Detox Diets: myths vs. reality

by Martica Heaner, PhD on Jan 24, 2013


What you should know about cleanses and juice fasts.

Catherine Towers forked over $1,000 for a physician-supervised “detox.”

“I felt that I needed a drastic change,” says Towers, a brand-marketing consultant in New York City. “Slow weight loss from trying to eat better is uninspiring, so a detox plan was more appealing.”

The fee included a doctor’s visit, nutrient supplements, and protein and fiber powders. For 4 weeks she ate a “clean” lunch of fish and veggies, and drank juices and protein/fiber smoothies at all other meals. “My skin looked amazing, and I lost 10 pounds,” Towers recalls. She admits that after returning to her poor eating and drinking habits, she gained back more than she had lost and is now 20 pounds overweight.

It seems as if everyone has tried a detox diet these days. Although regimens vary, they generally entail a juice fast lasting days or weeks and often include a “cleanse” with limited food and/or “detoxifying” supplements. Serving up a small allotment of calories can produce dramatic weight loss, which makes detoxing tempting to typical dieters.

But what’s unique about this eating (or rather, noneating) trend is that it’s also attracting people not trying to lose weight—normal-weight and fit people. That’s because these fasts are billed as a way to improve health by removing impurities from the body. Many of the juice regimens, like The Gerson Therapy and the Reboot Your Life program seen in the film Fat, Sick & Nearly Dead, purport to cure chronic health conditions and diseases like cancer. All this gives detox diets more street cred than the typical fad diet.

But are they as scientific as they sound?

“Extreme detox diets are not nutritionally balanced,” says Christine Gerbstadt, MD, MPH, RD, a Maryland-based medical doctor and registered dietitian. Even diets that incorporate a meal or smoothie can have too few calories, especially if you exercise while on them. The risks are considerable.

“When you’re not getting enough protein or calories, you can lose muscle mass and experience dangerously low blood sugar, which can cause you to pass out and create electrolyte imbalances that, in extreme cases, can lead to a heart attack,” says Marjorie Nolan Cohn, MS, RD, CDN, a spokeswoman for the Academy of Nutrition and Dietetics who has a private nutrition-consulting practice in New York City.

Of course, not all detox diets go for the starvation approach. Some take a more sensible route, providing juices or supplemented shakes with adequate calories (around 1,200 per day) and protein. “As long as you’re healthy and only follow [a diet like this] for a few days, you will probably lose a few pounds, [but] it’s doubtful that you are going to cure a disease,” says Cohn.

In other words, it’s true that these exercises in portion control can produce weight loss. But the bigger question is whether a detox diet truly “de-toxes.” These diets are said to be able to cleanse the liver and flush the body of toxins, but do they?

What Is a Toxin?

The Merriam-Webster Dictionary defines a toxin as “a poisonous substance that is a specific product of the metabolic activities of a living organism.” Venomous snakes and the bacteria that cause life-threatening botulism (the same stuff in Botox® that gets injected into furrowed brows) produce bona fide toxins. Of course, detox diets are not clearing out snake venom.

In the context of alternative health treatments, toxin is a vaguer term, usually referring to substances alleged to cause health problems. Toxins might include pollutants, pesticides, chemicals or anything else deemed “unnatural” or unhealthy. Sugar is often considered a toxin, even though forms of sugar (juice and maple syrup) are used to detoxify.

What Is Detoxing?

Removing poisons from the body is a seductive idea, but much like the word natural, the term detox is so overused that it can mean just about anything.

Detoxification is an established medical treatment—for helping drug addicts and alcoholics make it through withdrawal. A medical detox can also reduce a buildup of heavy metals, like iron or mercury, or treat a genetic disease that impairs the absorption of copper. Chelation therapy uses a substance that chemically binds with a specific metal to remove excesses from the body. In each case, the treatment targets a specific toxin to be removed.

“But when it comes to dieting, there is no real scientific basis for detoxing,” says Gerbstadt, author of Doctor’s Detox Diet (Nutronics Publishing 2012), a clean-eating plan in which she tries to salvage and redefine the term. A quick Medline® search of peer-reviewed medical journals shows no studies proving that a diet can “cleanse” or “detoxify” the body.

“Detox diets are created by people with products or books to sell, but this is not a legitimate medical treatment,” says Carla Wolper, EdD, RD, a registered dietitian and assistant professor of eating disorders research at Columbia University in New York City.

One of the big problems is that it’s usually unclear what exactly is being detoxed. In 2009, a group of British scientists collaborated to research the claims behind a number of products that claimed to detox. In their “Detox Dossier,” the chemists, biologists and physicists concluded that the term detox was a myth and that “many claims about how the body works that were made when marketing products were wrong and some were even dangerous.” The report noted that little to no evidence was provided to back up most product detox claims (VoYS 2009).

Selling the Idea of Toxic Bodies

Of course, a lack of scientific evidence does not deter the marketers of diets or the people who try them. And the idea that the body is polluted is not new: Back in the 1990s, products alleged that cellulite (fat just under the skin) was toxin-filled sludge that could be removed by special diets or treatments such as brushing one’s skin. With today’s diets, those selling detox can often make a very compelling case. In a recent television exchange, former sitcom star Suzanne Somers, who sells alternative health books and supplements, interviewed Andrew Weil, MD, a medical doctor who also sells alternative health books and supplements. Weil noted, “There is a tremendous amount of toxicity in the environment . . . in many cases, the effects are unknown. But . . . if we don’t have all the evidence in, let’s err on the side of caution and take precautions.” Somers added, “We are exposed to, they say, 80,000 toxins on a regular basis, 200 toxins while we do our morning ritual . . .” (What are these toxins, who says we have them, and what evidence supports the claims? She did not say.)

Are our bodies really polluted with toxins? “If you are not sick, then you probably do not have dangerous toxins in you,” says Wolper. “Even if you are sick, it may not be because you have toxins.” There is no denying we are exposed to environmental pollutants, chemicals in water and processed foods, hormones from animal foods, and pesticides from plant foods, but it’s not clear in many cases if normal exposures are truly harmful. Furthermore, it’s difficult to know whether the body’s own detox systems—like the liver—are so inadequate that they need help from a special regimen.

People rarely, if ever, test their bodies for toxins. Marc Cohen, PhD, professor of complementary medicine at the RMIT University in Victoria, Australia, noted in a 2007 commentary on detoxing that certain toxins can be measured in blood, urine, hair, sweat, fat, saliva, breast milk and semen, yet these tests are rarely done in clinical settings, and even if they are, it’s often difficult to interpret the test results, especially for “subtoxic” doses of multiple compounds (Cohen 2007).

Typical detox dieters do not ask for proof, though. They assume their bodies are polluted and also assume the regimen they follow actually removes toxins. Books, products or practitioners offering a detox diet are vague. Rarely do they specify which toxins their plan is removing, nor do they recommend that you get proof of having a certain level of toxic contamination before you do something about it.

Are you clearing your body of lead, bisphenol A (BPA) or polychlorinated bipenyls (PCBs)? Could it be particulates from the air, artificial sweeteners, your allergy meds or alcohol from yesterday’s margarita? If it’s all of them, how do you know?

Furthermore, no proof of detoxing is provided, despite dramatic promises that it will happen: One claim made about one of the most famous juice fasts of all, The Master Cleanse, states, “Your body will purge itself of toxins that are lodged in joints, soft tissue, cartilage and mucous membranes especially.” And this is apparently achieved by drinking juice made from lemons, maple syrup, cayenne pepper and sea salt. The toxins being removed are not specified, and there’s no evidence they are actually gone.

Detoxing the Liver of Thousands of Toxins . . . ?

The most common claim is that a regimen detoxifies the liver, the body’s own self-detoxification organ. It’s assumed the liver gets clogged like an air conditioning filter and must be cleaned so it can continue detoxifying.

“But there is no evidence showing that a normal liver gets clogged with toxins,” says hepatologist Nancy Reau, MD, an associate professor of medicine at the University of Chicago who treats patients who have liver cancer, cirrhosis and other liver conditions. “The liver is a very sophisticated filter. Everything you inhale, put on your skin or eat enters the bloodstream and is brought to the liver. It then generates specific enzymes to help remove things that are unhealthy or change them to a healthier form.”

Reau concedes she has not read “all” of the medical literature and that being a Western-trained physician can make it easy to misunderstand alternative and homeopathic approaches. Still, she has not seen evidence where peer-reviewed data shows clogging of the liver without a predisposition (a medical condition that would affect processing). “If whatever the liver has to metabolize is present in large amounts (such as alcohol), the liver can’t suddenly become more efficient. However, adding something (like an herb) is not usually going to make it more efficient. You have to give it time to deal with the backlog. So the ingredients in a ‘flush’ are going to have to get in line with everything the liver is already processing.”

Aside from cases of excessive alcohol or drug use, there is no good evidence that the liver needs to be—or can be—detoxed. “The liver is self-cleaning, you just have to give it good fuel in the form of healthy food,” adds Reau.

Effects of a Detox

Of course, people who do detoxes often swear by them: They lose weight and often say they look or feel better. Jocelyn Conn, who works in television in New York City, spent weeks traveling for work, eating fast food and drinking more alcohol than normal. “Afterwards,” she says, “my co-workers and I banded together to cleanse the damage we’d done.” They went on a 3-day juice fast, drinking a different juice every 2 hours. “My skin felt great, I slept really well, and sometimes I felt like I had a lot of energy.”

But were the positive effects due to magical nutrients in the juices, or simply to the fact that she was no longer on the road, was keeping more regular hours and had stopped consuming Cheetos® and martinis? Conn admits that during the fast she sometimes got cranky and felt off-kilter. Detox advocates often brush off negative symptoms as a sign that toxins are being released, yet they offer no evidence that this is the case.

Pros and Cons of Detoxing

The upside of a detox regimen is that cutting out bad eating habits and helping the body eliminate waste more easily make good sense. Choosing organic foods has been shown to reduce pesticide exposure (Smith-Spangler et al. 2012), and eating less processed food and more plant foods means more fiber, more nutrients and fewer chemical additives. Detox diets may even have a valid detox effect if people forgo alcohol that they might otherwise drink. Weil himself asserts that the body can detoxify itself if you simply stop putting toxins into it. He recommends avoiding alcohol, secondhand smoke and household chemicals—as well as drinking more water, eating enough fiber, getting enough exercise to improve elimination and increase breathing (exhalation) rates, and sweating in steam rooms. (Of course, this advice suggests that drinking juice all day or taking certain supplements is not necessary.)

Some people think that a regimented, strict plan helps them mentally prepare to embark on a healthier way of eating. But both Powers and Conn admit that they returned to their former eating vices when their cleanses were over.

And that might be the biggest downside to a detox diet. The belief that it can kick-start a healthier life may only be a fantasy. In fact, the deprivation during fasting may result in a backlash—an impulsive return to junk-food eating. A 2002 study in the European Journal of Clinical Nutrition found that both during but also after a fast, obese people experienced increases in hunger and appetite (Oh, Kim & Choue 2002). In a 2009 study published in the European Journal of Neuroscience, researchers took late-morning brain scans of normal-weight adults as they viewed pictures of high-calorie foods—once after eating breakfast and once after skipping it. The scans showed greater activation in brain areas associated with reward when subjects had skipped breakfast, suggesting a difference between fed and fasted states of mind that might help explain an increased desire for overindulgent eating (Goldstone et al 2009).

But if your routine consists of alternating an occasional detox week to fix a chronic pattern of poor eating habits, what’s the point? “A lifetime of good, healthy eating is going to be more effective than a sometime, short-term cleanse,” says Reau.


Cohen, M. 2007. Detox: Science or sales-pitch? Australian Family Physician, 36 (12), 1009–1010.

Goldstone, A.P., et al. 2009. Fasting biases brain reward systems towards high-calorie foods. European Journal of Neuroscience, 30 (8), 1625–35.

Oh, S-Y., Kim, B.S., & Choue, R. 2002. Appetite sensations and eating behaviors to fasting in obese and non-obese individuals. European Journal of Clinical Nutrition, 56, 86–89.

Smith-Spangler, C., et al. 2012. Are organic foods safer or healthier than conventional alternatives? A systematic review. Annals of Internal Medicine, 157 (5), 348–66.

VoYS (Voice of Young Science). 2009. The Detox Dossier., retrieved Nov. 28, 2012.

IDEA Fitness Journal, Volume 10, Issue 2

© 2013 by IDEA Health & Fitness Inc. All rights reserved. Reproduction without permission is strictly prohibited.

About the Author

Martica Heaner, PhD

Martica Heaner, PhD IDEA Author/Presenter


  • Log In to Comment
  • Shivam Gulati

    Commented Oct 01, 2014
  • Elizabeth Schenk

    Wonderful article! Thank you for posting this!
    Commented May 14, 2014
  • Martica Heaner

    Thanks for all your comments everyone! The case on supplements is not as ironclad as some would have you believe. Even multivitamins, which most people assume as are a good idea, have not conclusively been shown to be that efficacious. The reason is similar to this detox theory...are you lacking something, and if so what? And if so, how do you know? Did you test it and is there even a test for it, and is it a valid test? If you are deficient in a nutrient--and there is a known level of intake that research has shown we must have of that nutrient--then there is a case to supplement. But other than that it's a bit of a guinea pig crapshoot...people stuff themselves with supplements thinking that more is better, when there is usually not proof that more IS better..and in some cases it's worse. I'm generalizing but of course it's a case-by-case (or nutrient-by-nutrient) basis. Even calcium and vitamin D---it's unclear if people really need to supplement, as opposed to simply getting these nutrients from their foods. Supplements usually provide pharmacological doses of nutrients and in ratios in relation to other nutrients that might throw the synergistic effects completely out of whack. It's a very gray area--YES it's a multi billion dollar industry. There is big money pushing the idea that people SHOULD be supplementing with a whole bunch of stuff..but, in fact, the research is lacking to show that we need to. Real food, healthful diet--mostly plant foods...proven recipe for good health...
    Commented Apr 04, 2013
  • Kim Strassmann-Eagle

    Such a fabulous article! I tell this to clients all the time! There is no quick fix! You want a cleanse? Eat clean! More people need to know the lack of evidence regarding cleanses!
    Commented Mar 09, 2013
  • Yvette Ladd

    Yvette Ladd ACE Certified Personal Trainer Certified Spinning Instructor Registered Pharmacist Though not necessarily called 'detox', there are science based programs that are successfully impacting chronic diseases utilizing products and nutritional changes that enhance and support our body's natural detoxification. I, for one, was disappointed that these weren't explored in the context of your article. In today's world it is impossible to avoid toxins and carcinogens despite our best efforts. While I advise 'food first' to my clients, there are times when supplementing is indicated and necessary to make a desired shift in health.
    Commented Feb 23, 2013
  • Jonathan Ross

    Thank you for this well-written, factual article that exposes the detox/cleansing myth. Never been legitimate, never will. Amazing how many fitness pros that should know better are into this. The Placebo Effect would also explain some of the positives that people experience. The need to not feel silly for doing something so obviously without merit means that most people will convince themselves of how great their cleanse was.
    Commented Feb 23, 2013
  • Fernanda Berlowitz

    Great article! Here in Brasil these detox diets are so fashionable right now, I wish I could make all my clients read this. I'll try though, it's very enlightning!
    Commented Feb 15, 2013
  • John Garey

    Thank you IDEA Fitness Journal and Martica Heaner, PhD for a great article on detoxing. Here's how to detox the old fashioned way. Safe and extremely effective. Drink more water. Eat more organic plant foods. Exercise vigorously. Get more fiber by eating more plant foods. Omit or eat fewer animal foods (and choose only free-range, organic, etc., if you do). Don’t smoke. Don’t drink alcoholic beverages. Avoid processed foods.
    Commented Feb 14, 2013

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