow's milk, whey is also a popular source of protein by individuals attempting to build muscle. A whey protein shake can be used as a meal replacement with an Intermittent Fasting Plan or Alternate Fasting Plan. Whey is not advised with the Daniel Fast. Recommended dose: As recommended on the label.
A pea protein, meal replacement shake or vegetable protein powder should also be considered by those following intermittent fasting, alternate fasting, or partial fasting. Recommended dose: As recommended on the label.
Magnesium, a macro-mineral, should be taken if muscle cramps develop during the fast. Magnesium chelate (magnesium aspartate, magnesium citrate, magnesium malate) should be taken daily—125mg to 500 mg. If you develop loose stools, reduce your dose. A magnesium oxide formulation can also be considered, but it is not absorbed as well.
- JBI Database System Rev Implement Rep. 2018 Feb;16(2):507-547. doi: 10.11124/JBISRIR-2016-003248.
- Woolf, Eric C., Nelofer Syed, and Adrienne C. Scheck. “Tumor Metabolism, the Ketogenic Diet and Β-Hydroxybutyrate: Novel Approaches to Adjuvant Brain Tumor Therapy.” Frontiers in Molecular Neuroscience 9 (2016): 122. PMC. Web. 25 Jan. 2017
- Cheng C-W, Adams GB, Perin L, et al. Prolonged Fasting reduces IGF-1/PKA to promote hematopoietic stem cell-based regeneration and reverse immunosuppression. Cell stem cell. 2014;14(6):810-823. doi:10.1016/j.stem.2014.04.014.
- Fasting increases longevity in Laboratory rats https://www.sciencedirect.com/science/article/pii/S0047637400001093
- Clin Nutr ESPEN. 2018 Apr;24:14-21. doi: 10.1016/j.clnesp.2018.01.002.
- Fletcher RH, Fairfield KM. Vitamins for Chronic Disease Prevention in Adults Clinical Applications. JAMA.2002;287(23):3127–3129. doi:10.1001/jama.287.23.3127