Of course, the word “cleanse” has been applied to a huge range of diets, from those that replace one or two daily meals with fruit smoothies to the more extreme types that advocate drinking little more than spiced water for a week or longer. The extreme kind—those that could never permanently supplant a normal diet—don’t tend to have long-lasting effects.
Not only is the hard science on cleanse diets missing, but Dubost also says the premise underlying these drinks—that you can somehow flush your system of pollutants—doesn’t pass a basic sniff test. “Your body has built-in mechanisms for detoxification, including your liver, kidneys, and gastrointestinal system,” she says. “Swallowing some kind of solution isn’t going to further enable those organs, so the whole premise of detoxifying is inaccurate.”
Put another way, if you’re eating a healthy diet packed with fruits, vegetables, whole grains and lean protein—the kind of sustainable diet that will help keep your weight down and lower your risk for many diseases—your body has no use for any radical detoxification measures. And if your diet is poor, pounding juice for a week isn’t going to do you any good.
You’ll drop some water weight on these cleanses because you won’t be consuming very many calories,” Dubost says. “But that weight will come back when you start eating again.” The kind of severe calorie restriction associated with cleanse diets can also lead to muscle breakdown and feelings of extreme fatigue, as well as headaches, irritability, cramping and diarrhea.