Fasting Limits & Extremes
The required daily intake human needs (of vitamins, minerals, fibers, proteins, carbohydrates, fats, water and other nutrients) does not amount to one pound of solid food plus adequate amounts of water, to stay active, healthy and alive, away from physical burdens, health hazards and functional disorders. Most humans can live on one meal a day, for life, as has been common since time immemorial among many species. However, some can go beyond such limit, by nature or practice.
Animals in the wild aren't so different from humans in their eating habits. They instinctively follow a variety of diets nature had taught them, depending on circumstance. They fast for hours or days when they can't find food, or graze all day when food is abundant. As humans, we can learn from, but not necessarily copy animals' behavior. Both fasting and grazing have their merits; yet there are stronger reasons to make the former choice.
Our body had developed an amazing storing ability over ages of evolution, long before we learned about freezing, drying, sterilization, and preservatives. It can store energy in different forms in its organs, muscles, fat cells, liver, and bloodstream; it stores many nutrients there too. When it can't find its needs outside, it looks inside. It had grown an adaptability to living completely independent of many such nutrients for long periods of time, and even for life.
Most people are initially discouraged from fasting by psychological or cultural reasons, not physical ones. As long as the human body gets a sufficiency of its fundamental nutrients, glucose and oxygen to burn it, its inner combustion engine will keep running. Even without oxygen outside, some can go without breathing for long times, slowly consuming the oxygen inside. The length of how we can survive without the rest of other nutrients depends on the facilities each one's "vehicle" is equipped with.
Grazing is promiscuous eating; it's a typically forward risk-taking animal behavior. Non-selective eating diversifies the benefits of food, just as polygamy diversifies our genes, yet it constantly exposes us to temptation, interference with one's duties, and distraction from other life priorities, causing problems, physical, psychological and social. Thanks to our civilization, unlike animals we humans can select our food in advance to get optimal benefit from it, by including in our meal all our body needs without having to take the time and risk of grazing. We can mindfully prepare and "wait" for our meal: we can fast.
The proclaimed benefits of continuous random eating in small portions all day long (picking) are scientifically doubtful, being incongruent with the way many animals have evolved, that had to fight and search for food everyday—a strenuous search that necessitated living without food for long hours and days fasting. Even when they had suffered dehydration, weight loss or organ damage, they could amazingly recuperate and heal fast afterwards.
The prime evil of the several-meal-a-day diet is its exposing humans to constant temptation and distraction by food whenever and wherever they go. To those who succumb, food can be their best friend, powerful master, and eventually invisible killer. Claiming that humans regularly need food is to ignore and deny many survival skills they latently possess. Understanding the human body by furthering research on its endless capabilities (e.g. of storage and energy consumption) can save us many physical burdens and time and energy tributes we daily pay to an unlawful master we are born to serve: our body, that has imprisoned for life the rightful master in its primitive cells—our mind. Human consciousness must be gradually freed, for nothing yet science has proven or found to support its out-of-body existence.
How long we can fast, completely abstaining from food and water, depends on the ability of our body to keep the basic nutrients and type of activity each of us does. For example, our body loses water quickly as it is consumed in metabolism and other inner reactions; and since some organs' functions are basically dependent on water, such functions, as well as the organs themselves in the long run will badly be affected by the lack of water, resulting in damaged kidney, cracked skin, swollen tongue, dysfunctional endocrine glands affecting mood and general brain functions, etc. Water is the number one nutrient all animals need; wherever water is, life can exist.
The durability of other nutrients may also vary dramatically. An example is the water-soluble vitamin C, that our body loses faster than many minerals and fat-soluble vitamins. Contrarily, our body keeps "iron" for several days in the bloodstream, that it won't matter if we skip our daily intake of iron for a day or two as long as we have enough of it in store. Sometimes, we may neither lose nor absorb a nutrient; rather, we save it, as is the case with glucose. The handiest source of energy, or fuel for our body to consume is the glucose in the bloodstream, being especially vital for many neural activities. Unlike vitamins and minerals, glucose burning is fundamental to keep us "just" alive.
Knowing the great value of glucose, Mother Nature had managed to store it in us, in different forms for later use. So when there is an insufficiency of blood glucose, the glycogen stored in the liver will do its job, with the assistance of adrenaline breaking it into a more consumable glucose form. If glycogen is not available or enough, nature moves on to the fat stored in the fat cells. If none is found, then to the protein of the muscles and vital organs ... The moment we run out of all energy resources, nature abandons us, leaving us to face our end alone.
For those with health problems, e.g. people on medication requiring them to divide their medicine into several doses taken with their meals, fasting—even for a few hours—is not advisable, since they must divide their daily intake of food too. Also if someone lacks any short-kept nutrients, it's not well-advised for them to fast either. However, for the rest of people, fasting is safe for much longer time. Even individuals in the above exceptions can fast whenever they have other prescribed alternatives that can last longer in their system, obtained from food or food supplements, or whenever the prescribed medicine or supplement can be taken without food helping its digestion, or when taken intravenously.
If eating is inevitable, and fasting is impossible, one can still control the quantity and quality of what they eat. It makes no sense to gorge oneself on a full, high-calorie meal, only to digest a small pill.
Most people can survive without food for a period between several days and several weeks, and without water for much shorter time than this—only few days. The difference in stamina varies widely between individuals. Some of those who went on a several-week food-and-water strike lost their tongue and feet before they died of severe dehydration. Others, like German fruitarian scientist Arnold Ehret, were reported to fast for several weeks. There are stories of individuals in Asian countries who are said to have fasted for months, years, or even all their life; but apparently these are local myths. However, fasting for a few hours everyday until sunset doesn't hurt.
Despite their undisputed ability to systematically fast for weeks, people who do that still go to extremes, harming their body, mind and life. After Ehret died there were different stories about his controversial death, the most probable of which is that his body's "lack of vitamins and minerals," particularly calcium, caused an immediate death when his feet slipped and his head hit the ground causing the fracture of his tender skull.
• In his lectures and writings, Ehret advocated a long fasting followed by fruit-only diet, believing the human body can live on fructose alone since we are but sugar-burning combustion chambers. Some scientists find such claim unfounded and over-simplistic.
• Another motive for advocating the extreme fasting lifestyle is the zeal of its adherents about nature and all that is natural (raw food, herbal medicine, etc.). Ehret was a nature-lover himself, whose works influenced naturalists and members of the back-to-nature movement, that flourished after Darwin's writings. He seemed to have replaced the human "passion for food" with the love of nature (as mentioned in his diaries about his long walks and biking trips), escaping food cravings to natural beauty.
He didn't take into account that nature-love can also become an addiction, creating such itchiness for travel and obsession with nature, while ignoring one's vital need for certain nutrients. The ancient wisdom considered eating, mating, walking ... as mere instincts basically needed for survival, that we shouldn't blindly follow because nature is not always the right guide. The same wisdom was later re-affirmed by neuroscientists, as shown in brain-scans of the primitive brain whose "poor" reasoning skills cannot be trusted while one is under the influence of food, sex, nature, or any natural or artificial drug.
• A third motive some extreme fasters have is disgust with food, as well as excrement. In defending the mucus-less diet Ehret suggests, he claims that excrement is a poison we should never keep in our body, as it can poison its entire systems. He didn't cite much evidence on that; rather, he kept "playing on" the natural disgust people feel toward the "subject" without explaining the many harms it supposedly has. In fact, the acid in our stomach is even more poisonous; yet we live peacefully with it.
• Ignorance also leads to irrational fasting, and some societies and religions praise living without food as a sign of spiritual superiority, confusing "what we wish to be, with what we really are" at this stage of evolution. Following millennia-old traditions of fasting or even superstitions that nobody questions has a similar cost to pay, like that of following nature.
• Long healthy fasting should only be based on facts, without following personal whims motivated by mere enthusiasm to do experiments on one's own body, turning oneself into a guinea pig that may not even survive to see the results of his/her self-experiments.
• They may do it to impress other people, shock society, and feel different, even if "different" means weaker, sicker ... or dead.
Fasting Trends & Traditions
Fasting has many physical and mental benefits more people now realize, although such benefits have been known for thousands of years, cherished and gained differently by people from different parts of the world.
• Some people follow a liquid-based fasting, or even a water-only fasting, under the supervision of their doctor to decide which type is best for their health. Other than avoiding the dangers of dehydration in food-and-water fasting, liquid/water fasting has the benefits of detoxifying the body, while giving a temporary sense of fullness needed in gradual fasting. Examples: diuretic metabolism-speeding drinks consumed in moderation, containing caffeine, catechin, capsaicin, etc.
• The one-meal diet is ironically designed to escape the temptation of food, as long, and as much as possible. People can delay their breakfast until their bed time, turning dinner and breakfast into one meal. They MUST do this in advanced stages of food addiction, so that there won't be a chance for further food craving after one has finished their dinner and is ready to sleep (in which case their dinner has to consist of a small fiber-rich meal slowly eaten, else they develop other health problems). It's a game, a race between sleep and hunger, where we let one instinct overcome the other. Many individuals who had tried all sorts of diets, yet failed, successfully sustained the dinner-only, one-meal-a-day diet, because it simply hit the nail on the head by treating the root problem: food temptation.
Many fasting programs in the US and India involve one afternoon meal with less solid food. This is the ideal timing of a meal, when both nature and human body are at the height of activity and heat, rather than starting one's day with a heavy body and dull brain, or going to bed with a full stomach. It's only a matter of time before the body overcomes any food cravings before and after meal time. Unlike pros, most beginners in fasting will falsely attribute their dizziness, fatigue, irritability and lack of energy to their body need for food. But, just like every addiction and habit we quit, these are only the "withdrawal symptoms," which are but temporary.
Some people, religious or not, prefer to fast until sunset, just like many monks still do, or like early Muslims and Sufis did. Modern Muslims mostly secularized Ramadan (like many Christians did Christmas), by eating immoderately, more than once after sunset. This is not a secular or religious behavior; it's a gluttonous one. A secular society is founded upon basic knowledge shared by all humans, not on every one's personal beliefs, tastes or compulsive urges. Harming one's body and mind by overeating is definitely inconsistent with any scientific knowledge, nor does it lead to "spiritual salvation." People who misunderstand fasting, degrading it to a roller-coaster of starving and binging, are missing its real benefits.
* * *
Most of the non-fasting diets, that focus only on changing the type and amount of food, have proven not successful or not alone successful. Neither has depending on exercise, which increases appetite to ferocious degrees. Their inefficiency lies in ignoring the addictive nature of food brain-scans have shown us. People easily become food addicts, in a society purposely procuring it. Food is a handy pill paralyzing willpower, best cured by escape. Run—for your life, health, happiness, and loved ones—if it matters.