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Why Detox Diets and Cleanses Always Fail

If you spent any part of this month on a cleanse or detox diet, at some point in the process you likely felt run-down, irritable, depressed, nauseous, or fixated on food. Maybe you also experienced headaches, diarrhea, or dizziness that was enough to make you want to give up. The makers of these programs often prepare you for some unpleasantness, of course: Since you’re cleansing your body of all the “toxic” substances you previously absorbed, they say, you’ll feel the nasty effects of those “impurities” leaving your system. That’s why you spent two days dry-heaving, right?


You felt like crap because you likely weren’t eating enough — plain and simple. And now, despite what the pseudoscience-loving creators of these diet plans would like you to believe, you’re not in better shape. Perhaps you lost some weight, but it’s mostly water weight plus muscle loss — so now you're weaker than you were before, and you've changed your body composition for the worse. Because muscle burns energy even when you're at rest, muscle loss slows down your metabolic rate. And then on top of that, you might also still be feeling annoying symptoms like fatigue, headaches, nausea, and brain fog — some of the very same things these programs promise to cure — brought on by the diet itself.

If that's not enough to make you toss those overpriced bottles straight into the recycling bin, read on to learn more about the real deal on cleanses.

This Is Your Body On A Cleanse

The terms “cleanse” and “detox” are used pretty much interchangeably, and the programs they refer to can take many forms. Some of the most popular ones are regimens centering around juices or smoothies with little or no solid food, or diets in which a wide range of supposedly toxic foods are eliminated. Marketers of detoxes and cleanses almost never provide any scientific rationale for why these foods are considered toxic, which is the first clue that there’s something fishy going on here. Given that there are millions of peer-reviewed studies of actual toxic substances, the fact that detox and cleanse companies can’t offer any sound science is a big red flag.

The foods that are most commonly pinpointed for adding to the body’s “toxic load” include dairy, gluten containing grains, coffee, alcohol, and red meat. But even certain fruits and vegetables, including tomatoes, peppers, and eggplant, are eliminated on some detox plans because they are (mistakenly) said to cause inflammation. Cleanses and detoxes often promise to “give your body a break” from processing all these "toxins."

The main issue with these kinds of plans is that they essentially advocate starving the body of the fuel it needs. This leads to a drop in blood sugar, which the body attempts to correct by releasing a reserve of glucose called glycogen from the muscles. (Glycogen, by the way, is bound up with water, so releasing it causes the water weight losses typically seen on a cleanse or detox). But prolonged starvation can lead to hypoglycemia, which is potentially dangerous low blood sugar that can cause anxiety, dizziness, nausea, fatigue, and confusion. If you have caffeine withdrawal on top of that, many of those symptoms will be compounded, and you might also have headaches and nausea.

Makers of detox and cleanse programs attribute these symptoms to the toxins being eliminated from the body, which they say have accumulated in the digestive organs, liver, and kidneys from eating and drinking too many of the “wrong” things; some programs also promise to eliminate stored environmental toxins like pesticides and heavy metals. But this is a bunch of baloney.

The organs in your body that process waste and filter out toxins don’t need to be “cleansed” — they are self-cleaning. Your liver and kidneys aren’t like filters in the sink that get clogged up with gunk; they’re more like a complex wastewater processing facility that uses chemicals to neutralize and clear out toxic compounds. Unless you have liver or kidney disease, or an acute case of poisoning, these organs function just fine without any outside intervention.

Your liver and kidneys aren’t like filters in the sink that get clogged up with gunk.

The same goes for your intestines. In the absence of a true intestinal disorder or disease (such as Crohn’s disease or diverticulitis), there is no more need to “rest” the gut than there is to “rest” the heart or lungs. In fact, the gastrointestinal tract functions best when it’s being used; diets without adequate calories or solid food can cause slowed digestion and constipation. And forget colon cleansing, which is part of some detox or cleanse programs. It has no proven benefits and may cause serious complications for some.

In reality, no rigorous clinical trials of detox diets or cleanses have been conducted to date. The few studies that exist have major methodological flaws — biased samples and tiny sample sizes, reliance on self-report, no control groups, or the use of animals instead of human subjects — making it impossible to rely on their results. There just isn't any good science that supports doing a detox or cleanse. (Note: This type of detox is not to be confused with drug and alcohol detox programs, or detoxification from actual poisoning, both of which are supported by research.)

Some proponents of cleanses and detox diets — unfortunately including some of my fellow dietitians and nutritionists — argue that even if these programs aren’t really flushing out toxins, they can still be a way to “reset” or “jump-start” healthier food choices going forward. In reality, these diets do quite the opposite: By causing food deprivation, detoxes and cleanses actually set you up to overeat when you finally do get back to your regular diet.

Speaking of which, if you have a history of eating disorders or risky weight-control measures, detoxes and cleanses can be a major trigger for relapse. Most women in the U.S. have engaged in some unhealthy dieting practices, but even for people who haven’t, starting a restrictive diet like a detox or cleanse can actually be the spark that sets off an eating disorder. In addition, because of their effects on blood sugar and electrolyte levels, very restrictive detoxes and cleanses can be risky for people with diabetes, heart problems, or kidney disorders, as well as for pregnant or nursing women.

The Real Way To Get On Track

What should you do instead of a detox or cleanse? The best advice is to follow sensible nutrition guidelines most of the time: Eat plenty of plant-based foods and lean protein (but preferably not under the judgmental banner of “clean eating”). Honor your hunger and fullness cues, which will probably mean having several snacks in addition to three meals a day (and may also mean taking home doggie bags from restaurants rather than cleaning your plate). Try cooking more meals at home, this helps reduce your sodium intake as well as your spending.

And finally, ditch the diet mentality, which is just as present in the holistic wellness world as it is in more mainstream circles, if perhaps more subtly. Instead, practice intuitive eating, which can help you develop a healthy philosophy around food and eating, rather than a diet that sets you up to fail. Eating intuitively means giving up deprivation in favor of a normal, peaceful way of thinking about nourishing your body. Not only will this kind of plan help you feel less crazy, but it also has been linked to better health outcomes (including lower BMI, fraught as that metric is) than even the most gentle diet.

The bottom line: The only thing your cleanse is truly clearing out is cash from your wallet. There's a better way.

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