From insisting on purple-only foods to dosing themselves with a daily cocktail of slimming supplements, the A-list will go to any lengths to stay slender. Latterly though, the buzzword in Hollywood has been ‘detox’ with low-calorie detoxes seen as the perfect way to stay slim and get healthy at the same time. Everyone from Anne Hathaway to Gwyneth Paltrow and Madonna has bought into the trend but are these celeb detoxes really all they’re cracked up to be? The capacity to deal with periods of feast and famine has been hard-wired into our bodies by evolution, so theoretically, we should be able to cope with prolonged periods of low food-intake. But while nature meant prolonged to mean two to three days, low-food detoxes can be extended for far too long. So what are the secrets of a healthy detox? And, more importantly, how do you prevent something healthy from turning into something very dangerous indeed?

That detoxes can be healthy isn’t in doubt, particularly when it means you’re able to give your system a rest from unhealthy substances such as caffeine, alcohol and fat. “Our modern eating habits lead to a tendency towards ‘overnutrition’ which results in weight gain and stress on the organ systems having to handle the nutritional load coming in,” says Dr R N Phillips of the Synergy Integrated Medical Centre. “Detoxing helps the organs to eliminate and release toxins built up in the colon, kidney, bladder, lungs, liver and skin.” Detox specialist Michelle Reynolds agrees, adding that “it’s really important to detox in this day and age because the sort of lifestyle we lead leaves us feeling stressed out so we rely on convenience food. They tend to be loaded with E numbers and other toxins so detoxes and fasts are essential for eliminating them, and help rejuvenate the immune system, skin, liver, kidneys, lungs and colon which will leave you feeling a lot better.”

But while programmes promoting healthy eating and short fasts can be a positive experience, taking them too far and staying on them too long can be dangerous. With A-listers attempting ever more crazy detoxes, celebrities can have a baleful influence on detoxers. Take the lemonade cleanse for example. An extreme cleanse, it has become increasingly popular since being championed by the likes of Beyonce Knowles Anne Hathaway. But as it can last for anything up to 10 days and involves cutting out everything except a concoction made from water, lemon juice and maple syrup, it’s not for the faint-hearted. “Most women here are at all times either on a diet, thinking about one, reading about one or hearing about one their friends are on,” says Kathy Kaehler, a fitness and food coach based in L.A. who works with Julia Roberts among others. “But there’s a hitch. Even in this city, if you go on too many diets, your friends will start to think that you are vain, have an eating disorder or are just plain annoying. As a result, women here are—superficially, anyway—forswearing dieting and embracing a new euphemism for it: detoxing. Sure, you’re still expected to fit into those size 00 jeans, but instead of merely being super skinny, now you’re supposed to be skinny and healthy.” “Detoxing that is overdone can lead to water and electrolyte depletion resulting in weakness, lowered blood pressure, decreased resistance to infection and loss of energy,” warns Dr Phillips. “The decrease in urine production and increased urine concentration can make one more susceptible to kidney stones and to gout. Headaches, nausea and muscle weakness are also common complaints.”

So what does make for the perfect fast or detox? According to Michelle, there are five key foods to avoid during a detox: milk, caffeine, alcohol, anything containing ‘bad fats’ (such as meat and anything fried) and wheat. While a short 48 hour juice fast or similar can help kick-start a detox, they shouldn’t last any longer, and are no substitute for a healthy detox. Extremes clearly don’t work, so approach detoxing sensibly and you won’t go wrong. As clinical dietician, Nathalie Haddad of Right Bite says: “You need to make good habits from the start to prevent weight-gain and to promote good health, and that means things like fruit and vegetables, lots of water and plenty of exercise.” While short fasts and detoxes can have a place in a healthy way of life, going to crazy extremes does not.