What the Yuck: How long is safe for a juice fast?
December 24th, 2010
09:43 AM ET

What the Yuck: How long is safe for a juice fast?

Too embarrassed to ask your doctor about sex, body quirks, or the latest celeb health fad? In a regular feature and a new book, "What the Yuck?!," Health magazine medical editor Dr. Roshini Raj tackles your most personal and provocative questions. Send 'em to Dr. Raj at whattheyuck@health.com.

Q: How long is it safe to stay on a juice fast?

Don't do it longer than one day. Our bodies need a varied diet—too much of any one food to the exclusion of everything else deprives us of the essential nutrients we need to function well.

Drink only juice and you'll miss out on protein, healthy fats, and a slew of vitamins and minerals. Plus, healthy adults who swear off foods can suffer fatigue, headaches, constipation, and even heart rhythm irregularities. And certain people should never, ever fast (children, pregnant women, people with diabetes, kidney or liver disease, and anyone taking prescription drugs).

The proponents of juice fasting and other detox diets claim your body needs a "break" from digesting solid food in order to detoxify and help reset some sort of balance. As a GI doctor, I can tell you this is absolutely not true. Our kidneys and liver are responsible for removing toxins, and they do not react well to fasting. So that means your fast could actually prevent your body's natural detox system from doing its job. As for your digestive system needing a rest? False.

But let's be honest: The real reason most people try these extreme fasts is to lose weight fast. While you may knock off a couple of quick pounds on a juice bender, you're just losing water weight so those pounds will come right back. And let me tell you, a few days with less bloat is not worth risking potentially dangerous side effects.

Roshini Raj, M.D., is Health magazine’s medical editor and co-author of “What the Yuck?!.” Board-certified in gastroenterology and internal medicine, Raj is also an assistant professor of medicine at New York University Medical Center and a contributor on the “Today” show.

Copyright Health Magazine 2011

soundoff (90 Responses)
  1. stef

    Well Doc, then if juicing doesn't work then you explain to me why after doing a 7 day cleanse I feel wonderful.......and the fact my GI doctor told me I would be on Nexium forever?......since doing the cleanse I am off the med. Gee I guess if you made money off of suggesting a detox like you do suggesting pills for EVERYTHING, then everyone would be juicing. Cure the problem Doc....stop masking it with pills. Try detoxing yourself might just make you a better doctor.

    January 14, 2013 at 00:14 | Report abuse | Reply
    • surfandbake

      This doctor is an idiot, like most doctors sponsored by the Big Pharma.
      You can juice safely for 30 days.

      September 5, 2016 at 01:05 | Report abuse |
  2. hominid sine nomine

    I agree with stef. Juice fasting for one day is pointless. It takes at least three days for the toxins to start eliminating, and for your body to truly begin to detoxify. Thus, any less then three days is useless. A juice fast should be at least 7 days in my opinion.

    February 16, 2013 at 11:37 | Report abuse | Reply
    • Lojack

      Your kidneys and liver eliminate toxins, you don't need to juice fast.

      August 19, 2014 at 15:43 | Report abuse |
  3. Angie

    Thank you for this report CNN.. now I know that juicing must be good! Since I dont believe ANYTHING that comes from your corrupted voice..
    An awakened soul

    March 28, 2013 at 19:25 | Report abuse | Reply
  4. Chris

    Are you kidding me, with all the evidence of what juice fasting can do to heal a person, you write this kind of crap article? Are you really a doctor? For the most part, doctors get quite a bit of income from the pharmaceutical companies, so it's no wonder they don't want you to be healthy, because then they can't dispense their drugs to you. It's really sad.

    June 8, 2013 at 13:19 | Report abuse | Reply
  5. Tim

    Wow, what a really bad article. You claim to be a doctor, state your opinion and try to pass it off as fact without providing any evidence as to your "facts". You, "doctor" do not know your ass from your elbow.

    July 21, 2013 at 14:33 | Report abuse | Reply
  6. Peter

    Doing a 35 day fast changed my life – for the better. During the fast, I felt better than I have in years.

    December 1, 2013 at 22:00 | Report abuse | Reply
  7. Frances

    Wow, I've heard so many good things about juicing from my students, so I started juicing 11 days ago and I feel so great. I'm 65 years old. I've also started walking 4 miles 4 days a week. I want to juice forever, my cognince, balance & skin has improved so much. Just to mention a few things.

    I don't if this makes a difference but I quit red meat 15 years ago. I still ate chicken & seafood, mostly fish. Has anyone out there juiced for a year or longer.

    August 19, 2014 at 14:27 | Report abuse | Reply
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  9. Jessy

    I want to fast to rest my rectum.. I have serious bleeding everytime I poop everyday. If I fast for 1 – 2 weeks drinking only juices, will I still have to poop ?? Or just urinate ??

    January 15, 2017 at 06:08 | Report abuse | Reply
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