Fruits and vegetables hold a pivotal role in upholding a balanced and healthy diet. In recent years, juice cleanses have gained traction, promising a concentrated surge of vitamins and minerals, often promoted as a shortcut to weight loss. However, it's crucial to examine the potential benefits and risks associated with this dietary approach.
What is a Juice Cleanse?
A juice cleanse is a short-term detox diet where a person almost exclusively drinks fruit and vegetable juices for as long as 10 days or as short as just a day or two. It involves consuming only juices or homemade concoctions with water, lemon, and added spices. Juice cleanses are often practiced with the hope of weight loss or clearing toxins from the body.
Potential Benefits of Juice Cleanses
While scientific evidence supporting the benefits of juice cleanses remains limited, some potential advantages exist.
Increased Nutrient Intake
Studies have shown that fruit and vegetable juices can boost levels of important vitamins and antioxidants, including folate, vitamin C, vitamin E, and beta carotene. For individuals who struggle to incorporate an adequate amount of fruits and vegetables into their regular diet, juicing can serve as a supplementary method to enhance their nutrient intake. Nutrients in juice include antioxidants, which are crucial for supporting our immune systems and protecting against chronic conditions like cancer and heart disease. Additionally, juices can increase hydration, which improves digestion.
Weight Loss
Juice cleanses may lead to initial weight loss due to calorie restriction. By consuming only juice for a week (and very light meals for two additional weeks), you’ll trim your calorie intake considerably. For this reason, weight loss is likely during a 21-day juice fast. A 2017 study revealed that participants experienced substantial weight losses that lasted after the study ended. The researchers concluded this may be due to changes in the participants’ gut bacteria. However, it’s important to note that the participants only consumed 1,310 calories per day.
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Gut Bacteria Changes
Proponents claim that juice cleanses can alter a person’s gut bacteria. In a 2017 study, a 3-day juice-only diet altered the gut bacteria in 20 healthy adult participants.
Juicing for health
Fruits and vegetables are high in various active compounds that benefit general health and help prevent chronic conditions. For example, they’re a good source of phenolic compounds. These have antioxidant, immune-supporting, and antibacterial properties. Fruit juices may also help lower blood pressure and cholesterol levels.
Juicing for skin health
Some studies suggest that fruit and vegetable juices may promote skin health by reducing inflammation and oxidative stress. However, these are both animal studies. More studies with humans are needed before any conclusions can be drawn.
Risks and Downsides of Juice Cleanses
Despite the potential benefits, it's essential to acknowledge the significant risks associated with juice cleanses.
Lack of Fiber
One of the biggest issues with juicing is the removal of fiber and its nutritional content. Fiber is important for your digestive health, helps regulate blood sugar and cholesterol, and contributes to feelings of fullness. Fiber also fuels good gut bacteria that fight inflammation. Juicing strips away much of the fiber in whole fruits and vegetables, which feeds beneficial bacteria that produce anti-inflammatory compounds such as butyrate. Without fiber, sugar-loving bacteria can multiply. The high sugar content in juice further fuels these harmful bacteria, disrupting the gut and oral microbiome.
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Nutrient Deficiencies
Though fruits and vegetables have lots of important nutrients, they’re notably lacking in protein, fat, and certain micronutrients like vitamin B12, according to Houston Methodist. Going without these nutrients for too long could lead to deficiencies. Juices also lack other nutrients like protein, whole grains, and heart-healthy fats.
Potential Impact on Microbiome
A study from Northwestern University suggests that juicing, which strips the dietary fiber from whole foods, may have a negative impact on your microbiome. Your microbiome is the community of bacteria, fungi, and viruses that naturally live in and on your body. Group one, which had only juice for three days, had significant increases in the type of bacteria linked to inflammation and gut permeability (how well your gut absorbs nutrients and blocks toxins).
High Sugar Content
Without fiber, sugar-loving bacteria can multiply, and juice has a high concentration of sugar per serving. The high sugar content in juice fuels harmful bacteria, disrupting your gut and mouth microbiome. Fruit juice is very high in sugar, which can cause high blood sugar in someone with diabetes or prediabetes, according to Diabetes.co.uk.
Unsustainable Weight Loss
Rapid weight loss isn’t usually lasting weight loss, according to the Mayo Clinic. Though a juice fast might melt away pounds quickly, it’s not a long-term solution - and could lead to a cycle of yo-yo dieting. Severe caloric restriction is not sustainable for most people and rarely leads to long-term weight loss. In most cases, a person will return to their starting weight quickly once caloric restriction ends. Maybe your diet has been worse than usual. Greasy foods, too much alcohol. You just feel like you need a 'detox' and a juice cleanse sounds like the perfect solution. But, science tells us that this is not the way to go.
Low Blood Sugar
Consuming an insufficient number of calories can cause a person to experience symptoms relating to low blood sugar, including fainting, weakness, dehydration, headaches, and hunger.
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Malnutrition
A person on a juice cleanse may not consume enough proteins or fats. Both of these are crucial to physical health, healing, and brain function. Eliminating food groups for extended periods may also lead to malnourishment.
Dehydration
If a juice cleanse includes laxatives or other methods of bowel stimulation, a person could lose too many nutrients in their stool. This can lead to dehydration and imbalanced electrolytes.
Kidney health
Some foods are high in oxalate, a compound that can increase a person’s risk of kidney problems when consumed in high quantities. Foods high in oxalate include spinach and beets. People living with chronic kidney disease may be at risk of oxalate nephropathy. In rare cases, healthy people may also be at risk of this. Oxalate nephropathy is a condition in which the body cannot excrete enough oxalate through urine, causing it to build up in kidney tissue. In rare cases, this can cause kidney failure.
Undesirable Changes from Low Fiber
A study published in 2025 found that juice diets lacking in fiber caused harmful changes to oral and gut bacteria after just three days. Meanwhile, low fiber intake could slow down your digestion, causing constipation.
Social Isolation
The restrictive nature of a 21-day juice fast could mean three weeks of difficulty socializing over meals. During this time, you might lose out on the pleasure of enjoying food with others.
Juicing may increase the risk of eating disorders
For example, an obsessive preoccupation with health-promoting foods and an avoidance of foods considered “less healthy” can lead to orthorexia nervosa.
Other risks
Most people who do juice cleanses don’t eat enough solid food to meet their energy needs. This may lead to increased hunger and energy restrictions that could cause symptoms like: tiredness, headaches, irritability.
Alternatives to Juice Cleanses
For individuals seeking sustainable weight management and overall well-being, several alternatives to juice cleanses offer a more balanced and evidence-based approach.
Balanced Diet
Eating a balanced diet and staying adequately hydrated are the best ways to maintain a healthy weight and support the body’s removal of toxins.
Plant-Based Diets
Based on minimally processed foods, these diets are naturally rich in fruit and vegetables and are associated with reduced body weight. With good planning, a plant-based diet can provide all the nutrients necessary for good health.
Intermittent Fasting
This involves abstaining from eating for limited periods and eating a regular diet at other times. Reviews have linked intermittent fasting with weight loss and improvements in insulin sensitivity.
Smoothies
One delicious way to get the potential benefits of juicing, plus the natural fiber from these foods, is to enjoy fruits and veggies in smoothie form. Beaver recommends trying to blend your favorite fruits and veggies with some Greek yogurt or soy milk for protein. For a green smoothie, pair kale or spinach with a frozen banana.
Recommendations
If you are looking for high-fiber foods, whole fruits and vegetables are among the highest. It’s OK to have juice, but in moderation. If you love juicing, consider blending instead to keep the fiber intact, or pair juices with whole foods to balance the impact on your microbiome. In general, think about making juice with a blender instead of with a juicing machine. If you try juicing, make only as much juice as you can drink at once. Harmful bacteria can grow quickly in freshly made juice.
Consider connecting with a registered dietitian or healthcare professional to help achieve your health and weight-loss goals. Speak with a healthcare professional or registered dietitian if you’re concerned about your diet.