Does detoxing work?

Juice fasts, liver detoxes and colon cleanses may seem like a great way to kick start a healthy lifestyle—but are the claims surrounding them true?
Published 10 February 2021 | Updated 1 July 2024

Detoxing: Fact or fiction?

It sounds like a great plan. After partying during the festive season you’re keen to make a fresh start in the New Year. So you decide to go on a detox which, as most of these things claim, will rid your body of toxins and have you feeling great in no time.

The trouble is that extreme detox diets—everything from juice fasts to purges, liver detoxes and colon cleanses—don’t work. Despite the amazing claims, there’s no scientific evidence to show that we need to follow a special diet to help our body remove toxins.

Here we look at some of the most common beliefs about detoxing and separate fact from fiction.

What is a detox?

Detoxification or ‘detox’ diets are short-term interventions designed to eliminate toxins from the body and promote health. They can range from a simple diet of raw vegetables and unprocessed foods to more restrictive liquid-only diets such as juice cleanses and lemon water detoxes.

‘Toxin’ is a much harder term to define. Traditionally it refers to alcohol and drugs but these days it’s come to include sugar, saturated fats, caffeine, carbohydrates and environmental pollutants.

Fiction: Detoxing flushes toxins from the body

The idea that detox diets eliminate toxins from the body isn't backed by science, says Dr Tim Crowe, an associate professor in nutrition at La Trobe University. Why? Because the body already does the job for you.

“We’ve got a really well functioning body that’s designed to remove all sorts of toxins and waste products,” he says. “That’s what our kidneys, lungs, immune system, gut and liver do—and they do it extremely well.”

Indeed, a review of popular detox diets published in the Journal of Human Nutrition and Dietetics found that there’s no compelling evidence to support the use of detox diets for toxin elimination.

“The human body has evolved highly sophisticated mechanisms for eliminating toxins and there is no detox diet that has been shown to confer long-term health,” says Professor Hosen Kiat from The Australian School of Advanced Medicine at Macquarie University.

And the same goes for colon cleanses. A review of the literature published in the American Journal of Gastroenterology found no evidence to support the use of colonic therapy for digestive health.

Fact: Detoxing can slow your metabolism

Many detox diets require you to eat a lot less food than you usually would—or, in the case of some toxin cleanses like a juice detox, no food at all—which can cause your metabolic rate to slow.

There’s limited research examining detoxes but studies looking at fasts and extremely low-kilojoule diets have found they may lower the body’s basal metabolic rate as it struggles, faced with such a dramatic energy deficit, to conserve energy.

The trouble with many detoxes is they don’t include protein, says Melanie McGrice, an accredited practising dietitian and spokesperson for the Dietitians Association of Australia.

“If you’re doing a juice cleanse, for example, sometimes they don’t include any protein,” she says. “You can lose muscle mass as a result, which can slow down your metabolism and make it harder to maintain a healthy weight in the future.”

“Weight loss from detoxing is usually temporary and the result of a loss of water instead of body fat”

Fiction: Detoxing is an effective quick fix for weight loss

While detox diets can result in weight loss, Dr Crowe says this likely has nothing to do with the removal of toxins—and the weight is usually regained once you revert to your normal eating pattern.

“A detox diet is usually a very restrictive way of eating for a short period of time,” he says. “Any weight loss is usually temporary and the result of a loss of water and glycogen instead of body fat. Eventually you’ll return to your regular way of eating so detoxes are not a long-term solution for losing weight.”

Instead, he says long-term lifestyle changes, like eating plenty of healthy foods every day, are the key to managing a healthy weight.

Fiction: Detoxing makes you feel good

Despite claims to the contrary, because many detoxes eliminate whole food groups, they can leave you feeling tired and lacking energy. “Often you’re not giving your body any nourishment and you’re missing out on key nutrients,” says McGrice. “You might not be getting enough iron, for example, and low iron is well known for reducing energy levels.”

Other potential side-effects can include low blood sugar, muscle aches, dizziness and nausea. And this isn't because your body is detoxifying. “It’s a sign your body has gone into starvation mode,” says Dr Crowe.

But if your idea of a detox is cutting back on alcohol, sweets and deep-fried foods, McGrice says this can help to boost your energy. “There’s certainly nothing wrong with doing a detox where you decide to reduce alcohol, sugar and fried food,” she says.

Fact: Some detoxes can be dangerous

Detox diets that promote extreme fasting are especially worrying as they increase the risk of protein and vitamin deficiencies, electrolyte imbalances and stomach and bowel upsets.

“In assessing one detox diet we found that, based on the average person’s minimum daily energy requirement, it does not meet daily protein requirements for anyone who weighs more than 23kg,” says Professor Kiat. Colon cleansing (aka colonic irrigation or colon hydrotherapy), too, can be risky. Mild side effects like cramping and bloating are common, and more serious side effects include infection and bowel perforation.

“Colon cleanses can be dangerous as you can be moving bacteria into places it shouldn't go,” says McGrice. “You’re better off eating a diet that’s high in fibre—that is, plenty of fruits and vegetables, legumes and grains, and drinking plenty of water—to optimise your digestive system and colon.”