Hi ShoppGirl, I replied to you in the DS forum. You'll probably find the answers you need in the Facebook group I'm in. It says it is for the Duodenal Switch, but we also have plenty of SADI patients in the group and we have veterans of both surgeries in there. https://www.facebook.com/groups/1799552573392212 I highly suggest joining that group and posting your questions.
Regarding gas, yes, the SADI can have gas issues if you eat too many simple carbs. And eating too much junk food may make your bathroom visits rather unpleasant. I had the DS done about 4.5 months ago and I don't usually have any gas issues and my bathroom visits are pretty normal except my stools are pale colored now due to the fat malabsorption (perfectly normal). But I stay below 50 total carbs per day and eat about 120 grams of protein a day and about 100 grams of fat. With the SADI or DS surgery you are more focused on your macros than calories because we malabsorb a portion of everything but simple carbs.
If you keep your carbs low after the SADI you will lose weight better and maintain weight better...and you should minimize the side effects. You'd also want to stay away from sugar alcohols and you might find that some foods digest differently, like lettuce or other leafy greens. Usually most SADI or DS patients learn within the first year what their trigger foods are and learn to eat them at home at night or not at all.