UK dieticians have come out strongly against detox diets, championed by some celebrities, saying they are a waste of time and money.
The theory behind detox - that dangerous toxins build up in the body – has been dismissed by the health experts as pseudo-scientific. They have pointed out that the body is anyway constantly cleaning itself.
There is no "potion or lotion" which could "magically" rid the body of chemicals, the British Dietetic Association (BDA) has warned.
Thousands of slimmers are expected to try a detox diet in the next few weeks, spurred by guilt over heavy drinking and eating during the festive period.
A wide range of different kits, including ready-prepared vitamin drinks and diet plans, are available on the high street and from specialist health shops.
Dieters undergoing a detox are usually advised to cut out a wide range of "unhealthy" foods and supplement their diet with vitamin drinks. They are told that chemicals and other pollutants remain in our bodies over time, causing health problems, and need to be removed.
But Dr Frankie Phillips, a spokesperson for the BDA, said: "The whole idea of detox is nonsense.
"The body is a well-developed system that has its own built-in mechanisms to detoxify and remove waste from top to toe.
"Skin, the gut and liver and kidneys are all chemically-controlled powerhouses that respond to signals in the form of, for example, hormones, to remove waste products – typically detoxifying the body constantly.