Can fasting help purge the body of toxins?

Dear Alice,

Is it really true that fasting can help purge the body of toxins? Is fasting safe? I find all kinds of contradictory information about this on the web.

Thanks for your help.

Just Wondering

Dear Just Wondering,

To some people, it seems logical that fasting, or not eating, helps the body to rid itself of harmful substances, including the toxins you mention. People fast in various ways and for various reasons: fasts can be limited to only juice, water, or herbal tea, for example, and may be done for religious, political, or health reasons, to name just a few. Fasts are often fads, or part of a "health regimen" or a week away "healing" program. Although many people can withstand one day of fasting, as in some religious practices, extended periods may prove unsafe for most others. Fasting is highly unwise for people with eating disorders or impaired immune systems. It is also not recommended for elderly persons, children, or pregnant women. The "health" part of fasting is more myth than fact. In fact, denying yourself nutrients can actually work against you.

To help understand why, a lot can be learned from taking a moment to investigate the body's own detoxification process. The human body is quite ingenious. It was designed to have two major pathways to eliminate harmful substances. First are the immune tissues of the intestinal tract, and second are the enzymes of the liver. Did you know that the intestinal tract generates about 70 percent of our antibodies? These little heroes attach themselves to many of the bacteria, toxins, and viruses that enter our bodies, inactivate them, and prevent many from being absorbed, helping to protect us against infection and illness.

Harmful substances that slip by the intestinal detoxification system are delivered to the liver. This second pathway has two detoxification phases: (1) various transformations occur preventing the perilous substances from creating harm to our bodies; (2) another series of reactions occur, causing these substances to become less toxic. They are then excreted from the body in urine and feces.

So, how does fasting influence the body's detoxification processes? Our nutritional status affects the body's ability to manufacture antibodies and enzymes, and the liver's ability to detoxify. Fasting deprives the body of the raw materials — sufficient calories, proteins, and certain vitamins and minerals — needed to make antibodies and enzymes. Eating keeps our immune system strong.

In addition, specific phytochemicals (naturally occurring plant chemicals in vegetables and fruits) assist in the detoxification pathways, including the following examples:

Indoles, found in broccoli, cauliflower, Brussels sprouts, and other cruciferous (cabbage family) vegetables, are helpful in the liver's first phase.

The liver's second phase is enhanced by isothiocyanates and dithiolthiones, also found in cruciferous vegetables, and by limonoids, found in citrus fruits. These phytochemicals help block carcinogens from damaging our cells' DNA (thereby protecting us against cancer). Compounds in garlic, onions, shallots, leeks, and the spice cumin also enhance phase two of the liver's detoxification system.

So, fasting does not boost the body's disposal system, or cleanse your body in a healthy way. Some people say they feel great during or after a fast. They might feel great because they believe fasting is healthy or has a significant spiritual meaning, or they might feel great because severe calorie restriction (like fasting) can produce feelings of happiness or even euphoria. In either case, fasting isn't actually doing a body good. What's the long-term solution for cleansing your body, then? Eating a sensible diet with plenty of fruits, vegetables, whole grains, lean protein, and unsaturated fats. Throw in a shower or bath every so often, and you'll be clean as a whistle.

Last updated Jun 03, 2015
Originally published Aug 30, 2002

Can’t find information on the site about your health concern or issue?