Is it healthy to do a body cleanse or do you just come back after the cleanse and gain weight more then when you started. ?

Not really: Any such approach where you lose a lot of weight in a short period of time is unlikely to be successful as since your body will only work that much harder to return you to your original "normal" weight. A slow steady weight loss will be more effective and you will need to work to maintain that for at least a year (probably longer) before your body will consider that new lower weight as normal