Fasting, a common part of the human experience throughout the course of evolution, holds the key to optimal health. Not only does fasting play a role in cultural and religious traditions, it also aids in weight loss, neural protection, cancer defense and more.

When we were hunters and gatherers, access to food could change on a day-to-day basis depending on weather, migration patterns, local flora and other factors. So, it is not a surprise that intermittent periods of fasting were prevalent in human history.

As society began settling down and becoming organized by agriculture, religions and cultures, food became more readily available. However, in the last few thousand years, fasting has become an important spiritual practice for almost all cultures around the world. Fasting marks important seasonal changes, times of sowing seeds or harvesting, preparation for ceremonies, initiation rituals, purification rituals and much more.

Fasting across cultures:

In Judaism, fasting is infused in many aspects of spiritual healing processes. Fasting is defined as the total cessation of all foods and drinks, which starts at sunset in the evening and continues through sunset the next day. Rabbi Arnold Bienstock explains fasting as a process of turning attention away from outward material needs and focusing on inward Spiritual processes.[1] Yom Kippur, the Day of Atonement, is the Jewish tradition that brings the whole community together in a communal healing and spiritually transformative process.

For Orthodox Christians, fasting is most commonly practiced during the 40 days of lent. Here, the definition of fasting involves giving up treasured foods or vices, such as meats, olive oil, chocolate or wine; while, fish is allowed in certain cultures. Father Anastasios Gounaris explains that the true intention is to, “devote the time, thought, and exertion dedicated to preparing and eating food to disciplines such as prayer, confession, worship, study, and almsgiving.”[1]

In Islam, the month of Ramadan is one of the most sacred celebrations of Allah. During this time, Muslims observe a complete fast from dawn to dusk. In the evening, families and relatives gather together to share a feast. It is explained that, during the time of fasting, attention is focused on gratitude for the Creator—the true provider of all of nature’s abundance. In our day-to-day routines, this abundance serves us most directly in the form of food.[1]

In the Hindu religion, many people fast at least one day per week, dedicating this effort to a patron demigod. The Indian culture upholds many ceremonies related to monthly moon cycles and seasonal cycles. These mark important transitions in work and communal activities. For example, Navratri, a nine-day festival dedicated to the Mother Goddess, is celebrated during April-May and again in September-October. This celebration of abundance and prosperity coincides with important times of sowing and harvesting food from the land.[2] These times of the year also represent major changes in seasons and climate.

The example of Navratri pulls together the practical and spiritual aspects of life, ceremony and health-care. While fasting honors Mother Earth’s efforts to provide us with nourishment, this celebration also encourages farmers to focus on sowing and harvesting as sacred duties. Those who are not farmers are called to celebrate their abundance through rituals. In spring and summer, our family sows seeds of wheat in a small pot to honor the Earth’s fertility. In the fall harvest time, mothers prepare a special bread that uses five types of flour to demonstrate the abundance and variety produced by the Earth. This bread is first offered to the Goddess, then eaten by the fasting family.

In the Native American tradition, vision quests are important initiation ceremonies for spiritual aspirants. In these traditions, the aspirants may wander, meditate or pray in the wilderness without consuming food or water for up to 4 days. This prolonged fast is done as a purification ceremony—a way to empty the body and allow the Spirit to fill it.

Fasting and health

The primary effect of fasting begins with changes to the body’s metabolic system. The most recent research suggests practicing intermittent fasting; this involves a full-day fast, one or two days of the week.

Fasting promotes the production of growth hormones that encourage the breakdown of fatty tissues—causing the body to use fat as an energy source.3,4 Growth hormones also promote the regenerative mechanisms that repair and heal. With fasting, resting calorie burning speeds up and the production of neurotransmitter norepinephrine elevates; these contribute to an increase in metabolic activity.[5] Norepinephrine encourages the liver and other cells in the body to use internal energy sources like proteins and fatty acids to produce energy. This influence on metabolic activity contributes to weight loss within weeks.[6]

Oxidation and Inflammation:

Fasting has been shown to increase oxidative stress at the cellular level.[7] The main source of this oxidation is the agitation of mitochondria—the energy producing center of the cells. In response to this oxidation, the body produces more antioxidants and rejuvenating compounds that support healing activity. In one study, researchers observed that fasting resulted in changes to gene expression that promoted anti-oxidant enzymes in the body.[7] In another study, subjects underwent alternate-day calorie restriction for 8 weeks. Researchers found that, while the inflammatory and oxidative signal increased initially, there was a significant overall reduction observed at 2 weeks that became progressively better during the 8 weeks of the study.[8] This is indicated by an overall increase in anti-oxidant and anti-inflammatory proteins in the blood stream.

Weight loss:

In the previous study, 8-week intervention with alternate days of calorie restriction also demonstrated significant benefits in energy metabolism and weight loss. Researchers found that subjects had a reduction in total cholesterol, triglycerides and LDL cholesterol; alternatively, HDL levels increased significantly during this period.[8] In this study, the reduction of oxidation and inflammation also correlated with weight loss. Weight loss from intermittent fasting is also associated with a significant reduction in the markers for heart disease: Triglycerides, LDL and C-reactive protein.[6]

Neural protection:

Autophagy is an important self-protective mechanism in the body. This process refers to the self-destruction of unhealthy cells in the body. This is initiated when a cell is injured or otherwise abnormal in function. The loss of autophagy in neurons is associated with an increased risk of neurodegenerative disease.[9]

A recent study demonstrated that short-term food restriction, like fasting, can increase the activity of autophagy. Specifically, more autophagy activity can be seen among cortical cells and purkinje cells in the brain; this activity benefits cellular cleansing mechanisms in the nervous system.[10] Cellular cleansing allows body the opportunity to replace or compensate for malfunctioning cells in the brain and other organs. Thus, intermittent fasting may protect from neurodegenerative diseases like Alzheimer’s and Parkinson’s disease. In one case series, 9 out of 10 patients with Alzheimer’s demonstrated improvements in cognitive activity by integrating intermittent fasting—going up to 12 hours each day without food.[11]

Anti-cancer activity:

Cancer cells are able to divide fast and uncontrollably. With this superpower, cancer cells compromise their robustness and resilience. As fasting increases oxidative stress and autophagy, it tends to put increased survival pressure on tumor cells. Studies demonstrate that, while short-term fasting can protect normal cells in mice and humans, cancer cells are unable to cope with the loss of the glucose fuel source.[12] Additionally, cancer cells become much more vulnerable to oxidative stress. The outcome? Fasting improves the effectiveness of chemotherapy by increasing sensitivity of cancer cells.

Studies on the effects of fasting on cancer found that intermittent fasting protects human cells against toxins and slows down tumor growth.13 Thus, normal cells are more protected from the damage caused by chemotherapy and radiation with the practice of fasting. On the other hand, tumor cells lack the same protective mechanisms; so, those cells die in greater numbers in response to chemo and radiation.

Similar benefits have also been seen among devastatingly aggressive brain cancers like gliomas. Researchers demonstrated how the integration of fasting with chemotherapy slowed down tumor growth significantly and improved survival time among animals with glioma.[14]

Fasting in Ayurveda

Every day of every week, we tend to put our digestion and metabolism under strain:

  • We eat when we’re stressed
  • We eat on the run
  • We overeat
  • We skip meals
  • We eat at irregular times
  • We eat bad food combinations
  • We eat heavy foods that are difficult to digest
  • We eat our next meal before our previous meal has digested
  • We eat too much, too late at night

Basically, unless we live a very peaceful, contained, strict or physically active life, caring for our digestion every day, at every meal, is a challenge.

As a result, it is somewhat inevitable that our digestive fire (referred to as Agni) will become imbalanced, in one of three ways:

  • It can get too hot and overcook our food
  • It can get too low and undercook our food
  • It can become erratic—sometimes hot, sometimes low—sometimes overcooking, sometimes undercooking

When our food is undercooked or overcooked, it creates undigested food waste or toxins known as Ama in sanskrit. For example:

  • Carbohydrates digest into simple sugars. But if carbs do not break down properly, it produces di-saccharides, which our bodies do not understand.
  • Similarly, digested proteins convert to amino-acids. If not properly digested, proteins become indoles and skatoles—very inflammatory and gene altering substances.
  • Fats are digested to fatty acids. Undigested fats will end up as arachadonic acid, which stimulate inflammation.

Undigested food toxins are collectively called AMA accumulates in our digestive tract and can eventually overflow into our channels and tissues, hampering cellular nutrition and waste disposal. Imbalanced Agni and accumulated Ama are considered the root cause of ALL disease in Ayurveda.

Normally, a healthy body is able to recognize toxins and dispose of them regularly, but an overwhelming response will put the body’s intelligence in jeopardy and activate disease—a phenomenon called Pragya-Apradh (mistake of the intellect) in Ayurveda.

Ayurveda divides us in different body types: Vata, Pitta and Kapha. Most of us are a combination of two and rarely three.

Vata dominant are low weight people with light bone structures and irregular appetites. Vata people feel cold easily, like warmer temperatures and prefer hot food and drinks. When out of balance, Vatas tend to experience hormonal disturbances, irregular energy, nervousness, anxiety, worry and insomnia. Dry skin, constipation, gas and cold hands and feet all indicate imbalance. Vatas need to be careful when fasting, as these people have low reserves and tend to burn out easily. Warm soups with vegetables, mung beans, meat or fish work well for Vata. Ginger is also a wonderful remedy; just add it to food or tea.

Pitta people tend to have medium physiques, greater digestive fires and large appetites. They have a hard time handling heated foods, hot spices like cayenne pepper, garlic, fried foods and red meat. Pittas are good speakers, who are prone to perfectionism, angry outbursts, irritability, skin rashes and inflammatory disease. Pitta dominant people can fast on vegetables, smoothies and broths.

Kapha people tend to have strong physiques, good muscle mass with exercise and a tendency towards weight gain as they have slow metabolisms. Usually, they have good stamina and strong immune systems when in balance. They are typically gentle, kind-hearted people. When out of balance, they tend to get overweight, heart disease, diabetes, allergies and depression. Water or herbal tea can be a really good method for fasting.

Ayurveda recommends that everyone should fast once a week. Even skipping one or two meals is beneficial. Ginger tea is good for almost every body type, as it kindles digestive fire and burns off AMA’s toxic buildup. Pittas can add cumin seeds, fennel seeds and coriander seeds. Kaphas can double up on ginger. For Vatas, try ½ to 1 teaspoon of ginger powder in tea. You can also sprinkle ginger powder and other spices on food. Cooking, however, will generally destroy all medicinal properties.

If you’re fasting weekly, choose a day that fits your lifestyle—when you are unlikely to be doing too much physical activity, socializing or super-demanding mental work. Skipping lunch on Mondays helps me detoxify.

Ayurvedic intermittent fasting or liquid diet days are an easy, effective habit for your ongoing preventative health regime. Not only does it reduce toxins and support a strong digestive fire, it also calms cravings so you tend to make better decisions. Here is a wonderful recipe for detoxification:

Ayurvedic Cleansing Soup Recipe

Here is a simple Ayurvedic cleansing soup, which cooks quickly. It will strengthen Agni, cleanse Ama and stabilize your blood sugar because it is low on the Glycemic Index. The quantities in this recipe can serve two people.


  • ⅓ cup basmati rice (1 cup = 250ml.)
  • ⅓ cup split moong dal with skin
  • 8 cups boiling water
  • 1 tsp. (tea spoon, 1tsp = 5ml.) ghee
  • ¼ tsp. turmeric
  • 1 pinch asafoetida or hing
  • 1 tsp. cumin seeds
  • 1 tsp. finely grated ginger
  • 1 tsp. garam masala (make your own – equal parts cumin, fennel, coriander and black pepper seed ground in a spice grinder)
  • Salt to taste
  • Lemon to taste
  • Coriander leaves to sprinkle on top (optional)


Soak your rice and moong dal overnight. In the morning, drain, rinse and put it in a large pot. Bring to a boil, then turn down to low heat and simmer until the moong is cooked. Serve hot with a sprinkle of salt, pepper, masala, a generous squeeze of lemon and ghee. Cooking time is approximately 20 to 30 minutes.

Cleansing is the key to your health

Drinking 6 to 8 glasses of clean, lukewarm water a day and doing breathing exercises will help you maintain perfect balance, along with good sleep, healthy digestion and elimination. Sleep is essential for the restoration and repair of the body and mind. Good digestion helps assimilation. Elimination is the key to immune health.

You cannot attain optimal wellness if one of these fundamentals is lacking. For total health, combine and maintain these practices regularly.


  • [1] Corn K. “Fasting and Feasting in Three Traditions: Judaism, Christianity, Islam.” Booklet 1, University of Indianapolis, 2006.
  • [2] Swami Sri Sivananda, “Hindu Fasts & Festivals.” The Divine Life Trust Society. Online edition, 2000; available at:
  • [3] Yo KY, et al. “Fasting Enhances Growth Hormone Secretion and Amplifies the Complex Rhythms of Growth Hormone Secretion in Man.” Journal of Clinical Investigation, 1988.
  • [4] Horne BD, et al. “Health effects of intermittent fasting: hormesis or harm? A systematic review.” Am J Clin Nutr 2015; Pg. 102:464–70.
  • [5] Zauner C, et al. “Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine.” Am J Clin Nutr 2000; Vol. 71, Pg. 1511–5.
  • [6] Johnstone A. “Fasting for weight loss: an effective strategy or latest dieting trend?” International Journal of Obesity (2015); Vol. 39, 727–733.
  • [7] Wegman MP, et al. “Practicality of Intermittent Fasting in Humans and its Effect on Oxidative Stress and Genes Related to Aging and Metabolism.” Rejuvenation research, Dec. 2014.
  • [8] Johnson JB, et al. “Alternate Day Calorie Restriction Improves Clinical Findings and Reduces Markers of Oxidative Stress and Inflammation in Overweight Adults with Moderate Asthma.” Free Radic Biol Med. 2007 March 1; Vol. 42(5): Pg. 665–674.
  • [9] Nixon RA. “Autophagy, amyloidogenesis and Alzheimer disease.” J Cell Sci 2007; Vol. 120, Pg. 4081-91.
  • [10] Alirezaei M, et al. “Short-term fasting induces profound neuronal autophagy.” Autophagy, Aug. 16, 2010; Vol. 6:6, 702-710.
  • [11] Bredensen D. “Reversal of cognitive decline: A novel therapeutic program.” Aging, Sept, 2014; Vol. 6(9), Pg. 707-717.
  • [12] Longo VD, et al. “Fasting Cycles Retard Growth of Tumors and Sensitize a Range of Cancer Cell Types to Chemotherapy.” Sci Transl Med. 2012 March 7; Vol. 4(124).
  • [13] Longo VD and Lee C. “Fasting vs dietary restriction in cellular protection and cancer treatment: from model organisms to patients.” Oncogene (2011); Vol. 30, Pg. 3305–3316.
  • [14] Safdie F, et al. “Fasting Enhances the Response of Glioma to Chemo- and Radiotherapy.” PLOSone, Sept. 2012; Vol. 7(9).