Detox, detox, detox: that's January's unremitting mantra. Gwyneth's at it - "Just say no to: alcohol, caffeine, added sugar, gluten, dairy, soy, corn, and nightshades (potatoes, tomatoes, eggplant [aubergine])" - and so's Salma Hayek - "I've been doing cleanses for 15 years" - but can guzzling industrial quantities of liquid kale, deploying the word "purify" more frequently than John the Baptist, and booking into a colonic irrigation clinic really be beneficial for one's health?
We separate fact from fad.
Kara Rosen, founder of Plenish juices
Detox is a loaded word for many people, although it's not a product - it's a process. Most of us regularly consume an excess of processed foods, stimulants such as coffee and tea, alcohol and refined sugar. A lot of research points to how, in excess, these "everyday" substances can be as harmful as illegal drugs.
To detox is simply to abstain from consuming whatever harmful substance you're dealing with, allowing your digestive system to do what it is designed to do best.
On a Plenish cleanse, you abstain from eating processed and inflammatory foods such as dairy and meat, as well as stimulants (caffeine) and alcohol, for three days before your juices arrive.
Then comes the juice: by consuming raw, organic green juices while eliminating processed sugars, coffee, alcohol, meat and too much cooked food, you assist your system in becoming an oxygen-drenched alkaline one that will reduce inflammation and boost immunity.
Every person's needs are unique, but clients usually feel so much better after a cleanse that it inspires them to incorporate many more fresh, raw, organic vegetables and plant-based protein into their diet on a long-term basis - and this is where the life-long changes happen.
Ian Marber, nutrition therapist
My ongoing issue with the concept of the detox is that it doesn't exist. We aren't riddled with toxins, and the detoxification systems in place in the extraordinary human body do very well.
Year after year we are encouraged to cleanse, which has become shorthand for eating well.
If you look at the "detox" salads, juices, plans and recipes on offer from restaurants, they are nothing more than healthy, nutritious food. Fresh fruits and vegetables, good wholegrains, lean protein, nuts and seeds don't seem to be enough now.
Are we so childish that the benefits of a good diet need to be dressed up with marketing to persuade us to pay attention? If that's what it takes, so be it - but to my mind a decent diet all year beats a couple of weeks of sackcloth and green juice followed by retox and guilt.
Sian Porter, spokesperson for the British Dietetic Assocation
Detox diets are marketing myth, rather than nutritional reality. They sound like a great concept, and it would be fabulous if they really delivered all that they promised, but unfortunately, many of the claims made by detox diet promoters are exaggerated, and any benefit is short-lived.
Fasting, or severely restricting what you eat, limits intake of energy (calories) and important nutrients needed for health and wellbeing. Rapid weight loss can occur, but this weight loss is largely water and glycogen (the body's carbohydrate stores), rather than fat.
You may feel tired and dizzy and it's likely you'll have less energy while you are following an extreme programme. Furthermore, if you are fasting, your body won't have the necessary fuel available to carry out physical activity and exercise - an important aspect of general wellbeing and healthy weight management.
At the end of the programme, if you return to your old eating habits, you are likely to put back on any weight you lost.
While they may encourage some positive habits like eating more fruit and vegetables, it's best to enjoy a healthy, varied diet and active lifestyle, rather than following a detox diet.