Juice Fasting: Why?




So you’re feeling a little “toxic” and want to do a “cleanse”. Your friend told you about a juice fast she did. Should you do it?

Juice fasting is a multi-million dollar trend purporting that one can detoxify the body through a nutrition plan that consists of juices made from fruits and vegetables and sometimes herbs with diuretic and laxative properties.

These programs can cost a few hundred dollars, depending on the company you go through and how many days you perform the “cleanse”.



Some juice fasting claims include:

  1. Weight loss
  2. Detoxification
  3. Increased energy and alertness
  4. Mood enhancement
  5. Colon cleansing
  6. Alkalizing the body
  7. Immune system enhancement

Are juice fasts a safe and easy way to lose weight?  

Juice fasting typically lasts 3-7 days, which is about how much time it takes for the body to lose the water weight stored within muscles and subcutaneous fat.

Water is stored within muscle alongside glycogen, which is the body’s storage mechanism for carbohydrates.

As you use up the glycogen stores, your body drops the water weight.

The glycogen is used up over 3-4 days, and all the water weight is dropped over the next 2-3 days. The end result? You lose weight…sometimes up to 10 pounds.  Unfortunately the weight you lose is mostly water weight and probably some muscle, since you’re eating next to no protein.

Once you go back to eating normally again, you will gain much (if not all) of that weight back, since your body will replenish its glycogen (and consequently its water) stores.

Does juice fasting detox the body by removing poisons and toxins?

Detoxification is the process of clearing toxins and excess mucus and congestion from the body. Many of these toxins come from our diet, drugs, and environmental exposure.

Poor digestion, reduced liver function, and poor elimination through the kidneys, bowels, respiratory tract, skin and lymphatic system all add to increased toxicity.

Detoxification involves dietary and lifestyle changes that reduce intake of toxins and improve elimination through the aforementioned organs and pathways. Avoidance of chemicals from refined food, sugar, caffeine, alcohol, tobacco, and drugs helps minimize the toxic load. Drinking extra water and increasing fiber by including more fruits and vegetables in the diet aids in the detoxification process.

While organic vegetable and fruit juices supply some nutrients that are helpful in the detoxification process, the fact is that our bodies are detoxing all the time. If we eat a whole foods diet, exercise, avoid alcohol, get adequate sleep and reduce our exposure to environmental toxins, we will facilitate the detox process in a way that is sustainable and long-lasting, thereby leading to long-term health benefits rather than short-term water loss.

Does juice fasting make you feel more energetic?

Energy comes from carbohydrates, proteins and fats, with carbs being the preferred energy source for the brain. Juice is composed of simple sugars (carbs), which provide immediate (but not sustained) energy. The energy that people report may be due to temporary surges in blood sugar.

Do juice fasts or any other form of detoxing improve digestion and cleanse the colon?


The small intestines and colon are designed to clean themselves. If your bowels become sluggish as a result of your diet, lifestyle, medications, or other factors, then addressing those issues is the way to improve digestion. Ironically, one of the best nutrients to “cleanse” the colon is fiber – which is eliminated in juice cleanses, since all the pulp of the vegetables and fruits is discarded.

Other considerations to improve digestion include increasing hydration, eating pre- and probiotics (or taking a probiotic supplement), identifying food sensitivities and intolerances, and possibly supplementing with magnesium if you are constipated.

What about the alkalizing theory?

Can your food significantly affect your body’s pH?


Your kidneys and lungs are constantly working to maintain a narrow pH range. Your body has mechanisms in place to bring your pH to equilibrium in the event that something happens to raise or lower the pH. This is critical to our survival.  The idea that we should attempt to override this survival system by drinking some vegetable juice is counter to basic physiology.

Can a juice fast boost the immune system?

Fruit and vegetable juices are certainly packed with phytonutrients, vitamins and minerals. These nutrients are helpful in keeping our immune systems strong.

A balanced diet that includes healthy fats and whole foods can also be loaded with these same nutrients, but with added fiber, protein and healthy fats, all of which are also essential for a robust immune system.

On another note, there are some benefits of intermittent, short-term water fasts, but I’ll save that for a future blog.

For more information on anti-inflammatory eating, exercise and naturopathic approaches for optimum health, please don’t hesitate to e-mail me or contact our office for a consultation.




About the Author

Dr. Geoff LecovinNaturopathic Physician/Chiropractor/Acupuncturist/Certified Strength and Conditioning Specialist/Corrective Exercise Specialist/Performance Enhancement Specialist/Certified Sports Nutritionist/View all posts by Dr. Geoff Lecovin