The Master Cleanse (or Lemonade Diet) has been around for quite some time, but gained popularity a couple years ago when Beyonce reported substantial weight loss in a short amount of time from this method. While it was originally intended for use as a full body toxin cleanse, it has grown into something people use for fast weight loss. While on the cleanse you are limited to drinking the "Master Elixir" (lemon juice, cayenne pepper, maple syrup, and water), a mixture of water and sea salt, herbal laxative tea, or just plain water. Sounds delicious AND nutritious right?
Obviously while on this diet (anywhere from 4-14 days is suggested) you lose weight because your calorie intake is so low. You are barely getting enough nutrients to keep your body running and, because of this, may experience headaches, dizziness, fatigue, nausea, and constipation. Your metabolism will slow because your body is starving, which will make it easier to gain all the weight (and then some) back once the cleanse is over. This creates a vicious cycle and often leads to feelings of guilt because even after "all that work" you still managed gain the weight back.
There is no evidence to support the fact that you need a cleanse to get rid of the toxins in your body. Your liver is doing that for you. The best you can do to keep your body healthy and fit is eat foods high in nutrients that you need, have a balanced diet (which can include an unhealthy snack or two), and stay physically active. One of the last things most of us want to do is slow down our metabolism, which is exactly what a starvation diet does. Extraordinary claims and anecdotal evidence make for a great fairytale weight loss plan, but don't do much for those actually looking to lose weight.