"Cleansing the body" of toxins is a common theme in alternative health circles. Sometimes, what is meant by this is that you eat a restricted diet (such as just fruit or vegetable juices) for a while. Other times, 'cleansing' may also include a purge, designed to clean out your colon.
Generally speaking, there is no scientific evidence that any of these methods or approaches have any significant health benefits. In general, it is best to avoid any extreme diets, such as an all-juice diet. These extreme diets do not help you reinforce overall healthy eating habits for life and, in some people with chronic medical problems, they may actually be dangerous.
Similarly, colonic or intestinal purging doesn't have any health benefits, and it may be dangerous, especially in the elderly or in those with kidney or heart problems, as it could lead to extreme shifts in blood chemistry or fluid shifts.
It would be best in this situation instead to make an appointment with a dietitian
or with your primary care doctor
. They can discuss potential healthy eating plans with you and help you meet your diet and exercise goals through the development of a realistic and safe approach.