Are Juice Fasts Actually Healthy?


When I was in college, I decided that doing a juice fast was the perfect way to get my health back in order. Six hours and two glasses of juice later, I gave up; I was hungry, weak, and supremely grumpy. If this was how I felt after just a few hours, how on earth could I last an entire week?

I may lack the willpower to go on a juice fast, a regimen where you subsist only on fruit and vegetable juices for as many as several weeks, but plenty of other health-conscious people swear by them. And yet, despite claims that juice fasts detox the body, help you lose weight, and even cure serious illnesses, most mainstream medical professionals are speaking out against the practice.

So who should you believe? Let’s take a closer look at the claims, and the science, behind juice fasts.

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Claim: You’ll Lose Weight.

You bet you’ll lose weight, just as you would with any other diet plan that restricts calories. You could, for instance, eat 800 calories worth of chocolate chip cookies, and only chocolate chip cookies, every single day and see the pounds melt off. Juice may have more vitamins and minerals than cookies do, but that doesn’t necessarily mean the weight loss you experience during a fast is any healthier. The weight you’ll loose will most likely be water weight, and you’ll probably gain it all back — and then some, perhaps — as soon as your diet returns to normal.

Claim: Fruits and Vegetables are Healthier in Juice Form.

Juice doesn’t have the same amount of dietary fiber — if it has any at all– as whole fruits and vegetables do. Juice cleanse proponents claim that the lack of fiber gives your digestion system a breather; however, fiber is an essential nutrient for digestion.

Claim: Your Chronic Illnesses Will Disappear.

Juice fasts do provide you with more vitamins and minerals than most of us would get otherwise. These vitamins and minerals do make us healthier, but two things that juice fasting omits, a sustainable number of calories and protein, can actually make us sicker.

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Claim: Your Body Will Detox.

Our bodies are exposed to scant amounts of harmful chemicals every day — there’s no denying that. However, there is no scientific evidence that a diet consisting solely of fruit and vegetable juices will actually deter these toxins. All of the supposed benefits of detoxes are functions that actually performed naturally by our kidneys, livers and intestines — organs that could actually get more damage from a juice fast.

Claim: You’ll Have More Energy.

In an article on juicing for the New York Times, Dr. David Colbert told the author that the euphoria some juice fasters experience is a bodily process called ketosis. “That giddy feeling you get is what diabetics get when your body runs out of sugar and starts using other products for energy… I had a model come in recently, clutching the furniture, explaining to me that she’d been juicing for a week. Your sugar metabolism is completely out of whack.”

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Monika Ka
Monika K.about a year ago

I hate this article. Just encouring people to make healthy choices.

Lois K.
Lois K.2 years ago

"I was hungry, weak, and supremely grumpy. If this was how I felt after just a few hours, how on earth could I last an entire week?"

Maybe that was your body adjusting to the new regimen, and if you had stuck it out, you would have started to feel better. I completely disagree with your claim that 800 calories from cookies would be the same as 800 calories from fruits and veggies. Think about it, and you'll figure out why such a statement is absurd. I do agree that juices lack fiber. That's because the juicer extracts the fiber and skin, which can be very important parts of the fruit or vegetable. I suggest using a blender, instead, at least for some fruits. (Some tough veggies, like carrots, can be hard to puree in a blender.)

BTW, there is a story going around (it might be here on Care2) about a man who weighed over 400 lbs. and went on a juice fast. He not only lost weight, he cured his health problems, took pressure off his spine, legs, and hips, and felt better both mentally and physically. His motivation was that he wanted to live longer to watch his son grow up. He now goes around the country giving lessons on juice fasting, and many communities take part in group fasting to get healthy. If anyone knows the guy's name and has a link, could you post it here?

Syd H.
Syd H.2 years ago

Perhaps the only misnomer the author needs to heed is that it should not be Juice "Fast" but rather Juice "FEAST" instead.

This isn't about drinking a limited amount of 2 glasses of juice. This is about drinking as much as a gallon each day. This is about washing your cells with concentrated nutrients and it's about adding in greens in abundance too.

I happen to personally know people who have done "feasts" of many days including 90, 100, 200 days and more who also bike to work (and back).

Nothing in this article seems to come from anything but hearsay the author wants to believe anyway to support having given up in less than a day.

Watch, "Fat, Sick & Nearly Dead" which is playing for free on YouTube at the moment. Might change your ideas.

And a supposed lack of "protein" in a world where we get way too much and suffer Diseases of Affluence because of it, will not kill us. All religions have fasts as part of their ideology because it gives our digestive system a break. Digestion is energy intensive!

Also, what is "mainstream"? Seems that is the SAD (Standard American Diet) which includes Disease Care (not "Health" Care), a bunch of Pharma which is essentially a form of addiction (especially for Wall Street), and lobbyists to make us believe the Snake Oil claims.

Troy Schreiber
Troy S.2 years ago

I concur with the few sensible-minded people who commented on this article.

The author obviously doesn't understand how juice fasts work or why people do them in the first place.

It's a big mistake to assume that it is a diet or a fad.

When will people on here learn to research the facts behind an article instead of automatically believing someone's opinion as gospel truth?

John S.
Past Member 2 years ago

I guess you have to justify the expensive of a juicer somehow (that is, if you have one).

Freddy Jones
Freddy Jones2 years ago

Quite useful information... Will have me thinking twice about a juice fast..

Galina Medyanova
Galina Medyanova2 years ago

From time to time I drink freshly-squeezed vegetable juice (often mix)- carrot, cabbage,beetroot adding parsley/ celery or simply a tomato smoothie. Rarely freshly-squeezed apple juice for I prefer eating whole fruits.

Bryna Pizzo
Bryna Pizzo2 years ago

Thank you for the education.

Jennifer C.
Past Member 2 years ago


Inga Gorslar
Inga G.2 years ago

This seems a tad biased to me - besides, instead of juice you can always go with the whole fruit and make it a smoothie.