There is little evidence that detox diets or cleanses remove toxins or help long-term weight loss. A 2015 critical review found no randomised controlled trials of commercial detox diets in humans. Any quick weight drop mostly reflects eating very little and losing water, and it tends to return. Your liver and kidneys already do this job.
Key takeaways
- A 2015 review found very little clinical evidence for detox diets and no randomised trials of commercial programmes.
- Quick weight loss on a cleanse comes mainly from low calorie intake and water loss, and often returns.
- Juice cleanses, laxatives, colon cleansing and very low intake carry real risks for some people.
- The liver, kidneys, gut and lungs handle waste continuously; no product has been shown to improve on that in healthy people.
- Fibre, vegetables, water, sleep and less alcohol support health without a special programme.
What is a detox diet or cleanse?
"Detox" is a marketing term rather than a medical one. Detox diets and cleanses promise to flush "toxins" out of the body and often to kick-start weight loss. They come in many forms: several days of juices only, special teas, fasting with water or herbal infusions, lists of "clean" foods, supplements, laxatives or colon cleansing.
What they usually have in common is that they are short, restrictive and very low in calories, and that the "toxins" are rarely named or measured. In medicine, detoxification means treating poisoning or drug and alcohol dependence under clinical care, which is a different thing entirely.
What does the evidence say?
A 2015 critical review in the Journal of Human Nutrition and Dietetics (Klein and Kiat) looked at whether detox diets are necessary, what they involve, whether they work and whether they are safe. Its conclusions were clear:
- There is very little clinical evidence to support detox diets, even though the industry is booming.
- A handful of studies reported effects on liver detoxification or the removal of persistent pollutants, but they had flawed methods and small samples.
- Some foods, such as coriander and nori, showed possible effects, but mostly in animal studies.
- The authors found no randomised controlled trials testing commercial detox diets in humans.
The US National Center for Complementary and Integrative Health (NCCIH), part of the NIH, reaches a similar conclusion: the few studies that exist are of low quality, and there are no long-term studies.
| Common claim | What the evidence shows |
|---|---|
| "Flushes toxins out of your body" | No good-quality trials; toxins are rarely named or measured |
| "Kick-starts weight loss" | Short-term loss from very low intake and water; weight often returns |
| "Rests your digestive system" | No evidence that healthy digestion needs resting |
| "Boosts energy and clears skin" | Based on personal reports, not controlled studies |
Why do people lose weight on a cleanse?
Most cleanses provide far less energy than a normal day of eating, and often very little carbohydrate or protein. When you eat less carbohydrate, your body uses up stored glycogen, which is held with water. Less food in the gut and less salt also lower the number on the scale. The result can be a drop of a kilo or more in a few days that has little to do with body fat.
NCCIH notes that juicing and detox diets can cause quick initial weight loss because of low calorie intake, but that weight is often regained once normal eating resumes. Our guide to water weight vs fat loss explains why the scale can swing so fast in both directions. Real fat loss is slower: a gradual pace of about 0.5–1 kg (1–2 lb) a week is what the CDC suggests, and it is easier to keep off. See how fast you can safely lose weight.
Are detox diets and cleanses safe?
For a healthy adult, a day or two of juices is unlikely to cause harm, but some versions carry real risks. NCCIH highlights these:
- Unpasteurised juices can carry harmful bacteria, which is a particular concern for children, older adults and people with weakened immune systems.
- Juices made from high-oxalate foods such as spinach and beets may be a problem for people prone to kidney stones.
- Laxatives can cause diarrhoea, dehydration and poor nutrient absorption.
- Colon cleansing has little evidence of benefit and can have serious side effects, especially for people with bowel disease, previous bowel surgery, kidney disease or heart disease.
- Large amounts of water or herbal tea with little or no food for several days can cause dangerous electrolyte imbalances.
- Diabetes: people with diabetes should follow the eating plan agreed with their care team and talk to them before any major change.
US regulators (the FDA and FTC) have also acted against companies selling detox products that contained hidden ingredients or made false claims to treat diseases. If you are pregnant, under 18, take regular medication, or have a history of an eating disorder, talk to a doctor or registered dietitian before trying any restrictive plan.
How does your body actually remove waste?
Your body has its own, continuous detox system. The liver transforms many substances so they can be excreted; the kidneys filter the blood and remove waste in urine; the gut eliminates what is not absorbed; and the lungs breathe out carbon dioxide. These organs work all the time, not just during a cleanse. No juice, tea or supplement has been shown in good-quality trials to make them work better in healthy people.
What these organs do need is the basics: enough fluid, enough fibre, a varied diet, regular sleep, and not too much alcohol. If you have liver or kidney disease, that is a medical matter for your doctor, not something a product can fix.
What works better than a detox?
If what you want from a detox is a fresh start after a heavy period, such as holidays or a busy month, a few simple habits do more than any cleanse:
- Add vegetables and fibre rather than cutting whole food groups. Fibre supports regular digestion; see how much fibre you need.
- Drink water, and watch drinks with calories. Juices, sweet coffees and alcohol can add up fast; see liquid calories.
- Keep protein in every meal so you stay full and protect muscle while eating a little less.
- Cut back on alcohol for a few weeks if it has crept up.
- Return to regular meals and sleep. Routine does more for appetite than any reset.
Here is what a simple, balanced "after the holidays" day might look like. The numbers are Sporty's per-serving estimates; real values depend on recipe and portion.
| Meal | kcal | Protein |
|---|---|---|
| Oats, yogurt and fruit | 390 | 22 g |
| Red lentil soup | 250 | 13 g |
| Grilled fish and vegetables | 450 | 48 g |
| Shepherd's salad | 160 | 3 g |
| Yogurt and fruit | 230 | 16 g |
| Total | 1,480 | 102 g |
This day has real food, plenty of vegetables and protein, and fits a moderate deficit for many people (larger or more active people will need more). It will not feel as dramatic as a juice cleanse, but it is something you can repeat next week too. If you want to see where your calories actually come from after a heavy few weeks, logging meals in Sporty for a few days gives you a clear, judgement-free picture.
Frequently asked questions
Do detox teas work?
There is no good-quality evidence that detox teas remove toxins or cause lasting weight loss. Some contain laxatives, which can cause diarrhoea and dehydration, and regulators have acted against products with hidden ingredients.
Is a 3-day juice cleanse bad for you?
A short cleanse is unlikely to harm a healthy adult, but it provides little protein and the weight lost is mostly water. Unpasteurised juices and high-oxalate juices carry risks for some people, so check with a doctor if you have a medical condition.
How does the body detox naturally?
The liver, kidneys, gut and lungs remove waste continuously. Enough fluid, fibre, sleep and less alcohol support them; no detox product has been shown to improve on this in healthy people.
Why do I gain weight back after a cleanse?
Most of the early loss is water and stored glycogen, plus less food in the gut. When you eat normally again these return, which is why weight often comes back quickly.
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This article is general information, not medical advice. If you have a health condition, are pregnant or under 18, talk to a doctor or registered dietitian before changing your diet.