- Fasting, or choosing not to take in food for a set amount of time, is a dietary practice that is used to serve many different functions. Sometimes people fast for religious reasons; other times they may try fasting for weight loss or as a way to address health concerns. The fasting may consist of abstaining from food entirely, or simply obtaining nutrition from fruit or vegetable juice (common in people who fast as a part of a detoxification regime). Here's how fasting works for weight loss and for health improvement.
Fasting for Weight Loss
- Fasting is not recommended by nutrition experts as a tool for weight loss. However, fasting can lead to weight loss because depriving the body of any new calories does force it to tap existing energy sources within the body in order to keep cells running. However, the body will not exclusively use fat stores for this purpose; it can also tap the muscles in order to obtain protein needed for daily life. Thus, fasting can lead to muscle wastage as well as fat loss. In addition, weight loss from fasting tends to be temporary. The weight will come back pretty quickly as soon as the person resumes eating normally again. Fasting on a regular basis can also lead to severe nutrient deficiencies that can adversely affect health.
Fasting for Detoxification
- Some people believe in using controlled fasts as a way to detoxify the body of harmful chemicals and bacteria. This practice is usually not recommended by mainstream physicians, given that there's little evidence to support it, but it is a common recommendation by various types of alternative health care practitioners. Most of the time, the recommended protocol is a juice fast rather than a water fast, meaning the person continues to obtain nutrition from fresh fruit and vegetable juices rather than deprive the body of any nutrition, as with a water fast. The general idea is that many negative health consequences can result from the body having a buildup of toxins in the blood or the wrong types of bacteria in the colon.
- A fast for health reasons may help to kill bacteria in the colon by depriving them of energy sources. Juice is digested and absorbed quickly before reaching the colon. The bacteria are not able to access nutrition in the bloodstream (which comes from the body tapping its energy stores), and thus they begin to die off. Natural healers often believe that having certain types of bacteria in the colon can lead to disease, and killing off the unwanted bacteria (and later replacing them with beneficial bacteria) can prevent or treat diseases.
- Natural health advocates also believe that not taking in solid food for a period of 1 to 5 days can help the body to detoxify existing toxins in the body more efficiently. This is accomplished by not introducing new toxins that tend to overwhelm the body's detoxification resources and also by freeing up energy that would have otherwise been spent by the body conducting digestion. There is no strong evidence to support the idea that this works.