There's nothing wrong with drinking juice, although it's not as healthful as eating fresh fruits and vegetables, which are packed with vitamins, minerals, antioxidants and plenty of fiber, especially in their skins and pulp.
But when a person is downing only fruit and vegetable juice as part of a juice cleanse — usually 16 ounces of juice every few hours, plus unlimited water — and often forgoing food for 3 to 5 days or longer, that's an extreme approach, many nutrition experts say.
And juice cleanses don't involve the typical juice carton found in the supermarket. They require expensive, prepackaged bottles of pulverized produce blends (or they can be homemade in a juicer or blender). The trendy beverages might be a green mixture containing kale, spinach, green apple, cucumber, celery and lettuce or a red concoction made with apple, carrot, beets, lemon and ginger.
Marketers promote juice cleanses as a way to spring-clean a person's insides, ridding them of toxic overload, regaining balance after a period of unhealthful eating, or jump-starting wholesome habits. But not everyone agrees that all-liquid diets and juice cleanses are a way to wellness.
Juice cleanses and liquid detox diets are not a healthful or safe approach to weight loss, said Joy Dubost, a dietitian in Washington, D.C., and a spokeswoman for the Academy of Nutrition and Dietetics. "There's no scientific research that it provides benefits in the short or long term, and it's not an overall healthy approach to eating," she said.
Dubost suggested four misconceptions that people might have about juice cleanses, and other liquid-cleansing regimens.
Myth No. 1: People need to detox in order to be healthy.
The body detoxifies itself naturally, primarily through the action of the liver, kidneys and gastrointestinal (GI) tract, Dubost said. These organs help remove toxins or harmful substances that should not be stored in the body, she said.
Since the body is always in a natural state of cleansing itself, a person does not need to do a juice cleanse or follow a liquid detox diet to be healthy, Dubost said. [9 Healthy Habits You Can Do in 1 Minute (Or Less)]
Myth No. 2: Cleansing is good for your body — it can improve your energy and health.
A juice cleanse offers people a false sense of security that they are doing something beneficial, when in fact people who do these cleanses are doing anything but that, Dubost said. She said the body automatically detoxifies itself, so there's no need to do a juice cleanse to get rid of toxins.
During the first few days of a juice cleanse, a person initially burns their glycogen stores for energy. Using glycogen (the stored form of glucose) pulls a lot of water out of the body, Dubost said, which can show up as weight loss on the scale. A cleanse could also lead to side effects such as a lack of energy, headaches and shakiness due to low blood sugar. Over time, a cleanse may lead to constipation from a lack of fiber, as well as irritability, she added.
Once a person comes off a cleanse, and eats food, that individual could gain all this weight right back, Dubost said. Although she understands that some people may experience a psychological lift from a cleanse, such as perhaps feeling ready or motivated to adopt healthier eating habits, she still doesn't promote the practice, she said.
Myth No. 3: A juice cleanse is a good way to lose weight.
Cleansing is ineffective as a long-term solution to weight loss, Dubost said. A person may shed pounds in the beginning of a cleanse, but this is due to a loss of water, she said.
But the loss of water weight comes at the expense of a loss of muscle, which is a steep price to pay, Dubost said. Weight loss is not always about the numbers on a scale, it's also about the ratio of body fat compared to lean muscle mass, she pointed out.
In other words, the desired outcome of a weight-loss program is to lose more fat than muscle. This might not happen on a restrictive diet like a cleanse because it's low in dietary protein and calories, and while doing one, someone might not have the energy to exercise, which can build muscle. Having more lean muscle and less body fat means burning more calories and boosting metabolism, in the long run.
"There are much healthier alternatives to losing weight and ensuring that the body is working at its best," Dubost added. [Colon Cleansing: 7 Myths Busted]
Myth No. 4: Since celebrities do cleanses, it's something dietitians would recommend.
Celebrities from Beyoncé and Oprah to Gwyneth Paltrow and Salma Hayek have popularized the idea of cleansing. Some stars have tried the approach as a quick way to lose weight, while others have done it to feel healthy after overindulging. Paltrow enthused that a three-week cleanse "worked wonders." "I feel pure and happy and much lighter," reported the slender actress, in Goop, her weekly newsletter, in 2009.
Once people hear the hype and that the "beautiful people" are doing it, everybody else wants to jump on the bandwagon, Dubost said. But it's not a healthful approach, she maintained.
Like other fad diets, cleansing and so-called detox diets promise a quick fix, she said.
"Cleansing may produce short-term results, but it definitely doesn't produce long-term benefits," Dubost said.
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Cari Nierenberg has been writing about health and wellness topics for online news outlets and print publications for more than two decades. Her work has been published by Live Science, The Washington Post, WebMD, Scientific American, among others. She has a Bachelor of Science degree in nutrition from Cornell University and a Master of Science degree in Nutrition and Communication from Boston University.