How healthy is fasting 

Although fasting is making a comeback for its spiritual benefits, physicians and clergy alike say fasting is as good for the body as it is for the soul.

Fasting has a reputation as an alternative therapy practiced by chiropractors, nutritionists, and naturopaths. Joel Fuhrman, a family physician in Belle Mead, New Jersey, and author of Fasting—and Eating—for Health: A Medical Doctor's Program for Conquering Disease (St. Martin's Press, 1995), notes, though, that few, if any, doctors study fasting in medical school. And many patients would rather take a pill than do without food, Fuhrman says.

But fasting advocates tout its many health benefits. Fasting, something many people do routinely between dinner and breakfast, gives the body a rest.

A few health professionals claim fasting allows the body to heal itself from ailments such as asthma, arthritis, skin disorders, food allergies, hair loss, insomnia, and high blood pressure.

Within the first 36-40 hours of an extended fast, Fuhrman says the body switches to a protein-saving metabolism after using up glucose reserves in the liver. During a fast, about 90 percent of the body's glucose comes from fat stores.

Not all physicians agree with the healing potential of fasting. Reginald Cherry, a Christian physician in Houston and author of The Bible Cure (Creation House, 1998), agrees that fasting has positive health benefits and can prepare the body for a nutritional diet, but he has not witnessed any permanent physical benefits from fasting. Cherry says eating specific foods can assist healing. But he does not recommend fasting for weight loss because most fasters eventually regain most lost weight.

All fasters, particularly those with chronic health problems, should consult a physician before altering eating patterns. Pregnant women and young children should not fast.

A final trip to the all-you-can-eat buffet is not the best way to begin a fast. A fast should start slowly and end slowly, medical authorities say. Partakers should drink an increased amount of fluids and avoid caffeine, fat, and sugar. Doctors recommend avoiding medications and rigorous exercise while fasting, although moderate exercise, such as walking, is encouraged.

Some health professionals question the benefits of extended, 40-day fasts. "I think that is very risky," says Melodee Yohe, a registered nurse and managing editor of the Journal of Christian Nursing. Lengthy food deprivation causes the body to consume muscle tissue and can create an electrolyte imbalance, which can lead to arrhythmia and even death.

Still, Fuhrman contends most healthy individuals can fast two to three weeks with life-extending, not life-threatening, benefits. Electrolytes can become imbalanced after three weeks, Fuhrman says, which is why he recommends a physician's supervision.

Cherry regularly prescribes fasting for his patients, but he views it primarily as a spiritual tool. "I see patients fighting a battle, and they are at their wit's end," he says. After a three-day fast with prayer and water, Cherry says, "they really feel a closeness to God."