Health Benefits to Fasting, but Proceed Slowly

Fasting to enhance your health is an ancient practice, supposedly recommended by Socrates, Plato and Hippocrates. Going without food for a prescribed period also has a rich spiritual tradition, while on a far less profound level assorted fasts or “detox programs” are popular in certain fashionable circles. It’s a controversial issue, so when I encountered a research study examining the effects of calorie restriction, I set off on my own quest for enlightenment on the health benefits of fasting. Here’s what I learned…


“Fasting is the single greatest healing therapy I know — with detoxification, it is the missing link in Western nutrition,” I was told by Elson Haas, MD, a specialist in family medicine, nutrition and detoxification and author of The New Detox Diet (Celestial Arts). Dr. Haas is founder and director of the Preventive Medical Center of Marin, an integrated health care facility in San Rafael, California. Dr. Haas says these practices help people feel more vital, creative and open to emotional and spiritual energies.

We discussed the different types of diets, including the fast, and talked about how they work. Most stringent, said Dr. Haas, is the “water fast,” which is exactly what it sounds like: no food, no juice, nothing but water — and he doesn’t recommend it. More than a day may in fact prove dangerous, though some spiritual disciplines continue to use it. Safer and more common is to diet by limiting yourself to the juices of fresh fruit and vegetables, as well as herbal teas, said Dr. Haas, noting this regimen has been popularized as calorie restriction and liquid-only diets. “Fresh juices are easily digested so the nutrients they supply are quickly absorbed,” he explained. “This kind of fast stimulates the body to clear wastes. Juice fasting is safer than water fasting, since it supports the body nutritionally while cleansing.”


Where previous animal studies have shown that calorie restriction boosts longevity, a recent series of research studies adds a bit of additional weight to the health claims by fasting advocates. Researchers at the University of California at Berkeley tested different kinds of fasts on mice, alternating between fast days and the non-fast (“feast”) days, when they could eat however much they wanted. Lead researcher Krista Varady, PhD, told me that certain fasting male mice showed reduced cell proliferation rates, including prostate cell proliferation, and reduced insulin-like growth factor IGF-1, which has been linked to various forms of cancer, including breast and prostate cancers.

There were four groups of mice, including a control group. One group was given nothing but water on alternate days… a second group got 50% of their normal caloric intake… and a third group ate 25% of their usual calories. The control group ate normally. Benefits correlated to fasting, with the most notably reduced cell proliferation rate seen in the most restricted — the water-fasters. But since all three test groups showed some reduction over four weeks, Dr. Varady concluded that “the research showed that you can consume about 25% of your food on alternate days — about one meal a day — and still get some benefit.”


Dr. Varady’s fasting mice did not eat any special food on their calorie-reduced days but humans on a “detox” program usually do — and should, Dr. Haas emphasizes. Like most other health professionals, Dr. Haas starts a detox plan by having his patients eliminate sugar, nicotine, alcohol, caffeine and chemicals (he calls it the “SNACC” program). After a week of this, he suggests following a simple diet consisting of one piece of fruit, one daily bowl (about a half-cup dry) of cooked whole grains (millet, brown rice, amaranth, quinoa or oatmeal), plus two to four heaping bowls of steamed vegetables eaten throughout the day — he calls this the “Detox Diet.” “People who are fatigued or just feel they need protein can add three or four ounces of fish, poultry or beans without any reduction of benefits,” he noted. This phase typically lasts a week or even two, and then people may slowly begin to add back more of their normal daily foods.

Other kinds of detox programs are variations of a juice fast, often involving a mix of vegetable juices and fruit juice smoothies, with optionally added protein powder. “Adding protein powder to your smoothies is especially important for those who don’t want to lose weight, for athletes who don’t want to lose muscle mass and for anyone with hypoglycemia or low blood sugar issues,” Dr. Haas said. It’s also okay to use milk made from rice, almonds or oats as a base for your smoothie, instead of fruit juice. Dr. Haas’ book features a basic formula for smoothies — one cup of liquid plus one cup of fresh or frozen fruit, plus whatever supplements you want or need to add, including ground flaxseed, wheat germ or fish oil. Also, he says he often adds green powders with grasses and algae.


As we were going to press, a paper was presented at the 2007 annual meeting of the American Heart Association in Orlando that seems to place another feather firmly in the fasting cap. Researchers examined the heart X-rays (called angiograms) of more than 4,000 male and female patients who participated in an ongoing study from 1994 through 2002, called the Intermountain Heart Collaborative Study. They found that members of The Church of Jesus Christ of Latter-Day Saints (Mormon faith) were significantly less likely to have coronary artery disease. Researchers have long known that Mormons are less likely to die of heart disease than the general population, but that’s generally been attributed to the fact that they don’t smoke. In this study, however, researchers controlled for the smoking factor and still found less coronary heart disease among Mormons. They devised a questionnaire to identify other healthy habits among the subjects and found that fasting was the strongest predictor of lower risk for heart disease. Mormons traditionally fast at least one day a month as part of their religion.


Fasting for the purpose of detoxifying is not without its risks — and should never be undertaken without medical supervision. This recommendation becomes all the more important as health challenges become more complex or profound. For instance, naturopathic physician Sonja Pettersen, NMD, told me that people who have been exposed to extremely toxic chemicals such as Agent Orange, for example, in Vietnam War veterans, may encounter difficulties with stringent detoxification since toxins remain stored in fat until they are pulled out by such a program. “These should only be released under medical supervision,” she warned. She also cautions that fasting is not appropriate for people with insulin-dependent diabetes, since it is so critical to keep blood sugar even.

While maintaining that commercial detox products are profit driven and are of limited general value, Daily Health News contributing medical editor Andrew L. Rubman, ND, agrees that “there are benefits of incorporating some principles of a restricted diet into your daily life.” His opinion is that strict and structured regimens are usually unnecessary, since maintaining a healthy system is really as simple as merely cutting back on a regular basis. “Reducing your caloric intake every other day — or even for a week or so — may allow your body to unburden itself a bit,” he said. He says that water-only and juice-only regimens should not be instituted unless medically necessary and supervised.

Because fasting, whether in the form of calorie restriction or for detoxifying, represents such a dramatic change from the way most of us eat, it can be a challenge. Best advice: If you want to give it a go, try it for a day or so and work up to a longer period. “Detoxification can be intense and it may temporarily increase symptoms of sickness for some people,” noted Dr. Haas. “But it can also be immediately helpful and uplifting.”

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