Do detox diets and cleanses work? What the evidence actually shows

Not in the way they are sold. Detox diets and juice cleanses promise to flush "toxins" from the body and reset your health, but the clinical evidence for those claims is close to non-existent — and the weight people lose during a cleanse is the transient result of eating almost nothing, not of any detoxification [s1][s2]. Your liver and kidneys already do the job these programmes claim to do, continuously and for free.

What "detox" promises, and what was tested

The detox industry markets a specific mechanism: that named products or juice regimens eliminate accumulated toxins and, as a side effect, promote weight loss and well-being. A 2015 critical review in the Journal of Human Nutrition and Dietetics set out to check whether any of that holds up, asking whether detox diets are necessary, what they involve, whether they work and whether they carry risks [s1].

Its central finding is how little there is to review. Despite a booming industry, the authors reported very little clinical evidence to support the use of these diets [s1]. The handful of clinical studies that do exist — showing that some commercial detox diets enhanced liver detoxification or helped eliminate persistent organic pollutants — were hampered by flawed methodologies and small sample sizes [s1]. There was preliminary evidence that certain foods, such as coriander, nori and the fat substitute olestra, have detoxification properties, but the majority of those studies were done in animals, not people [s1].

Most tellingly, the review found that, to the authors' knowledge, no randomised controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans [s1]. The single most influential product category in this corner of wellness has essentially never been tested in the way any medicine or meaningful health claim would require.

Why the scales move — and then move back

If a juice cleanse never removed a toxin, why does the number on the scale drop? Because the cleanse is a very-low-calorie diet wearing a different label. A 2017 review of popular weight-loss strategies looked at juicing and detox regimens alongside intermittent fasting, the paleo diet and high-intensity training, and reached a blunt conclusion [s2]. Juicing or detoxification diets tend to work because they lead to extremely low caloric intake for short periods of time — and they tend to lead to weight gain once a normal diet is resumed [s2]. Every one of the strategies it examined, the authors noted, is ultimately based on the concept of caloric restriction [s2].

That is the whole trick. Replace meals with juice for three days and you eat far fewer calories, so you lose some weight — much of it water and the contents of your gut — which returns as soon as you eat normally again. Nothing was detoxified; you were briefly underfed.

The organs that actually detoxify you

The premise behind cleanses is that toxins build up and need periodic flushing. In a healthy body they do not accumulate that way. The liver metabolises drugs, alcohol and metabolic waste; the kidneys filter the blood and excrete what is not needed; the gut, skin and lungs handle the rest. These systems run around the clock and are not switched on by a green juice or switched off by a normal diet. Where genuine poisoning occurs — heavy metals, certain drug overdoses — the treatment is specific medical care, not a supermarket cleanse.

There are downsides to the programmes themselves. Severe calorie restriction can cause fatigue, irritability and, repeated often, disordered eating; laxative- or diuretic-based "cleanses" can disturb fluids and electrolytes; and some detox supplements are unregulated and have been linked to harm [s1]. The review's real recommendation was not for consumers to try these diets but for researchers to study them properly, so that people can be told the actual benefits and risks [s1].

The bottom line

Do detox diets and cleanses work? For lasting toxin removal or weight control, no — the evidence is thin, mostly low-quality and, for commercial detox diets, missing the randomised trials entirely [s1]. Any short-term weight loss comes from eating almost nothing and reverses when you stop [s2]. If you want to support the body's own detox systems, the unglamorous answer is the durable one: don't smoke, drink little or no alcohol, stay hydrated, and eat enough fibre-rich food to keep things moving.

This article is informational and is not medical advice.

Sources

• Detox diets for toxin elimination and weight management: a critical review of the evidence — Journal of Human Nutrition and Dietetics, 2015
• Popular Weight Loss Strategies: a Review of Four Weight Loss Techniques — Current Gastroenterology Reports, 2017