Skip to Content

How long is it safe to juice fast for?

Juice fasting, also known as juice cleansing, has become an increasingly popular way to detoxify the body and promote weight loss. During a juice fast, you consume nothing but fresh vegetable and fruit juices for a set period of time. Some people juice fast for just a few days, while others go on juice fasts lasting a week or longer. But is there such a thing as juicing for too long? Let’s take a look at the safety and health implications of longer term juice fasts.

What is Juice Fasting?

Juice fasting involves eliminating all solid foods from your diet and replacing them with fresh vegetable and fruit juices. On a juice fast, you’ll drink anywhere from six to twelve glasses of juice per day. This provides your body with vitamins, minerals, antioxidants, phytochemicals, and enzymes while eliminating solid food that may be contributing to health conditions or unwanted symptoms.

Typical ingredients used in juice fast recipes include leafy greens like spinach and kale, cruciferous veggies such as broccoli and cabbage, fruits like apples, oranges, berries and pineapple, carrots, beets, celery, cucumber, ginger and herbs like parsley and cilantro. Some people do all fruit juices while others do a combo of mostly veggies with some fruit mixed in.

Potential Benefits of Juice Fasting

There are many touted benefits to cleansing the body through a juice fast. Here are some of the top ways it may improve health:

  • Gives the digestive system a rest
  • Eliminates toxins from the body
  • Encourages weight loss
  • Increases energy and mental clarity
  • Improves skin, hair and nails
  • Lowers blood pressure and cholesterol
  • Regulates blood sugar
  • Boosts the immune system
  • Reduces inflammation

Many integrative health practitioners recommend periodic juice fasting to “reset” the body and give your systems a break from processing solid food. Fasts lasting 3-5 days are common.

Is Juice Fasting Safe Long Term?

While shorter juice fasts are usually considered safe for most healthy adults, prolonged fasts of 7 days or more start to get into questionable territory. Here are some of the potential downsides and dangers associated with long term juice fasting:

Nutritional Deficiencies

One of the biggest concerns with juice fasting for longer than 5-7 days is that it can lead to nutritional deficiencies. Juice contains very little protein, healthy fats or complex carbs. In the long run, this can cause issues like:

  • Loss of lean muscle mass
  • Low energy and fatigue
  • Hair loss or brittle nails
  • Skin problems
  • Weakened immune function
  • Electrolyte imbalances

While juicing floods your body with vitamins and minerals, prolonged deficiency in macronutrients can result in malnourishment.

Blood Sugar Crashes

Since juice contains lots of fruit sugars but no fat or protein, long term juicing can lead to blood sugar highs and lows. Symptoms like dizziness, weakness, headaches, tremors, and heart palpitations can result.

Loss of Healthy Gut Bacteria

Your beneficial gut flora feeds on the insoluble fiber found in whole fruits, vegetables and other plant foods. Without adequate fiber passing through your digestive tract, populations of healthy bacteria can start to decline.

Lack of Fullness and Satiety

Drinking only juices makes it difficult to feel satisfied and full between juices. Appetite usually goes up when you aren’t chewing solid food. This makes prolonged juice fasts challenging for many people.

Potential for Disordered Eating

Juice cleanses shouldn’t be done for quick weight loss, as the results are temporary. However, people with a history of eating disorders may be triggered into unhealthy behaviors. Strict juice fasts could lead to bingeing when resumed normal eating.

How Long is Safe to Juice Fast?

For most healthy people, juice fasts lasting 3-5 days are considered safe when needed. The body can function without solid food for short periods by utilizing stored energy from fat cells. Any longer than this without supplemental nutrition can start to have negative effects.

Here are some general guidelines for the maximum safe duration of juice fasts:

Population Max Recommended Duration
Healthy adults 5-7 days
Obese adults Up to 14 days
Pregnant or breastfeeding women 24-48 hours
Children or teenagers Not recommended
Adults with medical conditions Consult a doctor first

Obese individuals who have excess fat stores can tolerate longer fasts in the 7-14 day range. However, it’s recommended to slowly reintroduce solids after 7 days at the latest. Pregnant or breastfeeding mothers should not juice fast for more than 48 hours due to higher nutritional needs. Juice fasts are generally not recommended for youth or children as their bodies are still developing.

Adults with certain medical conditions like diabetes or eating disorders should avoid prolonged juice fasts altogether or consult a doctor first. Overall, pay attention to how you feel and cut a juice fast short if you experience any concerning symptoms.

Safety Tips for Juice Fasting

If you want to embark on a juice fast longer than a few days, keep these safety recommendations in mind:

  • Include some protein – Add plant-based protein powders or collagen to your juices to prevent muscle loss.
  • Supplement wisely – Take a daily multivitamin or individual supplements to prevent deficiencies.
  • Drink enough – Shoot for six to twelve 16oz glasses of juice per day.
  • Add some fiber – Mix a spoon or two of psyllium husk powder into juices to get 5-10g fiber per day.
  • Monitor yourself – Watch for signs of hypoglycemia like dizziness or fatigue.
  • Break the fast – If you feel unwell, end the juice fast and resume normal healthy eating.

Weaning Off a Juice Fast

Ending your juice fast properly is just as important as starting it. Coming off an extended juice fast should be done gradually over a series of days to avoid refeeding syndrome. This condition results when you shift too quickly from fasting to eating normally.

It’s recommended to slowly transition by adding in bland, easy to digest foods one at a time. Here is a typical schedule for ending a 7 day juice fast:

Day Diet
1-7 Only fresh juices 6-12 times per day
8 Juices + bone broth
9 Juices + cooked oatmeal or cream of wheat
10 Juices + steamed vegetables
11 Juices + raw salad greens
12 Resume normal diet

Listen to your body and ease back into foods slowly if feeling weak or fatigued. Avoid heavy meats, fats, processed foods and sugar during the refeeding period.

Should You Try an Extended Juice Fast?

In the end, whether an extended juice fast is advisable comes down to your health status and goals. While deemed generally safe for some, it may be entirely unsuitable or even dangerous for others. Do your homework before attempting fasting of any kind and consult your physician if you have any concerns.


Juice fasting can be safe for limited periods of 3-7 days for most healthy adults when done properly. This gives the body a chance to eliminate toxins and reset digestive function. However, juice fasts longer than about a week can put you at risk for nutritional deficiencies, blood sugar crashes, loss of healthy gut flora and other complications. Children, pregnant women and people with certain medical conditions should avoid extended juice fasting. If you want to cleanse with juices for longer than 7 days, take precautions to avoid potential dangers.

With sensible preparation and monitoring, you can experience the benefits of juice fasting safely. Pay attention to your body’s signals and transition slowly back to solid foods when your juice cleanse is over.