Studies have shown that patients lose 30-50% of their body fat within the first 6 months, and the next 12% tends to drop off after 12 months.
Further studies have shown that patients keep off over half of their weight loss for up to 15 years.
However, it's important to remember that after any kind of weight loss surgery, the patient has to maintain a healthy diet and regular exercise routine in order to aid and sustain weight loss - both initially and for an extended period of time post-op.