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Can Green Smoothies Make You Feel Worse? Troubleshooting Cleansing Reactions, Weight Loss, Constipation, and More

Robyn Openshaw - Oct 01, 2021 - This Post May Contain Affiliate Links

Green smoothies can be a healthy (and delicious) way to feel better, get healthier, and help you achieve many of your health goals, like losing weight. But for some people, transitioning to a plant-based, whole foods diet isn’t a walk in the park.

What can you do if you aren’t feeling awesome when you start consuming green smoothies? What if you aren't seeing the weight loss results and health benefits you’d hoped for? What about constipation or gas?

In this article:

There’s no need to worry—and most of these reactions are part of a temporary cleanse period as your body adjusts to a new (and improved) diet.

In this post, we’ll troubleshoot some of the most common questions and concerns people have after adopting green smoothies!

Can Green Smoothies Make Me Feel WORSE?

If you’ve recently made the leap to better nutrition with green smoothies and are wondering if it's normal to feel WORSE than you did before, the answer is yes (for a little while anyway, more on that below!).

While some people (most, actually) won’t experience cleansing reactions, some people will. Take them for what they are: a signal that your body is making a big, desperately needed adjustment.

As a rule of thumb, the more dramatic the diet change, the more likely you are to experience some cleansing symptoms. Why? There are two very common reasons:

Your Digestive Tract Is in Poor Shape

If you’re transitioning from the SAD diet (standard American diet) of highly processed, dead foods to a diet rich in fruits and vegetables, your digestive tract is likely in pretty poor repair with limited biodiversity in your gut flora.1

Suddenly add a whole lot of fiber, nutrients, and biodiversity to your gunked-up, leaky digestive tract, and things can get funky and uncomfortable for a little while.

The Toxins You’ve Stored in Your Fat Are Being Released

When you put a dangerous substance into your body (which, if you’ve been eating a lot of processed foods you have been!) your body tucks those toxins into your fat,2 where they can’t damage your organs. This is part of the reason your body is so resistant to parting with those fat stores if you’ve been eating a crummy diet.

However, give your body a lot of good fuel, and you’ll see those fat stores and toxins start to flush — but not without consequences. Part of the reason you may feel bad during an introduction to a healthier diet is that those stored toxins are being flushed from your system.

Understanding What the Fiber in Green Smoothies Does in Your Body

Think of the fiber in green smoothies as a broom: It works by sweeping out the intestines and colon. That’s a good thing! But, as we’ve mentioned, that stuff it’s sweeping out can cause some problems on its way out the door (your colon).

Depending on how much “dust” the fiber broom kicks up, your colon can get backed up and become sluggish.3 Same goes for your kidneys, liver (ever seen anyone whose eyeballs are yellow?), lymph system (bulging, painful nodes in your neck), tonsils, heart and arteries, and even your skin (four letters: Z-I-T-S).

Photo of fiber rich plants from "Why Do I Get Constipated Or Not Lose Weight On Green Smoothies?" at Green Smoothie Girl.
Fiber-rich foods, like the ones you put in green smoothies, help clean out your colon.

The toxic fuel you’ve been eating is 90% of the reason why every single one of these organs gets weak and sluggish. Then, when the miracle happens that you change fuels to a high fiber, nutrient-dense, plant-based diet,4 they get backed up for a while.

How Common Are Green Smoothie Cleansing Reactions, and How Long Will They Last?

First, the good news. Out of the 175 people who participated in my initial green smoothie study (and radically changed their nutrition!) with the green smoothie habit, only 18% experienced very uncomfortable cleansing reactions (also known as Herxheimer reactions). That said, everyone (including myself, more on that next) is bound to experience some mild cleansing reactions whenever diet significantly changes or improves.

These cleansing reactions are most common during the first two weeks of adopting green smoothies into your diet. However, they can also happen two months or six months or even six years later as your body goes through new transformations.

Remember: If you’re like most people, you’ve been eating processed, dead foods for far longer than two weeks. It’s going to take you longer than two weeks to truly “clean house!” Again, the longer you’ve been eating the SAD diet, and the weaker your inherited constitution, the more likely you are to have rough detoxing.

My Personal Experience with Cleansing Reactions

If you’re dealing with intestinal issues, it may give you some comfort to know that the Green Smoothie Girl herself has been in your shoes.

Every day for two months, I drank 4 oz of wheatgrass juice (very potent and medicinal, and 4 oz is a lot, like a pound of wheatgrass). During the second week, I noticed my skin breaking out (a very common detox reaction). A couple of weeks later, I got brain fog and a slight headache. (I never get headaches!) My brain fog was mild and lasted about an hour. (The skin breakout lasted a few days.)

Was it fun? Absolutely not. But it did help me to recognize that these symptoms were my neurological system trying to process a lot of elimination since it had some new power fuel to work with. My point in sharing this personal experience is that everyone has the potential for detox symptoms—even if you’re eating a very healthy diet. We breathe polluted air, we experience stress—both of which have physical byproducts in the body.5

Common Cleansing Reactions From Green Smoothies

If you’re experiencing any of the following cleansing reactions, there’s no need to panic — or heaven forbid, take it as a sign that you should stop incorporating more fiber, bioavailable nutrients, and plant food into your diet!

Stay the course, and know that “this too shall pass!”


If you’ve been eating foods that contain aspartame or monosodium glutamate (it’s everywhere, in potato chips for example!) you’ve been getting a steady dose of neurotoxins. When you switch to a healthier, nutrient-dense diet, your body works to flush these stored chemicals—and headache is a very common symptom. You may also notice a headache as part of withdrawal from sugar or caffeine.6

Inflammation and Skin Breakouts

Similar to headaches, you may notice inflammation flaring up in your joints, muscles, and skin as different toxins make their way out of your body and pass through your system in the blood, tissues, and neurological pathways.

Fatigue or Feeling Cold

As your body works toward a healthier “new normal,” a lot of different processes are going on beneath the surface of your skin. Your system is using its new wealth of nutrients to clear out bacteria, mold, and damaged cells. And your cells are rebalancing their concentration of salt, water, and potassium. This intensive repair work, combined with shifting electrolyte levels can cause temporary muscle fatigue, or feeling cold at different times.

Photo of cold woman from "Why Do I Get Constipated Or Not Lose Weight On Green Smoothies?" at Green Smoothie Girl.
When you radically change your diet, you might end up feeling sick while your body adjusts.

Gastrointestinal Symptoms (Gas, Bloating, Nausea, Cramping)

“Leaky gut syndrome” can develop when a low-fiber, low-nutrient, highly processed diet wreaks havoc on your digestive tract over time and triggers an autoimmune response. This syndrome can actually cause tiny holes to develop in your intestinal tract, as your body struggles to determine friend from foe,7 while digesting your food without the fuel it actually needs.

When you suddenly add a lot of fiber and nutrients to a digestive tract in poor repair, symptoms like gas, bloating, nausea, and cramping can be the temporary price of healing.


Suddenly adding a lot of extra fiber to your diet can temporarily cause some roadblocks (literally) for a digestive tract that isn’t in prime condition. If you’re dealing with constipation, make sure you’re drinking plenty of water. You can also try a coffee enema or a colon massage to help unclog things!

Stalled Weight Loss

Like we talked about earlier, if you’ve been eating a less-than-healthy diet for a while now, your body has been tucking toxins and chemicals into your adipose tissue to protect your organs from damage. It’s no wonder your body is reluctant to release them back into your system! It’s also possible that your hormone levels aren’t in good shape, or that you have food sensitivities.

Keep reading to learn more about how to help your body through this detoxifying process and shed those unwanted pounds (and chemicals!).

1001 Smoothie Recipes from Green Smoothie Girl

Recognizing Possible Food Sensitivities

If a Herxheimer cleansing reaction to green smoothies lasts longer than 2 weeks, you may have a food sensitivity. And if you think “Oh, I’m not one of those people!” think again. Food sensitivities are now epidemic8 because of the numerous ways we degenerate the gut.

Genetically modified grains and spraying Roundup on crops (even on already harvested wheat) have led to an explosion in gluten intolerances. And then a Standard American Diet that includes far too much animal protein and too little plant fiber has created an epidemic of irritable bowel syndrome, Crohn’s disease, leaky gut, fibromyalgia, chronic fatigue, Epstein Barr syndrome, and other fatigue and degenerative gut issues.

What to Do If You Suspect Food Sensitivities

So, what should you do if you suspect food sensitivities?

There’s no need to immediately schedule a panel of expensive blood tests. I’ve personally taken a handful of these tests. And every single time, my “food sensitivities” are totally different.9 My friend Alan Christianson, who has sometimes sent the same blood work from the same patient to two different labs, gets different results 80% of the time—not much better than random chance.

So, again, what SHOULD you do? If you can identify a pattern of which foods are causing you grief, feel free to back off them as you continue to do the work of helping your gut and organs heal, eliminate chemicals and frankenfoods from your diet, and fill your pancreas, thyroid, digestive tract, kidneys, liver, heart, and blood pathways with real foods and nutrients.

Many people are shocked to discover that what they thought was a gluten intolerance was actually an intolerance to Roundup10 — and that once they have significantly improved their diet (and stopped eating genetically modified, sprayed wheat) that intolerance goes away.

Green Smoothies and Weight Loss

I get a few messages along these lines:

Dear GreenSmoothieGirl, I’m drinking green smoothies, and you said they were low-calorie and high in nutrition! Why have I gained two pounds in the last two weeks?

Photo of woman measuring her waist from "Why Do I Get Constipated Or Not Lose Weight On Green Smoothies?" at Green Smoothie Girl.
A great benefit of drinking green smoothies is the weight loss, however, sometimes it doesn't work out that way.

Here’s the short answer: Most people quickly lose weight on green smoothies, and most people’s digestion quickly improves (discussed in depth in The Green Smoothies Diet). This makes sense, since drinking a high volume of low-calorie, high fiber food (only about 200-400 calories per quart) bumps out other foods that are invariably higher in calories, and significantly improves digestion. So, what are a few reasons you might not be seeing weight loss as you’d hoped?

You’re Self-Sabotaging with Treats

Keeping all other things constant, simple physics demands you are increasing your metabolism in many ways—you are burning fat, and you will lose weight. Note that the sentence began, “keeping all other things constant.”

However, if you’re increasing your consumption of junk food because you feel your new green smoothie habit justifies it, that could be one reason why you’re not losing weight. It’s easy to justify extra treats with “Because I’ve been so ‘good’ all day!” but avoid the temptation—especially because, calories aside, that junk will only continue to gunk up your digestive tract!

Your Colon Is Backed Up

If you’re feeling plugged up — and you’re not losing weight to boot — it may be that your body is trying to process so much debris (after a heavily processed diet) that your colon is getting backed up. Before you get out of bed in the morning, deeply massage your transverse colon (preferably with a tennis ball, but your hands will work), starting lower right in your pelvis, straight up to the level of your navel, across a couple of inches inside the left hip bone, and down.

Your Hormone Levels Aren’t in Striking Range

If you’re still not losing weight after a few weeks, you should consider a full blood panel workup at a hormone clinic specializing in bioidentical hormones (rather than synthetic) to determine the health of your endocrine system, especially your thyroid.

If your thyroid isn’t working, with its complex interplay of hormones, you can’t metabolize food effectively and lose weight.11 In fact, I’ve written a whole post on using particular ingredients in green smoothies to support your thyroid and even quiet Hashimoto’s symptoms.

You should know that even if your doctor told you that your TSH (thyroid-stimulating hormone) was in the “normal” range, you may need a broader spectrum blood test. Get both tests for thyroid antibodies. If you’re a woman over 40, ask your practitioner about balancing progesterone, estrogen, and testosterone. Test your vitamin D levels,12 too!

Your Body Is Protecting Your Fat Stores

Like we talked about earlier, your body may be protecting your fat stores — because there’s some bad stuff hidden away in there. Make sure you’re getting plenty of rest and drinking LOTS of water to help give your body a way to actually flush these toxins from your body.

You can also check out my video on permanently lowering your weight setpoint—it’s video number 2 in this masterclass series of 6 videos that you can access for free right now. Learn why your body protects fat, especially if you’re a woman and especially around the middle. And learn what to do about it!

You Need More Time

At the end of the day, you may need to grin and bear the confusing weight plateau for a little while, knowing that your body is doing good, necessary work. You are burning fat, despite what the scale says temporarily, and the discomfort or plateau in weight loss is temporary.

Graphic of fat cells from "Why Do I Get Constipated Or Not Lose Weight On Green Smoothies?" at Green Smoothie Girl.
Fat cells are tricky and hard to get rid of. Give your body time to replace them with muscle.

Keep in mind that water retention (as your fat cells fill up with water to “hold the place” of fat you’re losing in case you want to replenish those stores) can make the numbers on the scale look worse before they look better. So can gaining muscle (which weighs more than fat). Give it time, and pay attention to how you feel — more than what the scale says.

Green Smoothies, Weight Loss, Constipation, and Other “Bad” Reactions

While it’s easy to take unexpected or “negative” reactions to changing your nutrition as a sign that you should stop, stay the course! These cleansing reactions aren’t pleasant, but they are a strong indicator that your body desperately needed this change, and is working hard at cleaning house with a new supply of clean food and fiber.

Thankfully, reactions like constipation, nausea, headaches, skin breakouts, and stalled weight loss generally last two weeks or less. Remember that this, too, shall pass. It is an immutable law that when you replace high-calorie foods with low-calorie, high-nutrition foods (green smoothies!), weight loss and overall health will follow.

Did you experience a cleansing reaction or stalled weight loss when you started drinking green smoothies? What was your experience? Share in the comments section!

Read Next: A Review of John Robbins’ Epic Work, The Food Revolution

Photograph of Robyn Openshaw, founder of Green Smoothie GirlRobyn Openshaw, MSW, is the bestselling author of The Green Smoothies Diet, 12 Steps to Whole Foods, and 2017’s #1 Amazon Bestseller and USA Today Bestseller, Vibe. Learn more about how to make the journey painless, from the nutrient-scarce Standard American Diet, to a whole-foods diet, in her free video masterclass 12 Steps to Whole Foods.

Why Do I Get Constipated Or Not Lose Weight On Green Smoothies?


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  12. Khosravi ZS, Kafeshani M, Tavasoli P, Zadeh AH, Entezari MH. Effect of Vitamin D Supplementation on Weight Loss, Glycemic Indices, and Lipid Profile in Obese and Overweight Women: A Clinical Trial Study. Int J Prev Med. 2018;9:63. Published 2018 Jul 20. doi:10.4103/ijpvm.IJPVM_329_15

Disclosure: This post may contain affiliate links that help support the GSG mission without costing you extra. I recommend only companies and products that I use myself.

Posted in: Detox, Green Smoothies, Health Concerns, Healthy Weight

One thought on “Can Green Smoothies Make You Feel Worse? Troubleshooting Cleansing Reactions, Weight Loss, Constipation, and More”

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  1. MazterGee says:

    Thank you for what you do GSG,,, and the helpful information you have available to us all ,,,, but Why is it always about weight loss, every diet, way of life,,

    I’m here because of issues I have since starting green smoothies,,, the worst issue is acne breakouts and joint pains in my arms (not elbows or hands) and knees and lower back… I do a massive organic green smoothie in the mornings, Kale, Cos Lettuce, 3 stalks of Celery, ¼ cucumber, ¼ zucchini, half an avocado, a slice of pineapple, handful or Frozen blueberries, fresh lemon juice, some water, some fresh parsley when I’ve got it. Joint pain and stiffness and nauses happens within minutes of consuming the smoothie, and I just want to lie down and sleep all day, I’m tired all day until late night.. I sleep ok, wake early.

    I’ve been doing fruit smoothies, and high organic whole foods plant based for many months, the reason for doing green smoothies is to help clear my skin issues,, I’ve eaten cucumber, zucchini, avocado and the fruits daily since forever, it’s adding in the Kale and lettuce, the greens since then I get a lot of nausea, and joint pain and skin breakouts the rest of the day, I have no appetite and don’t eat anything else until the next day when I do a smoothie,, but today I skipped the green smoothie and made a fruit / overnight oats smoothie instead and no joint pain. no bloating whatsoever… ,,

    I know many will say ,"oh it’s detox symptoms".. hmmmm.

    thanks for reading and listening.

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