Thank you very much for your question, as it is a good one. The fat cells that are eliminated during a liposuction procedure will not return. However, if a patient should gain weight in the future, the surrounding fat cells can still expand. This means that liposuction results can be long-lasting, but the aesthetic benefits of treatment require a patient to continue with a healthy lifestyle. The fat cells that are transferred to the buttocks during a Brazilian Butt Lift are living tissue, and will be affected by weight fluctuations. I recommend that you schedule a consultation with a board certified plastic surgeon, experienced in BBL procedures. He/she can explain the procedure in detail, as well as show you before/after photographs of recent patients, giving you a better understanding of the liposuction and fat transfer process.