Nutritionists Agree: This Trendy Diet Plan Is Terrible for Weight Loss

Updated 01/19/17

So you've been eating a little too much junk food, indulging in more rosé than you care to admit, and now you'd like to de-bloat and drop a few pounds. Naturally, you go on a juice cleanse. It's what all the fit kids are doing, so it must be healthy, right?

According to nutritionists, it doesn't matter what the fit kids are doing, because—get ready for it—juice cleanses are absolute bogus. "People think juice cleanses are healthy because they put 'juice' and 'cleanse' together—how could that combo ever be wrong?" says registered dietitian Jenny Champion of Posh Paleo. Dieters tend to believe that juicing for a few days (or weeks) will help you lose weight, reset your metabolism, and get back on track after having fallen off the nutritional wagon. "People fall prey to the idea because they’re desperate to lose weight fast, an all-liquid diet has to shed pounds, and fruit is generally considered one of the healthiest foods on the planet," says Champion.

But nutritionists say this logic is twisted.

"These trendy cleanses do not fulfill a lifetime of happiness and health, but rather a couple days," says Caroline J. Cederquist, MD, creator of bistroMD, a doctor-designed and chef-prepared meal delivery service. "Adding juicing into your diet can be beneficial to receiving vital nutrients; however, juicing should not be the only thing in your diet."

If you're still not convinced that juicing is bad for you, we have more proof. Keep scrolling for five reasons not to go on a juice cleanse.

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Isabella Behravan

1. There's no science behind juice cleanses

No science, no point. "You may hear a lot about the value of juice cleanses, but the fact is that there is no real scientific evidence to back it up," says certified nutrition coach Candice Seti of The Weight Loss Therapist. Juice cleanses may promise to "detox" your body, but we already have a built-in detox system, thanks to our liver, intestines, and kidneys. "Anything you may have heard about juice cleanses—improves digestion, helps you focus, makes you a superhero—is solely anecdotal, and there is no science backing it up," adds Cederquist.

Instead, take this advice: "If you are trying to 'detox' from a period of bad eating or drinking, you can simply detox with good eating and drinking!" says Seti. After all, "Science does back up healthy eating, exercise, and relaxation," says Cederquist.

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2. Your sugar intake will skyrocket

Even green juice is often packed with apples, pineapples, and mangoes, and the fructose in these foods can add up. "Fruit is 'healthy' and 'natural,' but it’s also all sugar," explains registered dietitian Jenny Champion. "Yes, it’s full of vitamins and minerals, which we love, but in terms of calories and metabolism, you could pretty much just down a pack of pixie sticks every day for three days to get the same result."

Consuming so much fruit juice all by itself catapults your blood sugar. "That sky-high blood sugar spike causes insulin, aka the fat storage hormone, to surge," says Champion. "That causes a major crash, which means you'll be craving more sugar by the time you finish cleaning your juicer."

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Pressed

3. Your metabolism will suffer without protein and fat

"Speaking of 'all sugar,' consuming only juice for days is starving your body of protein and fat—both of which are essential for burning fat and keeping your metabolism up," says Champion. Juicing regularly can even have long-term effects on your metabolism, slowing it down to "make losing weight even harder in the future," adds Cederquist.

Beyond causing problems for weight loss, protein and fat deficiency can cause a myriad of other negative effects. According to Seti, "Without protein, we subject ourselves to all sorts of problems including feeling dizzy and weak, a decreased immune system, hair loss, and even increased sugar cravings." (Yes, Seti admits that leafy greens can be a good source of protein, but when you're juicing, it's almost impossible to get enough.) Furthermore, without healthy fats, our bodies aren't able to transport fat-soluble vitamins, which "play major roles in our hormonal system, our bone health, and our nervous system."

Take it from Cederquist: "Juice cleanses when supplemented with protein are much healthier than just pure juice cleanses."

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Crazy Vegan Kitchen

4. A lack of fiber will screw with your digestion

Our nutritionists agree: It's a myth that juicing helps "clean you out." What it actually does is eliminate all the fiber from fruits and vegetables. "This can cause you not to feel full and eventually your body will want to rebel and make unhealthy choices," says Cederquist.

Fiber also helps your colon run smoothly, your heart healthy, and your cholesterol low. "And since our bodies were designed to process solid foods, juicing can actually constipate you," says registered dietitian Lauren O'Connor. "If you are constipated, you are not releasing toxic build-up, so you’ll have to introduce laxatives into the mix."

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Urban Outfitters

5. You'll quickly regain the weight

"You probably will lose a few pounds while cleansing, because you’re starving," Champion admits. But this isn't fat loss—it’s water weight. So the moment you finish your juice cleanse, the pounds will come back. "Also, after however many days you 'cleansed,' you’re going to be ravenous, which means those lost pounds could be back within hours depending on your choice of reward meals," adds Champion. 

If you're looking to "detox" your body or drop a few pounds, don't go on a juice cleanse. Instead, focus on eating a clean, anti-inflammatory diet. Find over 100 amazing plant-based recipes with our favorite cookbook, Clean Green Eats ($20).

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