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Common Questions About Juice Fasting


Updated May 16, 2014

Juice Fasts
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How do people typically feel on a juice fast?

Some people feel hunger pangs, tiredness or headaches, especially in the first few days of the fast. Headaches, tiredness, or difficulty concentrating may be the result of caffeine withdrawal if caffeine intake isn’t gradually reduced prior to starting the cleanse. Following the guidelines to prepare for a detox can help to minimize these symptoms.

Other detox symptoms may include skin eruptions, body odor, bad breath, a coated tongue, constipation, diarrhea, cold sores or canker sores, dry mouth, runny nose or congestion, insomnia, and acne.

Less common side effects of a fast (usually longer fasts) can include fainting, low blood pressure, heart arrhythmias, weight loss, vomiting, and kidney problems. Do not attempt juice fast for longer than three days without consulting your doctor, and if any unusual symptoms occur, discontinue the fast and seek medical attention.

If continued for a prolonged time, fasting can lead to nutrient deficiencies, particularly protein and calcium deficiency.

Who shouldn’t try a juice fast?

People with medical conditions and those taking medications should consult their health care providers before trying a juice fast. Pregnant or nursing women or children shouldn’t try a juice fast.

People shouldn’t go on a juice fast before or after surgery or if they are taking anticoagulant or antiplatelet medication. Juice fasting can reduce the level of blood proteins and alter the way prescription drugs are metabolized in the body. People taking prescription medications should consult their doctors before trying a juice fast, and should never discontinue or reduce their medications on their own.

What if I notice that my stools are red?

Be aware that eating beets or drinking beet juice can result in red stools. It usually causes red discoloration the same or next day. If in doubt, consult your doctor.

How long does a juice fast typically last?

A juice fast typically lasts for one to five days. A juice fast that is longer than three days should be done after consultation with a health care professional.

How can I prevent constipation?

It's important to have regular bowel movements while on a juice fast, because toxins are mobilized from the tissues and they must be eliminated from the body through stools (and urine and sweat) or they may be reabsorbed in the body.

Remedies that can help bowels stay regular on a juice fast include the herbs cascara sagrada or senna, the Ayurvedic herb triphala, or 500 to 1000 mg of magnesium citrate. Some people may opt to try colonic irrigation or an enema.

How long can juice be stored after it is juiced?

If it's stored tightly covered in the fridge, juice can be stored for 12-24 hours after juicing. If you are bringing it to work, pack it in a thermal container or in a container with an ice pack and place it in the fridge if you can.

Can I exercise?

Although cardiovascular exercise boosts the circulation of blood and lymphatic fluid, people who do moderate to strenuous exercise should tone down their exercise regimen during a juice fast. Walking is often recommended. Listen to your body, and stop if you feel lightheaded or weak during a workout.

What should I do if I have to attend a work-related or personal event?

If you have to attend an event, try to stick to vegetables, such as salads and crudités. One or two light meals over the course of a juice fast won't ruin it.

What do people eat after a juice fast?

There should be a gradual return to solid foods. Read the sample guidelines on how to break a fast.

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