It is said that vegetable and fruit juices, which are called detox juices, contribute to cleaning the body of harmful substances.
But this statement is not confirmed by relevant studies and, most likely, is clearly exaggerated: the waste of metabolic processes in the human body is bound by liver enzymes and filtered by the kidneys, and is removed naturally - through the intestines, bladder, and sweat glands. 
The benefits and harms of detox juices
It is unlikely that anyone needs to be explained what are the benefits of vegetables, fruits and berries filled with vitamins, macro- and microelements, as well as plant fibers (cellulose) - natural enterosorbents and prebiotics.
So, maybe all these substances, not only useful, but necessary for the body, can be concentrated in the form of freshly squeezed juices and for a few days switch to a cleansing diet using detox juices? Actually, this is what many popular sources recommend, noting the easier absorption of nutrients from juices and advising you to arrange detox days on juices - one, two or three. 
Purchased juices containing sugar and preservatives are not suitable for this: you need to make the most healthy juices - from fresh fruits and vegetables - using a juicer or chopping with a blender.
According to proponents of cleansing juices, they contribute to a healthier diet as a juice detox diet involves avoiding sugar and all refined foods. Undoubtedly, in this, in addition to saturating the body with vitamins, there is also a considerable benefit of detox juices. 
But how these juices support the body's natural detoxification, no one really explains. But it promises a weight loss effect so desirable for most lovers of different diets. To their chagrin, this effect is very short-lived, and after returning to the usual diet, what was lost also returns, often exceeding it.
Experts point directly to the potential harm of detox juices. First, they are devoid of fiber, and, as you know, the role of dietary fiber in the process of digestion and all healthy nutrition is extremely important. Secondly, they drink juices, and the absence of the chewing process does not cause salivation, that is, the digestive and protective functions of the alpha-amylase in saliva (which breaks down starches) and antimicrobial enzymes (lysozyme, lactoperoxidase, lactoferrin) are turned off.
Thirdly, juices from sweet fruits supply the body with so-called fast carbohydrates, which increases blood glucose levels and triggers the release of insulin. And fructose, found in fruit juices, quickly increases triglyceride levels in the blood, which leads to an increase in body fat.
In addition, after juices with a high content of organic acids, heartburn, stomach pain, and intestinal disorders may occur.
Finally, the craze for detox juices from leafy greens (spinach, parsley) and beets containing organic oxalic acid salts - oxalates, can lead to the formation of oxalate stones in the kidneys (kidney stones).
Detox with juices and smoothies
A one-, two- or three-day detox on juices and smoothies (smooth in English - smooth, smooth homogeneous) is considered more acceptable, that is, thick cocktails that contain chopped fiber of vegetables and / or fruits. In addition, flax seeds or bran are added to these cocktails.
Detox green juices are recommended - from cucumber, spinach, zucchini, bell pepper, celery, apple, lettuce with the addition of parsley, lemon, ginger root, young dandelion leaves. 
Since ascorbic acid (vitamin C) begins to oxidize quickly when chopping vegetables and fruits, it is better to consume prepared juices and smoothies immediately, although it is allowed to store in the refrigerator in a sealed glass container (but not longer than four to five hours).
Detox juice recipes - from pumpkin, carrots, beets, various fruits - are presented in the extensive material: Freshly squeezed juices from fruits and vegetables for weight loss .
A few days before the start of cleansing, you need to gradually exclude coffee, sugar, meat, dairy products, bread and wheat flour products from the diet, and also eat more fresh vegetables and fruits.
On cleaning days, only juices and smoothies are used - at least one and a half liters per laziness. And be sure to drink water - room temperature or even warm.
Coming out of juice and smoothies detox involves gradually (over several days) adding foods to your regular diet.
Experts emphasize that detox is not recommended as a long-term weight loss program, especially since such food cannot be considered healthy.
Read also how to avoid the most common nutritional mistakes .