When your empty stomach starts to growl and begins sending your brain every “feed me” signal it can, don’t be content to let your mind dwell on the fact that you haven’t eaten. If you make it through with an iron will that says no to your stomach, but doesn’t turn your mind’s eye elsewhere, it says more about your love for food than your love for God.
Many healers claim that fasting is a particularly useful therapy for Americans and for the modern lifestyle, subjected to heavy diets, overeating, and constant exposure to food additives and chemicals. Some alternative practitioners have gone so far as to estimate that the average American is carrying 5-10 pounds of toxic substances in their bodies, for which fasting is the quickest and most effective means of removal.
People can live days with no food and water, and weeks or several months consuming only water. In lab animals, when calorie intake is cut by more than 50 percent, they eventually die of complications from starvation. In the final stages of starvation, the body, depleted of glucose and fatty acids, turns to muscle protein for energy. Humans die when their body mass index (BMI) is around 12.
In addition to these, there is the fast of repentance which a person keeps after committing sin, it being imposed as a penance by the priest for seven days, forty days or one year. There is also a fast which a bishop keeps at the time he is consecrated. Also there are fasts that are widely observed but which have not been included in the canon of the church and which are therefore considered strictly optional such as the "Tsige Tsom" or Spring Fast, also known as "Kweskwam Tsom" which marks the exile of the Holy Family in Egypt.
One type of ketone flooding the brain is beta-hydroxybutyrate, or BHB. According to a paper published in February in Nature Reviews Neuroscience, BHB stimulates memory, learning and the cellular housekeeping process of autophagy in mice. BHB also triggers neurons, including those in the hippocampus, a memory center in the brain, to release what’s called brain-derived neurotrophic factor, or BDNF, a protein that is important for learning, memory and improved mood. CR doesn’t generate these levels of ketones because glucose stores are never empty.
Fasting isn’t merely an act of self-deprivation, but a spiritual discipline for seeking more of God’s fullness. Which means we should have a plan for what positive pursuit to undertake in the time it normally takes to eat. We spend a good portion of our day with food in front of us. One significant part of fasting is the time it creates for prayer and meditation on God’s word or some act of love for others.
Mattson points out that, from an evolutionary perspective, the brain power that fasting generates makes sense. Mammals typically go days without food, often hunting on an empty belly. Semi-starved animals with enhanced smarts and energy would be more likely to obtain food and live another day. “If you are that wolf or lion, now a week with no food, you better be able to focus your mind and concentrate on what you need to do to get food,” he says.
Whether a regimen calls for two fasting days a week or eating your meals in a smaller "window" of time in the day, all plans share a near-freedom from calorie counting, a big plus for weary food diarists. Once you have planned your fasting-period menu—say, a 500-calorie day of chicken and veggies—you're set. And in your nonfasting periods, you eat normal, healthy meals (even that steak!) without worrying about every bite.
In the religions of ancient peoples and civilizations, fasting was a practice to prepare persons, especially priests and priestesses, to approach the deities. In the Hellenistic mystery religions (e.g., the healing cult of the god Asclepius), the gods were thought to reveal their divine teachings in dreams and visions only after a fast that required the total dedication of the devotees. Among the pre-Columbian peoples of Peru, fasting often was one of the requirements for penance after an individual had confessed sins before a priest. In many cultures the practice was considered a means to assuage an angered deity or to aid in resurrecting a deity who was believed to have died (e.g., a god of vegetation).
Through the years, I have learned that many people in the church have never been taught about fasting and prayer, and many have therefore never fasted and prayed. As a result, they don't know why fasting and praying are important, what the Bible teaches about fasting, or how to fast. To many, fasting sounds like drudgery -- or a form of religious works. To others, fasting sounds extremely difficult. People tend to stand in awe at reports of those who have fasted for several weeks. When I hear about such fasts, I no doubt think what they think: If I fasted that long, I'd die! I couldn't possibly do that!
In a randomized trial of 107 overweight or obese premenopausal women, researchers found that participants who followed an intermittent food energy restriction plan (25 percent restriction two days a week) lost a comparable amount of weight to the participants who followed a continuous energy restriction plan. After six months, participants following the intermittent calorie restriction plan lost an average of 14 pounds each. Results were published in 2011 in the International Journal of Obesity.
Those studies above, in working with small sample sizes, and different types of fasting than recommended here, would lead me to believe that fasting affects men and women differently, and that many of the weight loss benefits associated with intermittent fasting (that affect insulin and glucose responses) work positively for men and negatively for women.
Fasting for Jews means completely abstaining from food and drink, including water. Traditionally observant Jews fast six days of the year. With the exception of Yom Kippur, fasting is never permitted on Shabbat, for the commandment of keeping Shabbat is biblically ordained and overrides the later rabbinically instituted fast days. (The optional minor fast of the Tenth of Tevet could also override the Shabbat, but the current calendar system prevents this from ever occurring.)
As researchers study the different fasting mechanisms to try to determine the ideal protocol for a variety of outcomes in a variety of populations, however, the general public must proceed by trial and error. That leaves dietitians such as myself concerned that the hype around fasting could encourage people to follow harmful plans that severely restrict nutrients, cause stress or unsuccessfully treat serious conditions.
The increase in longevity is also clearly associated with a decrease in disease states that would cut your life short, and calorie restriction is associated with a number of health improvements, including reduced visceral fat, reduced inflammation, lower blood pressure, and improved insulin sensitivity,5,6 just to name a few. Earlier research has demonstrated that calorie restriction helps extend the lifespan of animals by improving insulin sensitivity and inhibiting the mTOR pathway.