These promises sound scientific, but they don’t match what detox actually means. In medicine, detoxification refers to the removal of harmful substances from the body under controlled conditions, especially in the context of substance dependence or poisoning.

Outside of this context, the wellness industry has stretched the word to cover a wide range of practices and products that claim to rid the body of unspecified toxins. These claims are not supported by medical science.

Our bodies come with their own highly effective detoxification system. The liver and kidneys do most of the work.

When we eat or drink, nutrients and waste products enter the bloodstream and pass through the liver. The liver produces bile to help break down fats and remove toxins through faeces and urine

Blood then passes through the kidneys, where tiny filtering units called nephrons remove waste and excess substances, sending purified blood back into circulation.

Smaller amounts of waste are also removed through sweat, exhaled air and normal digestion. When this system fails, the effects are serious and obvious. People develop symptoms that require urgent medical care, not a special juice cleanse.

An issue with detox culture is that it could even encourage overconsumption, particularly of alcohol, in the hope that a post-binge cleanse will undo the damage.

The only reliable way to limit alcohol’s impact is to reduce how much we drink. No smoothie or detox drink reverses the effects of excess alcohol.

Detox approaches vary widely. Some are mostly harmless but unhelpful, while others carry real risks. The harmless group tends to rely on ideas that sound healthy at first glance but are not backed by good evidence.

Juice cleanses and liquid-only diets, for example, remove or break down a lot of the fibre from the fruit and vegetables. Some vitamins and antioxidant compounds are also lost, and the sugars become more rapidly available because the structure of the plant is broken down.

While drinking fruit and vegetables as a juice is better than not having them at all, eating whole fruits and vegetables tends to keep you fuller longer and provides more consistent nutritional benefits than drinking juice.

Lemon water is another common recommendation. It may taste sharp and refreshing, but it does not burn fat or remove toxins.

Detox teas are frequently marketed with added herbs or minerals. Some contain nutrients such as selenium, but these are already found in many everyday foods including seafood, poultry and nuts.

Many detox plans encourage cutting out alcohol and caffeine. Reducing alcohol intake has clear, well-established benefits for health, but cutting out coffee or tea entirely is unnecessary for most people.

Moderate caffeine intake, roughly three to four cups of coffee a day, can fit comfortably into a healthy diet and may even have some benefits.

Some detox practices move beyond being unhelpful and become dangerous. Excessive fluid intake is a feature of several detox regimes.

A case report described a woman who arrived at hospital with seizures after consuming large amounts of water and herbal remedies as part of a detox regime.

Her sodium levels had dropped sharply, a condition called hyponatraemia, caused by diluting the salts in the body faster than the kidneys could correct the balance.

Detox pills and powders can also pose risks, and their ingredients are not always clear.

Some herbal supplements marketed for cleansing or liver support have been associated with liver injury, such as products containing concentrated green tea extract, turmeric or complex herbal mixtures.

It is an unfortunate irony that these products can end up harming the very organ that performs most of the body’s detoxification.

So, is there any evidence to support a New Year’s detox diet? The short answer is no. Healthy liver and kidney function is sufficient to process everyday dietary intake.

When the body’s detox system fails, as in kidney failure, medical interventions such as dialysis (not lemon water or herbal drinks) are required.
For the rest of us, small, sustainable changes are far more effective than extreme short-term cleanses.

Starting a new eating pattern in January can be motivating, but drastic, restrictive routines are difficult to maintain.

Research shows that consistent, moderate changes, such as increasing fruit and vegetable intake, and reducing excess free sugar and alcohol support long-term health better than fad detoxes.

Ultimately, your body’s natural systems are remarkably efficient. Trusting them, and supporting them with everyday healthy choices, is far more effective than chasing the latest juice, powder, or tea.

A sustainable approach, rather than a radical reset, will serve your health best, not only in January, but all year long.

Rachel Woods is a  Senior Lecturer in Physiology at the University of Lincoln.