The lemon water diet, also known as the lemonade diet or master cleanse, involves drinking just a lemon juice mixture for several days to weeks while abstaining from solid food. Advocates of the diet claim that it can help detoxify the body, boost metabolism, and aid in weight loss. However, there is little scientific evidence to support these claims and some health experts suggest that the diet may be unhealthy and potentially dangerous due to its extremely low-calorie intake and lack of essential nutrients.