Fasting and cleanses seem to be all the rage these days. Some people do it to give their digestive system a true reset. Others do it as a required preparation for a medical procedure. Still others fast to observe religious traditions—for example, Muslims fast from sunrise to sunset throughout the holy month of Ramadan. Maybe a few do it just to see if they can. And many apparently do it to lose weight quickly.
What exactly defines a fast? How long should you fast? For those who do it for health reasons, does fasting actually improve your health?
Fasting, historically speaking
The web site, Intensive Dietary Management claims that fasting is no new fad—it’s been around for centuries. Hippocrates, the father of modern medicine, suggested its use for health purposes as far back as around 400 to 300 BC. He believed that if you were ill, by fasting, you starved the illness. Plato and Aristotle were likewise huge fans of fasting. And almost all of the major religions promote the practice of fasting and have done for centuries.
Three common types of fasts
You can define fasting in multiple ways. Livestrong describes several different types of fasts, including the three that you’ll likely hear about the most: the water only, juice only, and cleansing fasts.
With a water-only fast, you abstain from consuming all foods and drink only water—about two quarts per day. In a juice fast, you are supposed to drink only liquids juiced from vegetables or fruits. A cleansing fast can vary in its regimen, but one popular version involves drinking a beverage made of lemon juice, water, cayenne pepper (or some other spice), and a simple sugar. You drink this six to 12 times a day. You may choose to also drink a laxative tea in the morning and evening for a more intense cleansing fast.
Depending on the type of fast and your health goals, you may fast from one to 14 days, with medical supervision highly recommended for fasts of a longer duration and for water-only diets.
Fasting and your health
In GQ, writer Ben Marcus describes his experience with a medically supervised water-only fast that lasted six days. While at the fasting facility, he discovers how the food industry tricks you into eating salt, sugar, fat, and chemicals in processed foods that are bad for your health. He also learns how excessive intake of foods are associated with a plethora of health issues, from diabetes, to heart problems, high blood pressure, asthma, arthritis, and auto-immune issues. He emerges after six days of fasting 17 pounds lighter, free of arthritis pain, clear-eyed, and significantly lowered blood pressure. He’s also far more aware of what he’s eating.
Huffington Post discusses the pros and cons of the juice-only fast. Many of the web sites that promote the juice-only fast claim that you’ll achieve quick weight loss, gain more nutrition from the juices, and rid your body of toxins. The weight loss claim seems reasonable, but you could just as easily get the nutrients by eating the entire fruit or vegetable, not just the juice. In fact, you’d get more nutrition and fiber, too. The other claims are simply not backed up by scientific evidence.
The article goes on to explain that a juice-only fast likely won’t harm you if you do it for only two or three days. However, you might experience some health issues, such as a dangerous electrolyte imbalance, if you fast for an extended period of time. In addition, you should not attempt a juice-only fast if you have diabetes or kidney disease or are on chemotherapy. It goes without saying that fasting of any type while pregnant is dangerous and should not be attempted.
Livestrong gives more detail on the lemon water cleansing diet, saying that there’s really no proof that it does much to improve your health. You may lose weight—up to three pounds per week—but that weight will quickly come back if you resume the poor eating and exercising habits that caused the weight gain to begin with. It goes on to say that doing a cleansing fast for longer periods may actually damage your health.
The takeaway on fasting
The jury appears to be out on whether or not fasting is indeed good for your health. While Ben Marcus did appear to experience some pretty convincing health benefits—particularly the significantly lowered blood pressure—that might have been accomplished by simply improving his diet and eating less.
In general, a two- or three-day fast doesn’t seem like it could be harmful, assuming you have no concerning health conditions. Perhaps it may even be a way to kick start some good new dietary habits that can continue long after the fast concludes. Here’s a great salad recipe to try right after a short fast—my Beet and Citrus Salad with a Sweet and Tangy Dressing. It’s got plenty of vitamin C, a little fiber, and good amounts of Potassium and vitamin K.