Bariatric Surgery and Swimming

I am wondering if anyone among the USMS swimming ranks has had experience with bariatric surgery. Did this lead to sustained significant weight loss? Did it have a positive impact on your swimming and/or other aspects of your health? Did it help your speed, endurance, or both? Did it help one stroke more than others? It's also conceivable that such surgery has had neutral only, or even negative, impacts on your swimming performance. If so, what problems has the surgery brought you? Does reduced caloric intake, for instance, make it hard to train as hard as before? If you have shed very significant amounts of weight, have you needed follow-up procedures to reduce loose skin, or does this tend to contract naturally over time? I have a friend who was a great swimmer in college who I think could benefit from this approach, but he is very reluctant to try it, opting to go the natural route (lifestyle and diet modification only). The problem, however, is that though this has proven somewhat helpful, he still needs to lose very significant amounts of weight, and he's reached a plateau. I am thinking that the combination of the surgery AND continued diet and swimming practice will lead to a positive spiral upwards--the more weight he loses, the better his swimming will become, which reinforces the diet and commitment to swimming even more. Is this naive? I am hoping someone who has been through the process can provide some insights! Thanks! PS if you have had the surgery, is there any specific type you would recommend? I have heard that the "sleeve" procedure might avoid some of the nutrient absorption problems of earlier techniques. The removable "balloon" also seems intriguing because of its reversibility. Thanks!