5 Dietitians Weighed In on Juice Cleanses — Here's What They Actually Said

Scroll through TikTok or Instagram for about ten minutes and you'll find at least one influencer halfway through a five-day juice cleanse, glowing like they've discovered the secret to immortality. The promises are bold: flush out toxins, reset your gut, drop weight fast, feel reborn.

But what do actual registered dietitians — the people who spent years studying human nutrition — think about all this? We reached out to five RDs across the country and asked them to be real with us. The answers were illuminating, occasionally surprising, and genuinely useful for anyone trying to figure out where juice fits in a healthy lifestyle.

Spoiler: it's not where most cleanse marketing wants you to think it is.

Myth #1: Your Body Needs a Juice Cleanse to "Detox"

This one might be the most pervasive claim in the cleanse world, and it's the one dietitians push back on hardest.

"Your liver and kidneys are detoxifying your body right now, as you read this," says Atlanta-based RD Janelle Torres, MS, RD, LD. "They don't clock out. They don't need a three-day juice fast to catch up. The concept of 'detoxing' through food or drink isn't grounded in physiology — it's a marketing framework."

The human liver processes and neutralizes waste products, metabolic byproducts, and foreign compounds continuously. Your kidneys filter roughly 200 quarts of blood per day. These are sophisticated, always-on systems. No juice — however cold-pressed and organic — meaningfully accelerates their function in a clinically significant way.

That said, Torres is quick to note that juice isn't without value. "What a well-made vegetable-forward juice can do is reduce your overall inflammatory load by flooding your system with antioxidants and phytonutrients. That's genuinely helpful. But that's not 'detoxing' — that's just good nutrition."

Myth #2: A Juice Cleanse Is a Sustainable Weight Loss Strategy

The scale might tick down during a three-to-five day juice-only period. But Chicago-based dietitian Marcus Webb, RDN, wants you to understand exactly what that number represents.

"Most of what you're losing in the first couple of days is water weight and glycogen stores," he explains. "Your muscles store carbohydrates as glycogen, and glycogen binds to water. When you drastically cut calories and carbs, you burn through glycogen quickly and release that water. It looks like fat loss. It isn't."

Once you return to normal eating, glycogen stores replenish, water comes back, and the number on the scale climbs again. Webb isn't dismissive of people's motivations, though. "I get it — seeing the scale move feels motivating. But if someone uses a cleanse as a kickstart and then crashes back into old habits because the restriction was unsustainable, they haven't actually moved forward."

His recommendation? Instead of a cleanse, try replacing one meal or snack per day with a nutrient-dense juice or smoothie for 30 days. "That's a habit. That's something your body can adapt to and benefit from long-term. A three-day juice fast is an event, not a lifestyle."

Myth #3: Juice Cleanses Heal Your Gut

Gut health is having a major cultural moment, and cleanse marketers have been quick to position their products as gut-healing solutions. The reality, according to San Diego-based RD and gut health specialist Priya Nair, PhD, RD, is more complicated.

"Your gut microbiome — the trillions of bacteria that live in your digestive tract — thrives on diversity and fiber," Nair says. "A juice-only cleanse actually removes most of the fiber from the equation. You're drinking the liquid portion of the produce and leaving behind the insoluble fiber that your gut bacteria rely on as a food source."

She points to research showing that dietary fiber is among the most important factors in microbiome diversity, and that short-term, low-fiber periods can measurably reduce bacterial diversity. "That's the opposite of what most people are trying to achieve when they say they want to 'heal their gut.'"

Nair's practical alternative: add one to two daily servings of whole-fruit smoothies (not strained juice) that retain the fiber, and pair them with fermented foods like kefir, kimchi, or yogurt. "You'll do far more for your gut in a month of that than in five days of juice-only drinking."

Myth #4: Everyone Should Do a Cleanse at Least Once a Year

This idea — that an annual juice cleanse is a healthy ritual, like a spring cleaning for your insides — is deeply embedded in wellness culture. But Seattle-based RD Carla Okonkwo, MS, RD, points out that for certain populations, juice cleanses can actually be harmful.

"Anyone managing blood sugar — whether that's type 2 diabetes, prediabetes, or even reactive hypoglycemia — needs to be really careful with high-volume juice consumption," she says. "Even natural fruit sugars can cause significant blood glucose spikes when you're drinking large quantities without the buffer of fiber, fat, or protein."

Okonkwo also flags concerns for people with kidney disease (high-potassium juices can be problematic), those on blood thinners like warfarin (high vitamin K greens require careful management), and anyone with a history of disordered eating, for whom restrictive eating patterns — even "healthy" ones — can be triggering.

"The 'everyone should do this' framing is the part that bothers me most," she says. "Nutrition is individual. What's fine for one person can be genuinely risky for another."

Myth #5: Daily Juice Is Only Worthwhile as Part of a Cleanse

This might be the myth that does the most damage, because it actually discourages people from incorporating juice into their everyday routine.

"I think the cleanse framing has accidentally convinced people that juice is an extreme measure — something you do for a few days when you've 'been bad,'" says Brooklyn-based RD Simone Ferrara, RD, CDN. "That's backwards. The real value of juice is in consistent, daily use as part of a balanced diet."

Ferrara recommends what she calls a "functional juice" approach: choosing ingredients intentionally based on what your body actually needs, drinking one serving daily as a complement to whole foods, and thinking of it as a nutrient delivery vehicle rather than a meal replacement or a reset button.

"A daily green juice with spinach, celery, cucumber, lemon, and ginger is going to do more for your inflammation levels, your energy, and your micronutrient intake over six months than any five-day cleanse," she says. "Consistency beats intensity every single time in nutrition."

So What Should You Actually Do?

Across all five dietitians, a few themes emerged clearly:

• Daily functional juice beats periodic extreme cleanses for sustainable health benefits
• Retain fiber when possible — smoothies or partially blended juices support gut health better than fully strained options
• Pair juice with whole foods rather than using it as a standalone meal replacement long-term
• Personalize your ingredients based on your health goals — energy, immunity, digestion, and inflammation all have different nutritional levers
• Talk to a healthcare provider before starting any restrictive protocol, especially if you have an existing health condition

At Juice Boosted, this is exactly the philosophy we're built around. We're not here to sell you a five-day reset that leaves you miserable and hungry. We're here to help you find the daily sips that actually make a difference — the ones that fit into your real life, taste good, and give your body what it needs to thrive.

The best cleanse? Honestly, it's the one you never need because you've been nourishing yourself well all along.