Classified as a detox diet, juice fasting involves drinking only fruit and vegetable juices for a limited period of time, say 2 to 7 days, to allow the body to cleanse itself of unwanted toxins and aid in weight loss, curing it of certain diseases and jumpstarting the road to weaning one from certain addictions like alcohol, smoking or caffeine. A juice fast is also carried out for religious and spiritual purposes.

Juices that come from vegetables such as celery, cucumber, parsley, kale, beet greens, chard, spinach, dandelion leaf, broccoli, cabbage, carrots, beets and sweet potatoes are commonly used in this detox diet. Those extracted from fruits like dark grapes, apples, lemon and the Acai berry are also used. Juices taken from herbs like the yucca root, basil, ginger, milk thistle and peppermint as well as wheatgrass juice and spirulina are also used in a juice fast. Juices may be prepared ahead of time and stored in the refrigerator where they can keep anywhere from three to five days. However, they must be consumed within twenty minutes from opening since oxidation in the area destroys beneficial enzymes found in the juice.

Juices are not complete nutritional regimens in themselves and as such should not be continued for more than a week. A juice fast is also not recommended for children, pregnant and lactating mothers, those that are malnourished and immuno-compromised as well as those who have undergone surgery. While this is also not generally recommended for those in the advanced stages of cancer, many alternative medicine practitioners would argue that fruit and vegetable juices are much more effective cancer cures than chemotherapy or radiotherapy.

Supporters of juice fasting believe that since liquid is easily digested, it leaves more energy for the body to expel toxins that are the culprits behind the degenerative conditions like cancer and obesity plaguing people today. And since the juices are extracted from fresh fruits and vegetables, they are believed to give the body a host of immense health benefits.

Juice fasting is not without its share of critics, however. The idea of drinking natural juice, according to most health experts, is generally harmless and even beneficial when used as part of a healthy diet regimen. However, most juice fasts are promoted in conjunction with certain products like juicers and extractors and as part of detox getaways in some health spas, and serve more of a marketing purpose than an actual health program. In fact, some doctors even go as far as to suggest that detox diets are a waste of money. You could get the same detoxifying effect even by drinking water alone.

Another criticism against juice fasting is that in most detox programs for weight loss that it is usually used in, enemas, laxatives and colon cleansing equipment is used to rid the body of unwanted toxins causing a host of other side effects such as electrolyte imbalances, possible infection and damage due to improper handling and/or sterilization of the colon cleansing apparatus. Moreover, there is no strong scientific evidence to back the claim that juice fasting is actually beneficial for weight loss and overall health for the long term.