The use of fasting to treat fevers is controversial. Eastern medicine thinks of fasting as increasing body fire, so that it might worsen fever. In actuality, when we consume liquids, we generate less heat, so this really helps to cool the body. With fever, we need more liquids than usual; with high temperatures and sweating, we need even more.

Some cases of fatigue will respond well to fasting, particularly when the fatigue results from congested organs and energy. With fatigue that results from chronic infection, nutritional deficiency, or serious disease, more nourishment is probably needed, rather than fasting.

Back pains that are due to muscular tightness and stress rather than from bone disease or osteoporosis are usually alleviated with a lighter diet or juice fasting. Many tight muscles and sore areas along the back may result from referred pain from colon or other organ congestion. In my experience, poor bowel function and constipation are fairly commonly associated with back pains.

Many patients with mental illness, from anxiety to schizophrenia, may be helped by fasting. The purpose of fasting in this case, however, is not to cure these problems but to help understand the relationship of foods, chemicals, or drugs to the mental difficulties. Allergies and hypersensitive environmental reactions are not at all uncommon in people with mental illness. Care must be exercised with the use of fasting in mental patients as the toxicity or lack of nourishment may worsen their problems. If, however, the patient is strong and congested, fasting may be indicated.

Obesity can be remedied by fasting. Obesity is the problem for which fasting is currently most often used (mainly protein drinks) in the traditional medical system, although it is not the best use of this healing technique. Fasting is not even a good treatment for those who are overweight; it is too temporary and may generate feasting reactions in people coming off the fast. Better would be a change of diet and a longer-term weight-release plan; something that will allow new dietary habits and food choices to replace the old ones. A short fast, perhaps of five to ten days, can be useful as a motivator and catalyst for making these necessary dietary changes and new commitments and to help release a pound or two daily.

Some very obese patients have been monitored by doctors while on water fasts done in hospitals for months at a time to shed weights of a hundred pounds or more. With other patients, the jaws have been wired shut so that they can take in only fluids drunk through straws. Newer fasting programs substitute a variety of protein-rich powders for meals. These are usually medically supervised programs for people who are at least 30-50 pounds overweight and make use of a prepackaged, low-calorie powder, such as Optifast or Medifast. This high-protein, low-calorie diet allows patients to burn more fat. These programs are not nearly as healthful as vital juice fasts, but they are nutritionally supportive over a longer time period and can be used on a outpatient basis fairly safely if people are monitored regularly. They provide all the needed vitamins, minerals, and amino acids to sustain life and help many obese people to lower their weight, blood fats, blood pressures, and blood sugars. However, as with any weight-loss program, if it does not motivate the participants to change their diets and habits, they then may stay in the "yo-yo" syndrome (weight going up and down and up), which may actually be more harmful than just remaining overweight.

A balanced, low-calorie diet with lots of exercise is still the best way to reduce and maintain a good weight and figure. Many obese people are also deficient in nutrients because they eat a highly refined, fatty, sweet diet. Often, these obese people are fatigued, and they need to be nourished first before they will do well on any fast.

Fasting to treat cancer is also a controversial topic. Many alternative clinics outside the United States use fasting in the treatment of cancers. Since cancer can be a devitalizing, debilitating disease, this may not be wise. Possibly with early cancer, and definitely as a cancer preventive to reduce toxicity, juice fasting may be helpful. Anyone with cancer needs adequate nourishment, and adding fresh juices to an already wholesome diet can help induce a mild detoxification and enhance vitality.

The Process and Benefits of Fasting
Although the process of fasting may generate various results, depending on the individual condition of the faster, there are clearly a number of common metabolic changes and experiences. First, fasting is a catalyst for change and an essential part of transformational medicine. It promotes relaxation and energization of the body, mind and emotions, and supports a greater spiritual awareness. Many fasters feel a letting go of past actions and experiences and develop a positive attitude toward the present. Having energy to get things done and clean up old areas, both personal and environmental, without the usual procrastination is also a common experience. Fasting clearly improves motivation and creative energy; it also enhances health and vitality and lets many of the body systems rest.

In other words, fasting is a multidimensional experience. Physiologically, refraining from eating minimizes the work done by the digestive organs, including the stomach, intestines, pancreas, gallbladder, and liver. Most important here is that our liver, our body’s large production and metabolic factory, can spend more time during fasting cleaning up and creating its many new substances for our use. Breakdown of stored or circulating chemicals is the basic process of detoxification. The blood and lymph also have the opportunity to be cleaned of toxins as all the eliminative functions are enhanced with fasting. Each cell has the opportunity to catch up on its work; with fewer new demands, it can repair itself and dump its waste for the garbage pickup. Most fasters also experience a new vibrancy of their skin and clarity of mind and body.

Initially, the reduction of calories allows the liver to convert glycogen stores to glucose and energy. Body fat can be used for energy (ATP) but it cannot generate or reform glucose; although many cells can metabolize fatty acids for energy, the brain and central nervous system need direct glucose. Proteins can be broken down into amino acids; of these, alanine and serine can be used to produce glucose. With fasting, some protein breakdown occurs, less if calories are provided by juices. When there is no stored glycogen left, our body will convert protein to amino acids and to energy. Fatty acids can also be a fair source of energy, usually after being converted to ketones. With total fasting, ketosis occurs as an adaptation by the body to prevent protein loss by burning fats. Still, protein and fats can be used to provide energy for brain cell function. With juice fasting, there is less ketosis, and the simple carbohydrates in the juices are easily used for energy and cellular function. The high-protein diets and fasts do burn fat and generate ketosis and weight loss, but they also add more toxin buildup in the body from the foods or powders used. Also, they do not rest and cleanse the digestive tract and other organs as well.

Fasting increases the process of elimination and the release of toxins from the colon, kidneys and bladder, lungs and sinuses, and skin. This process can generate discharge such as mucus from the gastrointestinal tract, respiratory tract, sinuses, or in the urine. This is helpful to clear out the problems that have arisen from overeating and a sedentary lifestyle. Much of aging and disease, I believe, results from "biochemical suffocation," where our cells do not get enough oxygen and nutrients or cannot adequately eliminate their wastes. Fasting helps us decrease this suffocation by allowing the cells to eliminate and clear the old products.

This physiological rest and concentration on cleanup can also generate a number of toxicity symptoms. Hunger is usually present for two or three days and then departs, leaving many people with a surprising feeling of deep abdominal peace; yet, others may feel really hungry. It is good to ask ourselves, "What are we hungry for?" Fasting is an excellent time to work on our psychological connections to consumption.

As far as fasting symptoms, headache is not at all uncommon during the first day or two. Fatigue or irritability may arise at times, as may dizziness or lightheadedness. Our sensitivity is usually increased. Common sounds like television, music, refrigerators may irritate us more now. The sense of smell is also exaggerated, both positively and negatively; I have had whole meals of smells while fasting. The tongues of most people will develop a thick white or yellow fur coating, which can be scraped or brushed off. Bad breath and displeasing tastes in the mouth or foul-smelling urine or stools may occur. Skin odor or skin eruptions such as small spots or painful boils, may also appear, depending on the state of toxicity. Digestive upset, mucusy stools, flatulence, or even nausea and vomiting may occur during fasting. Some people experience insomnia or bad dreams as their body releases poisons during the night. The mind may put up resistance, with doubt or lack of faith or a fear that the fasting is not right. (This can be influenced even more by listening to other people’s fears.) Most of these symptoms, however, will occur early if they do appear and are usually transient. The general energy level is usually good during fastings, although there can be ups and downs. Every two or three days, as the body goes into a deeper level of dumping wastes, the energy may go down, and resistance and fears as well as symptoms may arise. Between these times, we usually feel cleaner, better, and more alive.

The natural therapy term for periods of cleansing and symptoms is "crisis," or "healing crisis." During these times, old symptoms or patterns from the past may arise, usually transiently, or new symptoms of detoxification may appear. This "crisis" is not predictable and is thus often accompanied with some question by the fasters as well as their practitioners—is this some new problem arising or is it part of the healing process? Usually only time will tell, yet if it is associated with the fasting and one or more of the common symptoms, it is likely a positive part of detoxification. We should use the maxim of healing, Hering’s Law of Cure, to guide us—it states that healing happens from the inside out, the top down, from more important organs to less important ones, and from the most recent to the oldest symptoms. Most healing crises pass within a day or two, although some cleansers experience several days of "cold" symptoms or sinus congestion. If any symptom lasts longer than two or three days, it should be considered as a side effect or a new problem possibly unrelated to cleansing. If there is a problem that worsens or is severe and causes concern, such as fainting, heart arrhythmias, or bleeding, the fast should be stopped and a doctor consulted.