What are the risks involved in having obesity surgery?

Depends: There are a lot of different types of obesity surgeries. It all depends on which ones, what other medical conditions one has, the psychological health of the patient, the support system, and the patient's motivation.

Varies by procedure : Always consider risks and benefits. For band, risk of slip (2%), erosion (1%), removal (25%). For sleeve, risk of leak (1%), acid reflux & heartburn (8%). For bypass , risk of leak (0.5%), ulcer (1%), stricture (4%), obstruction (1%). For all, risk of gallstones (5%), temporary bleeding 1%, leg/lung clot 1%. Overall, all are about as safe as taking out appendix. Most complications can be treated.