To smoothie or not to smoothie? The skinny on blending your fruits and greens

Wednesday, January 18th, 2012

To smoothie or not to smoothie?  It’s the plant-based fitness expert’s blog.  Of course I’m going to tell you to cram as many greens and fruits in as you can, right?  Not so fast.

With an upsurge in ‘smoothies’ and ‘cleanses’ all over the web this time of year, for health, ‘detox’, or weight loss, it’s good to be mindful of why you might not want to make smoothies a part of your daily diet. Especially f you are trying to lose weight, or keep your weight in check, or have blood sugar and triglyceride challenges. Or satiety challenges for that matter.

2 big reasons you might want to limit smoothies

  • decreased satiety as compared to whole foods
  • increased destabilization of blood sugar compared to whole foods

Blending and whirring vegetables and fruits as happens in the making of smoothies disrupts the fiber of the natural food. This disruption impacts the satiety value of that food.  It seems, doesn’t it, that all of the fiber that was there before you blended it should be there in your smoothie.  After all, you didn’t extract the juice from  the apple, the spinach, the blueberries – you just blended it up.  Fiber is fiber, right?

It doesn’t work that way.  Disrupting the fiber, as happens in the process of making a smoothie, exposes more of the surface area of the food.  This means it  is absorbed more quickly, making it more likely that it will effect your blood sugar and insulin levels.  Not only that, but the more of it you want to consume.  When the food is whole, or even chopped, we have more invested in the project of eating by chewing, an important part of the digestive and satiety process.

Calorie consumption comparisons between whole foods, blended foods, and juiced foods with fiber restored

These numbers of analysis should help. Studies comparing caloric intake at a meal following the consumption of either nothing (no preload), an apple, applesauce, apple juice (with fiber added), apple juice (no fiber added) delivered the following results.

Though the apple, applesauce and apple juice with fiber all had the same amount of fiber, there was a clear (and significant difference) in the effect of these 3 forms of apple on satiety and caloric intake.

  • The whole apple decreased calorie intake by 15% in the meal that followed
  • The apple sauce decreased caloric intake by 6% in the meal that followed
  • The apple juice with fiber decreased calorie intake by  1% in the meal that followed.
  • The plain apple juice actually increased total caloric intake by 3%. *

Dramatic differences over time!

What is the take-away from this study?  There is a clear difference between the satiety delivered by whole fruit and foods in contrast to the same foods blended, where the fiber is disrupted.   I know that I can eat a whole lot of fruit if it’s blended.  And the numbers from the testing detailed above explains to me why a smoothie breakfast doesn’t stay with me nearly as long as a my breakfast bowl of steel-cut oats topped with chunks of fruit.

Does this mean you should never have a smoothie, or that they are ‘bad’ for you?  Settle down. On occasion they can provide a quick meal and I like my Vitamix fruit ice cream just as much as the next guy (frozen cherries with banana and carob.  Man!)

But if weight, blood sugar, and insulin levels are a concern to you, then the answer to the question “to smoothie or not to smoothie?” may be clearer.  Occasional?  Sure.  Every day?  Maybe not.

Dr. Caldwell Esselstyn says,

“Avoid smoothies. The fiber is so finely pureed that its helpful properties are destroyed. The sugar is stripped from the fruit, bypasses salivary digestion and results in a surge of glucose and the accompanying fructose contributes to inflammation and hypertension. “

This can probably be mitigated somewhat by limiting the amount of fruit and thinking ‘green drink’ rather than a smoothie packed with several pieces of fruit.

Show me the plants!

First and foremost, I’m interested in getting people to eat more plants.  And if digestion is a problem, or someone for some reason or another is unable to chew well, green smoothies with some fruit may provide a valuable source of nutrition.  It may serve as a way to draw children in to loving their greens (see Smoothie, the Movie).  And athletes may benefit from the large calorie load and fuel replenishment you can get in the form of a blended plant drink.

Thanks so much for coming by and share your thoughts below.  Please ‘like’ and share this post and if you’re on facebook, please join me now on my facebook page here: facebook.

*Resource:  The effect of fruit in different forms on energy intake and satiety at a meal Appetite, Volume 52, Issue 2, April 2009, Pages 416-422 Julie E. Flood-Obbagy, Barbara J. Rolls

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  • Paym says:

    Thanks Lani! This helps reinforce my learning on fibre, calorie density, satiety, etc. The example was excellent, and very easy to remember – those results really say it all!

  • Paym says:

    Oops – meant to ask – how do you make that fruit ice cream – you’ve listed the ingredients, but any particular ratio – and no other liquid – and just put into blender (ok I know you have Vitamix but I use blender)?

    it just got my mouth watering, and I thought, what a great idea to do when ya just “gotta have that sweet”!


    • Lani says:

      Let’s see Paym – I don’t know! I put the frozen cherries in, then add liquid – water does it, can do almond milk for something richer – and whir the VM while tamping it down with the tamper. The idea is to keep it as thick as possible so it’s a sorbet and not soup. Add in carob powder to taste. Can add other fruit, too. A blender might make it harder to get it thick enough and blended at the same time. Yes, it’s a great go-to when you are thinking ‘ice cream’ but without the damage!

  • Dina O'. says:

    Wow! We have a green smoothie in the morning since it is an easy way to get raw greens into my 2-1/2 year old son and it actually keeps us all (myself, hubby and lil man) quite full for hours. Do you have other recommendations for getting small children to eat raw greens. I typically use about a half pound of spinach, flax seeds, frozen blueberries, cherries, mangoes, bananas, and water with a splash of non-alcoholic vanilla. Would be interested in your opinion for other healthier options.
    Thank you!

    • Lani says:

      Hey Dina O.,

      Are there any problems arising as a result of your smoothie plan? Are you trying to lose weight? If the smoothie works for you and no issues, and you can afford the calorie load, then it’s not as problematic. Be sure you aren’t eating all your greens this way though and stay in touch with how your body is responding.

      As far as kids, they can afford the calorie load usually and presents a different scenario as well. It’s easy to go overboard on the fruit in smoothies because they are so yummy and heaven knows it’s not hard to get our ‘fruits’ in – usually!

      You might try making your smoothies a little chunkier so that some chewing is involved, too.

      For the kids – here’s an adorable video I couldn’t help posting a few weeks ago. Regardless of the bottom line on smoothies, it’s a must see for seeing kids enthused about green:

      link to lanimuelrath.com

  • Sibyl says:

    Wow, I will have to rethink my green smoothie habit. My husband and I have one every morning for breakfast. So for tomorrows breakfast I am soaking steel cut oats in almond milk overnight then adding fruit and ground flax. I read somewhere you can do this and enjoy the oats without cooking. I am giving it a try anyway

    • Lani says:

      Sibyl, let me know how the oats come out. I’ve soaked them overnight on many occasions yet still cook it a little in the morning – sometimes with rolled oats you can get away with no cooking.

      I just soak mine in water to not add the fiber-free calorie load of almond milk.

      • Sibyl says:

        It was really good, I added banana and chopped apple, cinnamon and a touch of agave. It was chewy, but quite good. I have soaked rolled oats before, but it was just a bit too creamy for satisfaction. At the time though I was soaking in yoghurt. I no longer eat dairy, so I might like it better with water. I feel the steel cut oats are closer to being whole and I could eat it this way often.

      • Penny says:

        I am new to soaking and the plant based lifestyle. So here’s my question: If I soak rolled oats or steel cut oats (in water or almond milk) do I soak them covered and in the refrigerator? Or covered and on the counter?

        • Lani says:

          Hi Penny,

          I just leave ‘em out on the counter. If theyr’e in the fridge you just have to expend more energy resources to heat them up and they’ll be fine overnight. Congrats on launching your plant-based lifestyle journey! Stay in touch and let me know how else I might assist.

          • Penny says:

            Thank you SO much! I discovered your website last night while looking over http://www.engine2diet.com. I am excited to read your posts!!

          • Lani says:

            Hi Penny, I’m glad you found your way here and how fun to be connected both here and at Engine 2. Thanks for your kind words! Be sure to sign up for my newsletter and to download your Free Fitness Kit as well.

      • We make overnight oats, overnight buckwheat, and sometimes add chia seed, too. You can soak in coconut water, even! There are at least 2 good blogs with recipes for this: Oh She Glows & Peachy Palate. Check out these recipes: link to ohsheglows.com

        Both are healthy blogs, (w/ little or no oil/ refined sugar, etc.)
        When making oatmeal or overnight oats, just watch the portions for mix-ins! …It’s easy to overdo nuts AND dried fruit AND coconut AND granola AND…adding maple syrup, brown sugar, etc. can quickly increase the sugar & calories. But, on the other hand, depending on how active your family is, and any growing kids/ teens involved…would determine how freely you add the extras. (:

  • Carol Hanson says:

    This is great information…..AND, it triggers another question?????
    What’s your take on ‘juicing’? I’ve been hearing that chewing your veggies and fruits is the much better way to consume them. But, if that’s true, what about the people who say that ‘juicing’ is the better way. I’m confused. Can you help clear up the ‘juicing’ question? Thanks!

    • Lani says:

      Carol, in the sample with the smoothies, you see juice listed. Apple juice alone actually raised calorie consumption by 3% in the following meal. In other studies, the same result – the juuice had NO effect on satiety and simply added a calorie load to the meal. So, if weight and blood sugar are a concern (the juice without the fiber impacts blood sugar more dramatically), then this is helpful information.

      There are of course instances where juice may be therapeutic in delivering nutrients where fiber is not tolerated so well – perhaps during illness – but for most of us, sticking to the whole real deal obviously has its advantages.

      • Also depends on ratio of veggies to fruits for both smoothies and juices. Can make a huge difference on the sugar balance! Our green smoothies tend to be much heavier on spinach/ kale, celery, cucumber, parsley, cilantro or mint, etc. and maybe a carrot, 1/2 an apple or pineapple chunks, or just a few grapes to sweeten. Our goal sometimes is to substitute an energizing green smoothie on a hot afternoon rather than default to a vegan frappucino w/ caffeine or a bowl of soy ice cream or something…LOL!!! In these cases, the smoothie is refreshing, cool, & healthier, and really can quell the craving for sweets/ caffeine. Especially on a hot day before or after walk/exercise.

  • Dianne says:

    Lani – thank you for this – I couldn’t agree more – eating a whole food is so much more satisfying physically and mentally then drinking something.

  • Rebekah says:

    Thanks for a very informative article!! I had never heard that blending compromised the fiber content of food – but from experience I know that smoothies don’t keep me feeling full for very long. Like another person commented, I find them such an easy way to get leafy greens & flaxseeds into my kids, and since they are all lean veggie kids, I’m not worried about the calorie load. But I think I’ll start having a smaller glass for myself, as I do have a personal weight loss goal.

    • Lani says:

      Rebekah, I think your thinking is right on about the kids. If there isn’t a weight or health problem, then it may be just the ticket for a busy mom. I find the same thing about smoothies – they can feel fulling at the time, but they don’t carry me as long as my steamy bowl. Thanks for sharing your thoughts.

  • Nancy says:

    I’d be interested in knowing your thoughts about the belief that blending breaks down the cell walls of the fruits and vegetables and thus makes a much greater percentage of the nutrients available to us. For example, Dr. Joel Fuhrman states, “…when we chew a salad, we often don’t do an efficient job of crushing every cell; about 70-90 percent of the cells are not broken open. As a result, most of the valuable nutrients contained within those cells never enter our bloodstream and are lost.” Also, he states that, “An even more efficient way to ensure you receive these needed nutrients is using a blender to puree raw, leafy greens. The blending process aids your body in the work of breaking down and assimilating nutrients. It guarantees that a higher percentage of nutrients will be absorbed into your bloodstream.”

    I don’t like drinking my calories, and fluids don’t keep me full or satisfied, but if the nutritional difference is as significant as Fuhrman says, well…

    Thank you for your time.

    • Lani says:

      Nancy, great question. Which advantage is the greater? Perhaps if medicinal amounts were needed the breakdown might be an advantage, but for the rest of us if eating lots of whole foods we can count on good nutrition. I wonder if it will come up in the debate! At the McDougall Advanced Study weekend in February, both Drs. Fuhrman and McDougall will be there AND they are going to have a debate moderated by John Mackey, CEO of Whole Foods Market. I’ll see if I can float the question sometime during the weekend.

  • natala says:

    love this post! More and more plant-strong docs are coming out against them – including Dr. Esselstyn, Dr. Campbell, McDougall, Sultana, Ledderman, Klapper, Goldhammer, Doug Lisle (Pleasure Trap) and of course our favorite RD Jeff Novick. They are especially not a good idea for anyone who is sick, suffering from heart disease/diabetes/obesity/high bp. It’s sad to me that people are suggesting them when they do not know how harmful they can be for people who are sick – thanks so much for being a voice of reason :)

    • Lani says:

      Hey Natala, thanks for sharing your thoughts. You may know that Jeff Novick is my nutrition consultant – thank goodness he’s such a geek about investigating these things!

  • Lani,
    When I first started making “green smoothies” they were more fruit than greens. But as time passed, they looked like this: spinach, kale, celery, parsley, 1/2 apple, 1 whole orange peeled but with the seeds, flax, water and ice. I was overweight when I started and had NO TROUBLE losing weight drinking the fruit heavy smoothie every morning for over a year. I only changed because my taste buds changed and I preferred a less sweet taste, plus, as my tolerance grew my interest grew in really upping the nutrient content of the smoothies. I can tell you that I never felt better than when I drank those smoothies every day. Oh, and my cholesterol plummeted from 231 to 147 on the sweet version smoothies.

    What can I say? I’m not a doctor or a scientist but also find myself at the center of this controversy as a blogger. Just as there are a now list of Docs against the smoothie, there are lists of professionals who recommend them. In fact, in a recent Doug Lisle lecture he was asked a direct question about green smoothies and he specifically said that people should look for other things to cut out of their diet if they are having trouble losing weight, NOT the green smoothie. So why Natala mentions Doug Lisle as being anti-smoothie is a bit confusing.

    I feel that with the restriction that we choose to place on ourselves eating the no-oil, very little processed food, vegan way, we had better be very careful about spreading fear about drinking green smoothies. They were a staple of my soup, smoothie, salad weight loss effort a few years ago that was a wild success. Now what, I should only eat soups and salads? Really?

    Sorry, but I want to make sure there is some solid evidence backing up these docs claims before I eliminate something that has worked so well for me in the past with real quantifiable results.

    Maybe the advice should be to severely limit the amount and types of fruit in the smoothie, but not the entire green smoothie itself?


  • Lani says:

    Hey Wendy, thanks for sharing your thoughts.

    On the list of dietary compromises, everything is relative. And if one were eating a standard American diet and switched out scrambled eggs and bacon for a green smoothie for breakfast, it’s certainly a change for the better – I think all the docs on the plant-based team would agree with that. Also, if you are having personal success with a green drinks, and you are not concerned about weight or other health measures that might be affecting it, by all means enjoying same may not pose a problem.

    The purpose of the article was to point out the potential problems that fruit and veggie blended smoothies may pose for some – problems of which they may not be aware. It may be slowing down a weight loss or contributing to blood sugar problems. Several responders on facebook and by email wrote to me to share problems they had encountered with weight gain or challenges with lasting satiety and they had never thought of looking to their daily smoothie before. This ended up being potentially quite valuable information for these people.

    Controversy is not a bad thing – it helps us analyze the data, look at our own results, and make decisions about our health. If smoothies are working for you – for example, they can be a great tool for athletes who are very active and need to find quick ways to get in more calories – then use that as feedback for your own choices. But if some of these other problems that blended drinks have been shown to present are part of one’s experience, then this is liberating feedback.

  • Victoria says:

    I love my green smoothies (1/2 banana, 1/2 cup almond milk, flax seeds, spinach , kale and a few blueberries) but I did notice a spike and drop in my blood sugar level so I eat one piece of whole grain toast and I’m set for 4 -6 hours. It’s so much better than the diet coke and bag of mix nuts I use to eat. Happy breakfast.

  • Victoria says:

    Thanks. I raised my kids on a whole foods diet until they hit thier preteens. We got so busy with sports, school, etc… Blah, Blah, Blah. All terrible excuses. But here’s the awesome news. After all three graduated from college they realized they had adopted the western diet and they were not happy with it. I lost my way for a while also. Feeling tired all the time, not sleeping, gaining weight and having a fuzzier brain lead me back to a whole foods, plant based diet. My symptoms were all attributed to menopause. I was misinformed and I knew it. So the research began. This change was also fueled by 2 of my children returning home after college. We love it. We cook together. We meal plan. Share ideas and we try to eat together when our schedules allow. We are all getting along so much better. It’s quite an adjustment with kids returning home and now I know it’s possible to enjoy each other. A ray of hope for others.

    • Lani says:

      What a heart-warming and positive story Victoria. Menopause may be challenging no matter what you do, but there is a way to move through the process that makes a huge difference – how you eat and how you move. I love hearing how you and the kids have madethe food a fun and exciting adventure to share. How pleasing to you, also, as a parent!

  • Sheesh says:

    Awesome post! I shared it on my google + page :)

    I have lost another few pounds after stopping the smoothies and am MUCH more satisfied for breakfast.

    Will have to take a look around your site, great info!

    • Lani says:

      Hi Sheesh,

      So glad to hear things are looking up. Indeed switching out from all the smoothies has made a difference for many. Thanks so much for coming in to share today, I appreciate it!

  • Love this blog! Love your articles. Great info & responses/ feedback. (:

  • Janice N. says:

    Hi Lani,
    The “satiety” links are broken. I’m trying to remember the components: stretch receptors, weight in stomach, …?

    I remember how well researched your post was, but can’t quite remember the content…

    Thanks as always for your help

    • Hi Janice! Good to hear from you! How does it all go?

      I checked the satiety links and in both places I tried they worked for me – so go figure! At any rate, here is the link direct:

      link to lanimuelrath.com

      Let me know if she works, OK? I explore this topic in depth in the book too, I think you’ll likey!

      • Janice N. says:

        Hi Lani,

        I still get:
        “You 404’d it. Gnarly, dude.”

        I see your book’s release date is 2/5/13. Congratulations! That’s so awesome! Can’t wait.

        I’m eating lots of salads lately (yeah!) and sometimes I’m full but still hungry. It’s all very confusing. Thus my quest to read up on satiety.

        Thanks for your help!

        • Ah – full but not hungry – you have to be sure there is enough calorie concentration with the food, not just the bulk which can make you feel like you might be full as in ‘no more room’ but you’re still not satisfied. You’ll love the nutrition chapter in the Fit Quickies book – I go into all of this in great detail because it made such a huge difference for me!

          Off to send you a copy of the article in question, too.

  • […] To smoothie or not to smoothie? The skinny on blending your fruits and greens – Lani Muelrath … […]

  • D'Ann Martin says:

    OK, so my heart is pounding reading the article and link. Then as I scroll down and read the comments, beads of sweat have formed on my brow! I’ve been under the same assumption as Nancy, going by the writings of Joes Fuhrman. When I came across what he wrote, I was instantly relieved, as I detest dark leafy veggies cooked or in salads. I figured I could “have my smoothie and eat it too” since I make them with spinach, kale and other good veggies. But… The weight has been sluggish coming off… Now I’m really confused:( It is better to do without the health benefits of spinach, kale and other dark leafy greans, or do I “smoothie” them and risk not getting to my ideal weight? If I do everything else right, but make my salads with a lighter fair of lettuce, will I be nutritionally sound? Some seriously great chatter btw! Love it!

  • D’Ann,

    Each person must decide what quality of diet they need to be able to meet their health and weight goals. Smoothies with lots of green may work just fine for you, and if they are helping you achieve your goals right now, then work on the other stuff.

    You can also cultivate a taste for things as you move forward. Find a green or two you do think you could take a liking too and start with a small bit in salad, steamed in your steam fry – the fiber full qualities have a lot to offer as well.

    I have no idea how much fruit you are using, or if your satiety through the rest of the day is affected by a smoothie practice.

    Take a look at what else you can keep improving and don’t stress out about it – all in its own good time. You’ll discover what is optimal for you. And make friends with a green or two! My usual and favorite way to eat kale is shredded and cooked into -my hearty lentil-onion-carrot-mushroom soup. Try it! Savory, not ‘greeny’ at all!


  • Jessica says:

    I was just wondering what the outcome of the debate you mentioned was. It sounded interesting. I know it was some time ago, but if there are any articles or info you could share, I’d be interested.

    To put my own two cents in, I’ve been doing smoothies for about a month. I love them. I feel more energetic and clear-headed on them. My workouts have never been better; my energy holds out through the workouts better and I can push harder (doing hybrid of 2 intense beach body workouts).

    I see how satiety may change by processing the fiber, but for folks on a largely whole foods and primarily vegetarian diet, this may not be the biggest concern. For example, I eat many small meals throughout the day so I get plenty opportunity to refuel. And I eat a large mixed salad for lunch every day, plenty of legumes, whole grains, and lots of veggies at dinner. So, I figure I’m covered in the fiber department.

    I agree that if we start adding smoothies and continue to eat a primarily Western diet, smoothies could contribute to weight gain. I see my smoothie habit (cause I think I’m hooked) as a complement to my ever improving whole foods, plant-heavy (although not exclusive) diet.

    • Jessica,

      You are absolutely right that this is a highly individual affair. Some people who struggle with weight do better without a lot of smoothies, some people thrive on them. Pointing out giving it attention and consideration was the point of the article.

      Here is my hand written play-by-play of the Fuhrman-McDougall debate:

      link to lanimuelrath.com

      Thanks for coming by to share your thoughts!


  • Jessica says:

    Thanks so much! I see that no definitive consensus was achieved. Oh well. As you say, they mostly agree.

    I’ve only just found this site today, but I’ve ready 4 very informative articles. Thank you for sharing the info.

    • Jessica,

      Well, nice to meet you! How did we find eachother?

      I’m glad you’ve enjoyed articles so far. Be sure to take advantage of my free gifts – the Plant-Based Blueprint sampler (at top of page) and free chapter from my BRAND new plant-based fitness book which you can download from the link at the bottome of THE BOOK page. Here is a direct link to get the free chapter:

      link to lanimuelrath.com


  • JP says:

    Hi. I have Crohns and ulcerative colitis so I have a breakfast smoothie to gently wake up my digestive system in the morning plus Im afraid that too much fiber will hurt my stomach. My doctor is not helping with the food aspect of my GI issue…so irritating! Anywhoo, do you think a smoothie every day is okay for the reasons I stated? I eat cooked veggies the rest of the day

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  • Diane says:

    Just got back from the doctors this morning. I am on cloud nine because In the summer my bp reading was 165. I drank green smoothies for breakfast and lunch for 6 months and lowered my bp to 130/82… I KNOW now they are good for ME!!!! Happy day today.. I will be glad to give info on doctor etc…..so glad I did this!!!!

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