It has long been believed starting the day with hot or warm water with lemon is a great way to rid the body of toxins.
Health gurus have spoken at length about how the fruit's juice stimulates the liver to flush out waste.
But now a scientist has branded this a myth - he says in medical terms, there's no such thing as "detoxing". It's nonsense, according to Daily Mail.
"There is no evidence that these drinks will do anything to toxins," Dr Ian Musgrave, molecular pharmacologist and toxicologist at the University of Adelaide, told Coach.
"But it's certainly tastier than warm water alone."
He also said the drink will rehydrate you, increase vitamin C level and may reduce your calorie intake if used as part of a fast.
But he branded fast and cleanse diets as "fads" and said people too often binge on food or alcohol after the "cleanse" is over.
"Sensible long-term changes to diet and exercise outweigh any purported benefits of 'detoxing,'" he said.
WHY DON'T CLEANSES WORK
Dr Musgrave argues that "detoxing" products are misleading marketing scams.
He says that the body does have toxins. Indeed, experts say exposure to these have increased with our modern lifestyles.
We absorb chemicals from pesticides cosmetics, body care products and plastic food and beverage packaging. And industrial waste contaminates soil and water that permeate our agriculture products and seafood.
But our body alone is capable of getting rid of these toxins.
"[The liver] is packed full of enzymes that specifically break down xenobiotics so they are no longer toxic, and the breakdown products are readily excreted," explained Dr Musgrave.
"Once the liver has converted a xenobiotic to a water-soluble compound, this is excreted by the kidney or secreted into the bile."
The scientist also said the idea that toxins "build-up" in our bodies over time - weeks, months or years - is rubbish.
In fact, the body's own natural detox process is extremely fast.
"There's a popular idea of toxins 'building up', but generally no, this doesn't happen," he said.
"For the majority of compounds the removal of these toxicants is very rapid.
"For some fat-soluble compounds, if the intake is faster than metabolism, then they will build up in the fat - but no amount of juice or sweating will remove them."
DETOX DIETS ENDORSED BY CELEBRITIES
The Master Cleanse: While the Master Cleanse has been around for decades, it is Beyoncé who allegedly made it mainstream. It is claimed she used the diet to slim down for her role in Dreamgirls. It involves drinking a concoction of lemon water, maple syrup, and cayenne pepper, along with an herbal detox tea, daily for at least 10 days - and nothing else. While it may work in the short term, experts say it isn't safe long-term. And even Miss B said it was "awful" and made her "cranky."
Juicing: Juice cleanses are a multi-billion dollar industry crammed with expensive 'detox' bottles of pureed vegetables and fruits who have attracted a fair share of celebrity devotees including Carol Vorderman. Juice cleanses - of which there are many different types - promise a vitamin mega-dose by having people replace all (or part) of their solid food with specially formulated juices. But experts warn that many juices are high in sugar and lack the fibre that whole fruit has. While short cleanses may not necessarily be harmful, longer detox can be dangerous - especially for people with medical conditions, pregnant women or the elderly.
The Alkaline Detox Diet: Stars including Gwyneth Paltrow and Elle MacPherson have reportedly embraced the fad over the years. Alkaliners say we eat too many 'acid-forming' foods - wheat, dairy, meat, seafood, sugar, coffee, tea, fizzy drinks and alcohol. This they say causes a pH imbalance which apparently disrupts the body's ability to regulate itself - leading to problems such as low energy, poor memory, headaches and bloating. Alkaline foods - fresh fruit, vegetables, nuts, legumes and wholegrains - help to restore the body's pH balance. But experts warn that when you cut out entire food groups such as dairy products, meat and fish, you leave yourself in danger of real deficiencies.