‘Detox diets’: Does science support the claims?

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The promotion of diet plans as a way to detoxify the body is very common. These plans typically involve dietary restrictions and supplementation with various nutrients and herbs.
Even though detox diets are popular in the wellness world, most of these diets are unnecessary, and some can even be harmful to overall health.
In this Special Feature, we explain what detox diets are and see what the science says about whether they offer any health benefits.
How does the body detox?
As part of its constant work to stay healthy, the body continually removes potentially harmful substances through detoxification.
The body’s detoxification system is complex and involves multiple organs, including the liver, kidneys, and skin.
detoxification system
Normal metabolic processes produce toxins endogenously, but the body also acquires them exogenously through exposure to medications and chemicals in food and the environment.
Detoxification involves metabolic processes called biotransformation, during which the alteration of the chemical structure of toxic substances renders them inactive. The body then excretes these substances.
biotransformation
The body’s ability to detoxify depends on various factors, including age, sex, health conditions, genetics, medications, and diet.
For example, because most of the body’s detoxification processes take place in the cells of the liver, liver disease can impair detoxification, which can lead to the buildup of harmful substances such as ammonia.
What are detox diets? 
Even though the body can detoxify through biotransformation, people tout detox diets as a way to promote optimal toxin elimination, improve overall health, and encourage weight loss.
These programs commonly involve juice fasting, supplementation, strict vegan diets, liquid diets, fasting, or other methods that purportedly detoxify the body.
Detox programs can also encourage the use of potentially dangerous practices, such as coffee enemas, in which a person administers coffee through the rectum.
coffee enemas
coffee
Researchers have linked self-administered coffee enemas to severe side effects, such as rectal burns, electrolyte imbalances, and rectal perforation. This practice can even be fatal.
side effects
rectal perforation
Despite numerous claims of improved health by detox diet creators and proponents, most detox programs have no clinical evidence supporting their effectiveness or safety.
Additionally, detox diet programs can be costly, especially those that encourage the use of herbs and other dietary supplements.
A variety of detox diets is available online, including juice and smoothie detoxes and plant-based detoxes.
Many detox diets are not harmful because people usually only follow them for several days, and they typically comprise plant-based foods such as smoothies and juices.
However, detox diets that involve long periods of fasting or extreme calorie restriction, use of herbal supplements, or practices such as enemas can lead to dangerous side effects and potentially have long-term health consequences.
Are detox diets helpful?
Even though most detox diets are unnecessary, this does not mean that the foods a person chooses to consume do not affect the body’s detoxification system.
The body accumulates harmful substances from the environment. These include heavy metals, such as mercury, and persistent organic pollutants (POPs).
persistent organic pollutants (POPs)
POPs are environmental contaminants that are present in foods, soil, and water. They accumulate in body fat, and research has linked them to chronic inflammation, oxidative stress, and an increased risk of mortality.
inflammation
mortality
Even though the body is equipped to detoxify itself, following a nutritious diet and limiting exposure to toxic substances in foods and the environment can help support the organs involved in biotransformation and, by extension, promote health.
However, this does not mean that a person should follow a detox program. Instead, they should support their body’s ability to detoxify by eating a balanced diet.
For example, a diet deficient in protein will negatively affect the body’s ability to detoxify because it needs protein for the enzymatic reactions that are critical to the detoxification process.
enzymatic reactions
critical
Unfortunately, most detox diet plans are lacking in protein, which may reduce the body’s ability to detoxify properly.
Fiber is another important nutrient that can help improve the excretion of toxins through the feces. It can also enhance gut barrier function, which can help protect the organs involved in detoxification from proinflammatory bacteria.
improve the excretion of toxins
Some evidence also suggests that fasting may help promote the health of the liver, which is the major site of detoxification, as well as improving the function of enzymes involved in detoxification.
enzymes
Even though it is clear that a healthy diet is important for the body’s detoxification system, studies on commercial detox diets have not shown promising results.
Research in this area is lacking, with the current body of research limited to poorly designed studies.
A 2015 review noted that a small number of clinical studies investigating the effects of detox diets have found that some programs may enhance liver detoxification and reduce levels of POPs in the body. However, the authors highlight that these studies were flawed and had small sample sizes.
2015 review
In a 2015 study involving 84 women, researchers asked some participants to follow a low calorie lemon detox diet consisting of lemon juice and syrups and other participants to follow a low calorie placebo diet for 7 days. Both groups experienced weight loss and a reduction in insulin levels, suggesting that calorie restriction, not the detox diet itself, improved health.
2015 study
placebo
insulin
Additionally, consumers should be wary of supplements that supposedly detoxify the body. These supplements often contain a blend of nutrients and herbs that may interact with commonly prescribed medications.
A 2019 study involving 22 women found that consuming a detox supplement — containing 1,350 milligrams of a proprietary blend of papaya leaf, cascara sagrada bark, slippery elm bark, peppermint leaf, red raspberry leaf, fenugreek seed, ginger root, and senna leaf — for 4 weeks did not provide any health benefits.
2019 study
papaya
ginger
Even though research shows that certain supplements, such as N-acetyl cysteine (NAC), and specific foods, including cruciferous vegetables, may benefit the body’s natural detoxification system, the simplest way to promote overall health and support the organs involved in detoxification is to follow a nutrient-dense diet rich in protein, fruits, and vegetables.
N-acetyl cysteine (NAC)
cruciferous vegetables
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Detox diet concerns
Even though some detox programs may be harmless, there are safety concerns over detox programs that use extreme methods.
Fasting for long periods, restricting calories heavily, and taking certain dietary supplements can lead to adverse health effects, such as nutrient deficiencies, weakness, mood changes, dehydration, and more.
adverse health effects
mood changes
dehydration
Certain groups of people should avoid detox diets because they are at higher risk of adverse effects. These people include:
individuals with chronic health conditions
anyone who is pregnant or breastfeeding
children and teenagers
people who are underweight
those with eating disorders or a history of these conditions
Before embarking on a detox diet, it is worth discussing plans with a healthcare professional, particularly if the person is taking any prescription medicine.
A balanced diet is important for health and the body’s natural detoxification system, but it is not necessary to follow a special detox diet.
These programs are typically expensive and can lack nutrients that are essential for biotransformation, such as protein.
The bottom line
Even though diets that can supposedly help detoxify the body are popular, the scientific evidence supporting their effectiveness is lacking.
On the other hand, plenty of research supports the notion that following a balanced diet and avoiding drinking, smoking, and exposure to environmental toxins can support overall health, including the body’s detoxification system.
According to currently available research, detox diets are unnecessary and unlikely to benefit health in any significant way. They may even be harmful in some cases.