Dear Mark: What’s Wrong with Juicing?

Orange JuiceMark,

In your last “Dear Mark” post you said “…why drink your veggies and fruits in concentrated form when you can eat them? I’d just be careful of overdoing the juices.” What is wrong with juicing? I’ve always thought that making fresh juice is extremely healthy for you. Am I right to think that juicing is part of healthy lifestyle or have I been bamboozled by an unnamed, charismatic infomercial personality with bushy eyebrows?

Charismatic personality aside (know what you mean, by the way), I don’t consider juicing a bad thing. However, “eating” only a fraction of a fruit’s/vegetable’s edible content in this case just isn’t going to be as healthy as eating all of it.

Nutrients: Although a generally nutritious option, juice is ultimately a higher sugar, lower nutrient version of its produce sources. Calorie for calorie, for example, you’ll take in more sugar drinking apple juice than you would eating the apple itself. To boot, juicing inevitably reduces or eliminates the majority of fruit and vegetable skin. The skin, for many of our favorite produce pals, berries, apples, pears, plums, figs, etc., contains a hefty amount of a fruit/veggie’s total nutrients. Remember the produce color wheel? Those much-hailed pigments, seats of flavonoids and carotenoids, are concentrated in the skin (and, in some cases, the pulp) as well. Another case of your mother/grandmother being right (again): eat the skin.

Fiber: Again, when you juice you’re deliberately leaving out the skins and pulp (or most of them anyway). Just as the skins and pulp usually hold a lot of the nutrient load, they are the primary (if not sole) source of a fruit’s or vegetable’s fiber content. While I’ve said before that our medical culture overplays the fiber issue (convincing us to down large quantities of grain-based fiber products to “clean us out”), I nonetheless believe that we do require some plant-based fiber for intestinal health. Another crucial benefit of fiber in this case? It slows down the digestion and absorption of the juice’s sugars.

The take-home message is this: juice can offer a decent source of nutrients on days when it’s hard to work in your usual amount of fruits and veggies, but it’s just not an adequate substitute for the real/whole source. (Note: It also requires that you recalibrate your overall carb load that day.)

If you want to include juice in your diet, go for fresh without a doubt. (I wouldn’t suggest buying bottled juices. They’re heated for safety and shelf stability, which reduces their nutrient content and gives them that stale, “off” taste. To boot, the labels may also reveal added sweeteners.) There are plenty of good juicers on the market, and some of us even have access to good juice bars where we live. Personally, I’d recommend making your own. Juice bars generally make their juices fresh for you but might not be as picky in choosing their produce as you would be. Of course, on top of it all you’ll pay a lot more than if you made it yourself. When you juice at home, don’t make a large batch. Juice breaks down pretty quickly. To maximize nutrition (and taste), be sure to make it fresh daily.

As always, thanks for the great questions and comments, everybody. Keep ‘em coming!

Further Reading:

Fun with Fiber: The Real Scoop

On the Problems of Cultivated Fruit

Best Fruit Choices

The Definitive Guide to Primal Eating

What is the Primal Blueprint?

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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46 thoughts on “Dear Mark: What’s Wrong with Juicing?”

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  1. Juicing was a big part of my life for several years. The argument that convinced me was this: you can ingest more goodness when you juice fruits and vegetables than would would ever be able to get from eating because you could not physically eat that much fruit and veg. I was on 2 pints a day. This was before I understood the impact of sugars on insulin etc – I would juice large amounts of fruit (and vegetables) on a daily basis!

    Old habits die hard, so I still make about half a pint of juice from vegetables like beetroot, celery, carrots, spinach and zuchini once or twice a week as a kind of vitamin booster, with the rest of my fruit and veg being consumed in their full form.

    I think I will ditch the juicing altogether soon (how many hunter gatherers had a ‘Champion Juicer’ in their cave!?) but in the meantime am hoping that my current approach is reasonably sound.

  2. Skipping out on the fiber while juicing is sort of cheating your body a little, this is why I am just against it. I think that it also a little expensive to go through all of the fruits and veggies that you would normally not speed through if you were eating the fruits and veggies.

    1. I use the magic bullet so all the fiber stays in the juice. Best of both worlds.

  3. I’m not strongly against juicing. At least its better than a coke or a frappacino. And Methuselah, the beet and celery combo is one of my favorites.

    But I’d have to disagree that it’s cheaper to make your own juice. It takes quite a few whole fruits and vegetables to output just a few full glasses of juice (at least with our office juicer). I’ve actually spent over $20 before just to come up with about 4 cups of juice.

  4. In general I try to go with smoothie over juice. As the whole berry or what not is included with the skin.

  5. My dad used to use a juicer all the time when I was little. He’d always save the leftover pulp and mix it into plain yogurt for me, so the rest of the fruit wouldn’t go to waste. Man, I freakin’ loved carrot juice as a kid, but I never drink juice now.

  6. Excellent post.

    I always try to buy fresh fruit and eat it rather than drink it as a liquid. But I didn’t know the skin contained most of the nutrients! I always heard my parents say it, but I thought it was a myth so I never bothered to eat the skin.

    My favorite fruits are watermelon and pineapple. I can’t eat the skins on those. 🙁

  7. Vitamins or no vitamins I always squeeze my portion of fresh juice in the morning. And I admin I feel really good afterwards. Before my juice mania I drank coffee in the morning and it felt good for a while but not I also got tired and distracted faster.

    Now when I drink only juice and do some exercise in the morning I feel good the whole day.

  8. To the “Is juice good for me?” question, I always answer, “Sure, IF…”

    IF you:
    1. Juice it yourself and use ALL of the entire fruits and/or vegetables. That means buying an industrial strength machine like a Vita-Mix or a BlendTec Total Blender that can handle the load. Don’t bother trying this with your little thirty buck 500 watt blender.

    2. Don’t push yourself over 100 carb grams for the day by blending a bunch of high carb fruits. We’re wanting a fun way to get phytonutrients, not a blood sugar spike!

    Smoothies and juices are fun. But be sure and keep the nutrients and not toss them out with the pulp.

    Be well,
    Ben Fury, CFT, CMT

  9. You might want to consider a Vita-Mix. It makes “whole juice”. Basically, a very powerful blender. Therefore, the juice contains the whole fruit, including seeds in most fruits. I’ve used one for over 10 years and have been happy with the results. You can add protein powder, honey, ice, if desired, making a smoothie. Pricey, but well made.

  10. Living in So Cal, I’m surrounded by “juicies”. Most “juicies” are completely unaware of how much sugar they are consuming. I often wonder if the “benefits” “juicies” claim are as much placebo effect or sugar high as they are due to the phyto-nutrients.

    I often see folks buying 25-50 pounds of carrots at a time, for example, presumable for their beta-carotene-rich juices. I tend to get my preformed Vit A from animal sources, such as liver and grass-fed butter, cod liver oil, etc. Sure takes up less space in the fridge than a huge sack o’ carrots and I don’t have to worry about inefficient conversion or a hernia from carrying sacks of carrots. If everyone consumed that many carrots, there wouldn’t be enough carrots to go around :-).

    While I do make the occasional smoothie at home (with a simple handheld blender stick), I tend to stick to lower sugar produce like berries and stone fruits (as whole as possible, not just fruit juice – or no produce at all), egg yolks/cultured dairy, and ample fats like coconut milk/cream and/or heavy cream. I avoid smoothies from other sources (packaged or smoothie shops) as they are always too high in sugar, usually are mostly ice anyway, have too little or no fat (which I need for energy), and tend to use processed powders for protein. Homemade smoothies are much cheaper, too, and a good use of overripe fruit that the kidlet wouldnt’ touch, anyway.

  11. As with everything in life, balance is the magic word. I firmly believe that juicing can help our bodies to gain easy access to crucial nutrients. I have had my vitamin levels checked before and after a period of juicing regularly. I was amazed by how quickly deficiencies were rectified by juicing.

    Of course I still eat whole fruits and veggies. And I use smoothies to add extra fiber. As one tool in a healthy kitchen, a juicer is in my opinion vital – not to mention fun! Happy juicing, folks!

    Rika Susan

  12. I agree with the concern about too much sugar in freshly made juices. But I recovered from stage four hepatocelluar carcinoma (liver cancer) twelve years ago, in spite of repeated warnings by conventional medical experts that I should be prepared for probable death. There were MANY efforts made to regain my health, one of which was twice daily juicing of leafy greens and other vegetables. Let me be clear about this: I am not claiming that juicing cures cancer. I am saying that, done properly, drinking fresh juices will put much needed phytonutrients into your body so it can do the job of healing more efficiently. I am certain that a fanatical nutritional regime was quite helpful to my recovery (sugar was completely eliminated, by the way). I would recommend smart juicing to anybody, any age, any time.

    Happy Juicing,

    Ann McKeever

      1. Dear Harvey,

        I would be glad to provide you with as much information as I can about my efforts and success at regaining my health after cancer. But, I would rather do it by private email. Please email me at [email protected] and ask me again.

        Be well,

    1. Preach it, Ann. MODERATION, people. I am new to juicing (one month) and did a cleanse with strictly juicing for a weekend. That’s a long time for me and my mind/body got hooked on the “light” feeling in my stomach. I ate other things but really mostly just salad and some protein drinks. And I got TIRED! So I realized what I was doing wrong last week and have added more substance back into my diet. But ain’t no way I want to give up the juicing–I know I’m consuming things I wouldn’t be bothering with at all (beets, celery en masse, broccoli en masse, kale, chard) were it not for juicing.

  13. I love making “juice” in my Vita-Mix! When I can’t sit down and eat a salad, I put a handful of spinach, a leaf of kale, some romaine lettuce and an apple for sweetness. I usually add a little water and a couple of ice cubes and viola, liquid salad!

  14. Got one of those Green Star juicers and use it to make celery/carrot/zucchini/lettuce etc. juices every day. I try to lay off the carrots and beets though as they’re pretty high in sugar and can make me slump afterward.

    Honestly it has made a MASSIVE difference in how I feel. Everyone’s body chemistry is unique though; some people might feel overwhelmed by or just indifferent to the addition of fresh vegetable juices. That’s fine, but I could never give it up now… they’ll have to pry my Green Star from my cold dead hands 😉

  15. I too have read a lot of good things about juicing, as long as you stick to veggies and not fruits. It’s big part of many successful cancer fighting alternative medicine regimens.

  16. Okay all of you are mentioning fruit and carrots. Yeah obviously those have tons of sugar…but i only juice eggplant zucchini yellow squash greens and maybe sometime a lemon…..are you saying that increases the sugar content too? I feel great when i juice and it keeps my skin clear. PLus i eat normal vegetables too. Basically i use juicing as a supplement and as a base to put herbs/ other stuff into/ protein etc. Is that bad in any way?


  17. i’ll have to disagree with you mark, on this one. i think juicing veggies is a great way to get the nutrients of a ton of veggies into your body. i don’t juice fruit – i think that’s dangerous because of the sugar. only veggies. plus when you juice, you can include things that people wouldn’t normally eat, like lemon/lime peel and just the rind of watermelon (not the red part). watermelon rind (the green outer skin, organic, of course) is so nutritious. nobody would ever think of EATING it. plus, it’s difficult for me to digest a lot of cellulose in the veggies when i eat them whole. i see a lot of undigested veggies in my poop the next morning. :-/ i do smoothies (blended salads) everyday too, for some fiber. much easier to digest than eating whole raw veggies. of course, i do enjoy chewing, so i eat some raw/steamed veggies everyday too, even though i don’t digest them well.

  18. I too think that juicing can be very beneficial in some instances. The “Gerson” diet is all about juicing, vegetable diet and coffee enemas. they have cured many people of many different ills with their regimen. I think this approach is very interesting although I am very happy with living primally. Food for thought!

  19. I have to put my two cents in on this old post….

    I do not juice but I do use a vita-mix and throw in veggies with the occasional fruit and ice….this is whole food and it allows me to consume way more veggies a day then just chomping on em….

    Adding sugar to anything kills nutritional profile from the get go.

    Every day I have two whole food drinks; carrots, brussel sprouts, tomatoes, broccoli and sometimes add some blue berries and it has had a huge impact on the amount of veggies I would eat daily.

  20. When I juice, I feel great. I find it is best to do first thing in the morning, on an empty stomach, and to wait another 2-3 hours before consuming solid food.

    I agree that commerically bought juices and smoothies are packed with sugar. Even some of the juices mentioned here are high in sugar (beets, carrots, etc). Here’s my favorite green juice combination:

    Use organic when possible. Keep peel/skin on if organic.

    Romaine Lettuce
    Parsley and/or Cilantro
    Fresh Ginger
    Green Apple, Kiwi and/or a few Green grapes
    Can also throw in some wheat grass–I am gluten intolerant and not sure about it yet for myself

    I use an Omega J8005 juicer, but you can use a Goldstar juicer or Vitamix blender (in which case you retain all the fiber) as well.

  21. I just found this thread so I’m weighing in late. I’m struggling against insulin resistance so I have to be ultra cautious about sugar spikes. When I juice, I use half an organic apple as the base with a variety of other veg but only enough to get about 1/4 to 1/2 cup of liquid. I like the tasty juice, I appreciate the nutrients and ease of getting more variety, but it’s the PULP I love — mixed with eggs and spices, the pulp makes excellent muffins and pancakes with nary a grain in sight. Seriously — pulp, eggs, a bit of nut flour and spices for muffins and thin the same combo with a bit of coconut milk to make pancake batter. Heat up some berries for the top, and load with whipped grain-fed organic cream and you are in Primal heaven!

  22. Hi-
    I started straight juicing 4 days ago. I am hungry all the time and on the first day I lost 3 lbs but since then I have only lost 2 lbs. I pee every 10 minutes and have not had a bowel movement in 3 days. Is that a good thing? I am trying to figure out what is better for me. I want to lose 44lbs (pregnancy weight)

    I have heard that it is good for you, as well as it is bad for you. Can someone please help me out! I am soo confused and just want to eat.

    Thank you!!!!

    1. I’d say you need to do more research before tinkering with your body. Congratulations, you are at the right site. Take Mark’s approach from the top.

      If you are expecting to lose more than six pounds after four days on an easy-fix “diet,” you are setting yourself up for lifelong health problems, and your new child for the orphanage.

  23. What makes you think you have to lose the fiber? In the days that I’d occasionally extract the juice from surplus vegies I always saved the vegie pulp for vegetable stews, or used it as a binding agent in meat loaves. I incorporated it into my whole-grain crackers too (I tolerate 100 g/day of soaked, sprouted, and ground whole grains very well).

    The point of juicing was nutrient availability when rushed and super busy. The times I needed high quality, portable nutrition when my schedule was insane, or I was under huge scheduling or activity stress.

    The fiber I’d freeze and make sure to prepare once or twice a week.

    It was very economical because I got my vegies from other farmers/gardeners in season and rotated my consumption to align with seasonal produce.

    Finally, when I first tried juicing in 1979, I used to say that my beet, celery, and carrot mix would hit me like a shot of whiskey. I quickly figured out it was because of the sugars, concentrated and rapidly ingested. So I was never a routine juicer.

    1. That should have read <100 grams a day of those grains, adjusted downward to accommodate vegetable carbs.

      Also, a couple times back in the '80s I juiced for a few days when I caught a dysenteric bug circulating in the peasant agriculture areas I was working. It let me remove some of the irritation to the lower intestine that high fiber can cause, while still getting phytonutrients.

      But I have always found three to four ounces of juiced vegies to be about the top of my tolerance, max. It is a potent but unquestionably partial food, even where I do build the extracted fiber back in the same or next day. I gave up juicing when I realized I'd feel weird unless I diluted the juice 3:1 or 2:1 with water.

      Remember also that those carrots, beets, etc., have been agronomically selected to have more sugars. "Grok" was most certainly not eating what we today call carrots. Or beets (which started out as chard, then were turned into a sweet root fit…only for cattle feed).

  24. Ok, so I’m like a year late to this blog post. I’ve been a MASSIVE juicer for the last 15 years of my life. Now, I’m dealing with peptic ulcers, chronic gastritis and consequentially, HUGE issues being able to breath properly. My doctor says all the juicing caused me to release way too much stomach acid over a long period of time. I’m on a very bland diet right now until my stomach chills out. Bananas. potatoes, eggs, yogurt. I’m supposed to eat toast and rice but am passing those up right now. My entire digestive system feels so raw, tender and messed up.
    My juicing days are finally over.

    1. Are you still having to eat bland foods? How are things going now?

  25. Why don’t people just have a glass or two of veggie/fruit juice a day as part of their balanced diet. So many straw-man arguments here e.g I drank litres of juice every day for 20 years so juicing is bad.
    I always hated most vegetables (just the way I was raised), but juicing veggies and fruit gives me more nutrients than I have ever and would ever get by purely eating.
    I use a Vita-mix slow-press juicer to get every little bit of nutrients and juice I can. You could always add some of the pulp back into the juice if your worried about fibre.

  26. Juicing is not an “either/or” proposition, and you don’t have to “juice fast” to “detox” to realize the benefits.

    Personally, I use my juicer to increase the variety of my veggie daily consumption.

    “Goin primal” means upping the take of fresh fruits and veggies already. I eat plenty of both.

    What Juicing does, is get me to also intake a lot of the veggies I just don’t care to eat. Things like: Kale, Beets , Celery, Carrots, Chard, Collard Greens, Ginger. And I always make my juice with lemons and limes as well.

    Now don’t get me wrong, I’ll eat those veggies in dishes…just not regularly.

    I regularly eat things like Broccoli, Asparagus, Zucchini, Brussel Sprouts, Onions, Garlic, potatoes, sweet potatoes, bell peppers, cauliflower, tomatoes, cucumber, mushrooms, various lettuce, etc. on a daily basis. These are the veggies I like to cook with and make a wide array of dishes with.

    Juicing the vegetables that I normally don’t eat much of simply and easily boosts my intake of all the good stuff…instead of “forcing myself” to eat veggies I don’t find too palatable in the first place.

    Sugar? Not in my juice. The majority of my dietary sugar is fresh fruit eaten whole.

  27. Using a blender is easy, keeps the fiber, keeps everything. A good blender keeps it all, is easy & quick and dishwasher safe parts. You are right, it’s not brain science here… makes sense.

  28. I’ve heard there are juicers out there that juice up the skin and pulp, so you get almost the whole fruit in the juice, just really ground up. Does this make it juice okay? Or does the fibre have to still be solid when it goes into you for it to do any good?

  29. I’ve been juicing for a few months and feel a tremendous benefit from it. Especially as a way to start my day, I feel it really helps keep me energized and alert without the need for caffeine.

    This does not mean that I stop eating fruits and vegetables. I don’t view it as a replacement, but a supplement.

    Today I drank a juice of kale, parsnips, ginger, graperfruit and apple. I also ate a banana and 2 whole heads of broccoli with steak for lunch.

    You certainly need to eat your fruits and vegetables. But in 3 meals a day, it’s probably impossible to get all the nutrients your body really needs out of fruits and vegetables if you’re only eating them. Maybe juicing doesn’t get you 100% of the way there, but as far as getting lots of extra phytonutrients and antioxidants quickly, it’s a great addition to a healthy lifestyle.

  30. Question about fruit skin –

    1. Fruit juice is bad because it removes the fiber from the skin; skin is good
    2. The skin is dirty because it contains a lot of pesticides and other chemicals; skin is bad

    Is fruit skin good or bad?

    1. Try and eat organic most easily found in smaller local fruit & vegetable shops…

  31. I have read sources that say that to get nutrition out of plants, the cell walls must be broken and that cooking accomplishes this but mastication of raw plants by juicers or your teeth don’t do it. The juice extracted is mostly extra cellular fluids and contains very little mineral or vitamin nutrition. I believe this info was based on studies that tested the nutrient content of various foods cooked, raw, juiced etc. an instinct about this would explain why all people all over the world eat cooked foods and not all raw foods. Except for modern day raw foodists who I think are so disconnected from this that it doesn’t occur to them to look at this fact about how humans prepare food and have done so for millenia and that there might be wisdom in it and a good practice.

  32. If you’re worried about insulin spiking I’d advice against juicing fruit. But juicing leafy greens mixed with other vegetables is incredibly nutritious. That isn’t even debatable, gieco caveman would have devoured it. Juicing gives me a daily detox and source of incredible strength. I don’t need a lab technician or scientist to break the process down.

  33. Fortunately; or unfortunately, I must juice or make smoothies out of many vegetables and fruits due to having Ulcerative Colitis (an IBD). Since my body cannot handle foods like cooked or plain raw kale or spinach, raw fruits, and almost anything with skin or fibrous flesh, the only way I can get the health benefits into my body is by pulverizing them. I just have to be careful to not over-do it.

  34. Juices must be part of our daily food. We should drink juices at day time. The nutrients and vitamins that are present in the juices are really healthy to the body.