If you indulged more than usual over the holidays, you may wonder whether a New Year's detox is a good idea. Bold advertisements claim that detox juice concoctions can help you lose weight, cut cravings, boost metabolism and eliminate toxins, all of which sound appealing. But do detoxes really produce these impressive results? Of course not. There's nothing magical about drinking expensive juice made from cucumbers, celery, lemon, parsley or whichever other herbs, vegetables and fruits are tossed in.
The global market for detox products is projected to reach $75 billion by 2026, according to a report from Research and Markets. This includes detox herbs, pills, teas and juice cleanses. So where did the notion of detoxing come from, why is it popular, and is there any harm in giving it a try? (Note: this article focuses on liquid detox diet cleanses only and doesn't cover detoxing from alcohol or drugs, or detox chelation therapy for heavy metal toxicity.)
Detox diets have an interesting historical precedent, said Nitin Ahuja, an assistant professor of clinical medicine in the Division of Gastroenterology and Hepatology at the University of Pennsylvania. There was a long-held fascination with the idea that constipation could lead to poisoning from within the body. This peaked at the turn of the 20th century, when, Ahuja said, "people were doing aggressive bowel regimens or having surgery to remove the colon because they were convinced that retained stool was causing septicemia," or blood poisoning.
Wisely, this practice was abandoned in the 1930s, but Ahuja said that the idea that our guts benefit from cleansing persists today, even though there's no clinical truth to it. "There are good reasons to treat constipation, which can be uncomfortable," Ahuja said. "But in general, the idea that you would need to actively remove by-products of digested food in a normal gastrointestinal system is false."
In the diet world, the term "detoxify" refers to removing toxic substances from the body. There's no denying that we inhale and ingest toxins in our environment, which can come from air pollution, cigarette smoke, household cleaners, alcohol and ultra-processed foods. But we expel most toxins naturally, through sweat, breath, urine and feces, rendering detox products unnecessary.
Health experts agree that the human body's built-in detoxification system, which includes the skin, lungs, liver and digestive tract, is all we need. "Luckily, we don't need to choose supplements or do anything drastic to remove toxins, and instead can rely on organs like the liver and kidneys," said Melissa Majumdar, a Georgia-based dietitian and spokesperson for the Academy of Nutrition and Dietetics. The liver breaks down blood to remove toxins from food, alcohol and medication; the kidneys filter the broken-down toxins and excrete them in urine.
Even though the body is self-detoxing, you can support these efforts by eating a balanced diet and reducing exposure to known toxins. That includes limiting ultra-processed foods and alcohol, drinking more water, eating protein-rich foods, and getting sufficient fiber from vegetables, fruits, nuts and beans.
"I tell my students that a true detox comes with learning to cook a diet that's rich in whole grains, fruits, vegetables, beans and lentils, seafood and oils, accompanied by daily exercise and a good night's sleep," said Thomas Sherman, a professor in the Department of Pharmacology and Physiology at Georgetown University School of Medicine in Washington.
Detox ads often promote the removal of "toxins" but don't specify which ones. Pesticides? Bisphenol A? Phthalates? You can't set up a clinical study to test for "toxin removal" if you don't name the toxin (and injecting toxins into subject's bodies would hardly be ethical), so the idea remains neither proved nor disproved. It's a dream scenario for deceptive marketing.
"The concept of toxins is very vague," Sherman said. "Most detox diets associate toxins with feces, and [claim that] by encouraging bowel movements, you are eliminating these toxins. The idea that toxins stick to the intestinal wall creating toxic sludge and require washing away seems ingrained, and not only is there no evidence this happens, it's simply not the way the system works. So yes, it is all marketing."
I reached out to a dozen companies and practitioners who promote detox diets to ask which toxins are targeted, what proof they have that the toxins are removed, and if they have any clinical studies to back this up. None shared any proof of efficacy.
If there is little-to-no scientific evidence that detox diets work, why is it still a multibillion-dollar industry? It's slick marketing that preys on our human desire for a quick fix, as well as years of ingrained, soul-harming diet culture, which values thinness, appearance and shape above health and well-being.
"Detoxes appeal to our natural desire for a fresh, clean start, and the desire to 'undo' perceived transgressions," said Rachael Hartley, a dietitian and nutrition therapist in Columbia, S.C. "Normal eating means sometimes eating in a less-than-balanced way, and there's nothing you need to do to 'undo' that."
Sherman explains that many Americans eat a lot of ultra-processed foods, which are devoid of fiber, the nutrient required for normal bowel movements. "The sequence of events is predictable," Sherman said. "A poor diet leads to gastrointestinal discomfort and a sense of not feeling quite right, driving a desire to detox and 'reboot the system.'"
The relief that comes with the laxative effect of detox diets may appear to be evidence that toxins were removed. But it's simply the result of a long-overdue poop, a fact that is not nearly as appealing as "detoxification."
While weight loss is possible with low-calorie liquid cleanses, it is also fleeting. "There is no credible science that detox diets do anything more than what all extreme caloric restricted diets also do," Sherman said. "The weight loss results can be dramatic, but involve little actual fat loss; weight regain, therefore, is equally fast."
What about the popular claim that detoxes will help banish cravings? "That one always makes me laugh, because the one consistent thing I've heard from people who have done detoxes is that they're craving solid food the entire time, and often binge after the detox is done," Hartley said.
Some people say that regardless of the lack of clinically proven benefits, they feel energized and rejuvenated after a cleanse. So are detoxes safe to do occasionally?
"There's a potential harm in taking poorly regulated supplements when you don't know what's in the bottle," Ahuja added. "But with food products or juice, there's unlikely to be harm."
It's unclear whether detoxing could affect nutrient absorption or negatively affect the healthy bacteria in the gut microbiome. Ahuja isn't concerned about digestion and absorption if the detox is short-term (most detoxes are one to seven days). And though the microbiome can be affected by long-term diet changes, a short detox is unlikely to have much impact.
"Studies show that if you take colonoscopy prep, and you examine the stool a week later, the microbiome profile matches what was seen prior to the colonoscopy," Ahuja said. "It really doesn't move the needle, since it's a short-term change, so a short-term detox diet likely won't move the needle, either."
Long-term detoxes (more than seven days) however, can lead to nutrient deficiencies, fatigue, electrolyte imbalances, low blood sugar and mood changes.
Majumdar worries that beyond any potential physical harm, detox diets can cause mental or emotional harm. "Having unrealistic expectations about the intent and result can be disappointing," she said. And Hartley said that liquid cleanses play into the restrict-binge cycle that often fuels disordered eating. Detoxing is a fad diet that's part of the diet culture narrative that our bodies are unclean and require fixing.
So if you're considering a cleanse, it makes more sense to establish a balanced eating plan to support your long-term health instead. And ignore the aggressive marketing that makes you feel like your body is filled with toxic sludge, because it's not. The truth is, it's normal to enjoy food. What shouldn't be normal is an industry that exists to make us feel bad about ourselves and make money off false promises. This new year, instead of a detox, try to rid yourself of the influence of deceitful diet ads.