Detox fasting is a process of flushing the body of toxins by eliminating all food for a certain period of time, usually two days to a week. Some detox fasts allow the consumption of fruit juices and clear soups, but true detox fasting allows only water. The theory is that by limiting intake to fluids, the body “flushes out the pipes,” eliminating toxins and build-up from the kidneys, liver, and digestive tract. Fluids are taken every two hours to help prevent hunger and dehydration, but doctors recommend limiting physical activity during this time. While fasting, a person is likely to feel sluggish and easily fatigued, and headaches are common.
Periodic fasting has been practiced around the world for thousands of years, though mostly for spiritual reasons. Modern fasting proponents claim detoxification as the primary benefit, but some do report heightened spiritual awareness during an extended fast. Doctors agree that there is definitely a spiritual component to fasting, but many are skeptical about reported physiological benefits. Advocates say that the hangover-like feeling common during fasts is due to the expulsion of toxins from the body, but critics disagree, and attribute the feeling to ketosis.
Ketosis is the process the body switches on when it is not given adequate fuel and turns to stored fat for energy. As the fat is broken down, it releases any chemical substance that may be stored there. These chemicals are released from the fat, but not necessarily released from the body, and can be absorbed into other systems. The body stores toxins in fat to keep it out of the digestive tract where it can enter the bloodstream, so releasing these chemicals without a guaranteed purge can result in illness. Water-only fasts are notorious for initiating ketosis, but juice fasts and brown rice fasts can keep it at bay by providing carbohydrate energy for the body to burn.
Detox fasting should not be seen as a weight-loss plan. A typical fast may involve the loss of a couple of pounds, but experts say that it is simply water weight that will return as soon as the fast is over and normal eating begins. Fasting for more than a week can be dangerous, and can slow the metabolism to the point where the person will gain weight rapidly once normal food intake is restored.
Children and pregnant women should not attempt detox fasting, because proper nutrition at all times is vital to both groups. People with kidney or liver disease, diabetes, anemia, or other chronic disease should not fast, and patients should not undergo surgical procedures before, during, or after a fast. People who take prescription drugs should not attempt a detox fast without the advice of their prescribing doctor, since a reduced caloric intake can affect the way the body metabolizes medication.