May 27, 2017
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The Truth About Detox Diets

by Ben Cosgrove  |  

If you’ve spent time on the Internet lately, read a lifestyle magazine, or watched a celebrity interview (or “The Dr. Oz Show,” for that matter), chances are you’ve heard or seen something about “detoxing”—that ubiquitous yet amorphous term that refers to various dietary regimens that supposedly clean you out, give your body a radical reboot, and help you drop weight fast. These range from one-day fasts to diets promoted by celebrities like Beyoncé and Gwyneth Paltrow to techniques as dramatic as colon cleanses and coffee enemas.

The idea of cleaning yourself out as a way of kick-starting healthier habits may be appealing, especially if you’ve been eating poorly, drinking too much alcohol, or otherwise treating your body less than optimally. But there’s no good evidence to back the “detox” concept—and furthermore, it makes no scientific sense, as we discuss below. And some of the plans could be dangerous, especially for certain groups of people. Here’s a quick primer on the detox trend and why, as with so many other things in health (and life), it isn’t the quick fix it claims to be.

What does “detox” mean, anyway?

Short for detoxification, the term for decades was used almost exclusively to refer to the process of withdrawal from alcohol or drugs by people addicted to those substances. In some cases, that withdrawal could bring agonizing symptoms like the delirium tremens experienced by alcoholics, or the pain and vomiting associated with kicking heroin or other opiates.

Today, though, "detox" has become a catchall term for any number of non-traditional diets, fasts, or procedures that proponents claim reset your metabolism, remove unwanted pounds, and eliminate so-called "toxins" from the body. Among the best known and most extreme is the Master Cleanse, in which followers consume nothing but warm salt water, laxative tea, and a liquid concoction of lemon juice, maple syrup, and cayenne pepper for 10 days. But there are any number of other plans and books, from Dr. Oz’s 3-Day Detox Cleanse ("All you need is 3 days, a blender and $16 a day!") to the 10-Day Green Smoothie Cleanse to the Martha’s Vineyard Diet Detox, which promises a startling (and almost definitely unsafe) 21-pound weight loss in 21 days. And a quick Google search will lead you to numerous 1-, 3-, and 5-day commercial juice cleanses for sale, some with hefty price tags. A 5-Day Juice Cleanse sold on the Williams Sonoma website, for example, costs $330 before shipping and handling and includes juices with names like “D-Tox” and “The Master.”

What are these toxins that so many plans claim to eliminate?

Toxins are generally defined as substances created by plants, animals, and microorganisms that are poisonous to humans. Some medications can also be toxic when used in large amounts.

Among detox proponents, though, that definition has been hammered so flat and broad as to be essentially meaningless. For example, detox plans variously refer to refined sugar, caffeine, red meat, alcohol, gluten, and a host of environmental contaminants as toxins, and cite conditions as varied as obesity, fatigue, skin rashes, various cancers, bloating, depression, insomnia, joint pain, and chronic nasal congestion as evidence of “toxicity” in the body. Much detox lore is focused on the colon: toxic substances supposedly attach to and fester in the colon's lining, increasing the risk of illness unless they're removed via a special diet or, in some cases, enemas or colonic irrigation. (Both notions are false, and absurd. Your fecal matter does not harbor toxins that can make you ill; and cleansing your colon is unnecessary at best and dangerous at worse.)

Aren't the body's organs already designed to "detox" us, provided they're functioning properly?

Yes. In fact, viewed from this perspective, the human body is a marvelously efficient detoxing machine. The skin—your body’s largest organ—provides a barrier to harmful substances. Your airways trap and expel noxious particles, while your intestines screen out parasites and other harmful organisms while allowing nutrients to be absorbed into the blood. The liver acts as your body's primary filter, digesting food and ridding the body of toxic substances. Your kidneys also filter out toxins, via your urine. Those organs act in concert with the immune system to keep you well. Healthful eating, sleep, and exercise habits help the machine to run optimally; substandard ones compromise it. But there’s no evidence that a special detox diet or fast can take the place of or supplement what your own body is naturally programmed to do.

Are some detox diets or cleanses dangerous?

They can be—especially the more extreme or restrictive regimens. For instance, some detox plans eliminate critical nutrients, like protein, which can lead to malnutrition. A prolonged juice cleanse, also called a juice fast, over time could lead to an imbalance of electrolytes such as sodium and potassium. Other detoxing practices are even more perilous. Colonic irrigation, for example, is not only unnecessary (except as preparation for surgery or endoscopy), but can lead to serious complications, including diarrhea, life-threatening blood infections (septicemia), and perforation of the intestinal wall.

In addition, some groups are at special risk from extreme eating plans in general, including pregnant women, people with chronic conditions such as heart or kidney disease, and those with weakened immunity. They in particular should avoid any type of cleanse, purge, fast, or otherwise very restrictive diet.

Is there any scientific evidence to support detoxing?

There’s no evidence that any of these detoxing methods actually rid your body of harmful substances. (Your organs already do that, as discussed above.) And if your goal is weight loss—a benefit promised by most if not all detox plans—evidence suggests that detoxing can actually thwart your efforts in the long-term. That’s in part because, while the severe calorie restriction that most detox plans entail may make you thinner temporarily, the weight you’ll lose is mainly water weight—not body fat, the loss of which is essential in order to maintain weight loss over time. Indeed, studies have shown that both men and women who lose weight by fasting or dramatically reducing calorie intake routinely gain the weight back, and often end up even heavier.

What about drinking large amounts of water, as some detox plans advise? Is it true that can help "cleanse" the body or flush out toxins?

No. In fact, drinking a lot more water than is necessary to stay hydrated and quell thirst can impair the ability of the kidneys to properly exchange electrolytes, such as sodium, potassium, and chloride. That in turn can lead to potentially life-threating problems like cardiac arrhythmias. It might seem reasonable to assume that the more water you pour in to your body, the more bad stuff you flush out. But that's simply not the case. As long as you are producing light-yellow urine and don’t feel excessively thirsty, you are drinking all the water you need. (Note that elderly people often lose their thirst drive, so it’s important for them to remember to drink water or other fluid throughout the day. People with abnormal kidney function may also not be able to rely on thirst as an indicator of hydration.)

Bottom line:

Special detox plans are at best unnecessary and at worst potentially harmful. A massive body of scientific literature supports the effectiveness of a healthy diet, adequate sleep, and regular exercise in keeping your body’s systems functioning optimally—and in conferring the same results claimed by detox plans, like healthy-looking skin, sustainable weight loss, increased resistance to colds and other illnesses, and more. Save your money and put your energy instead into eating a well-balanced diet rich in fruits and vegetables, whole grains, lean protein, and healthful fats (such as nuts, avocados, and olive oil); living an active lifestyle; and making sure you get adequate sleep.