I was on gliclizide for quite a few years, never put on weight in fact I lost 10st whilst on it, didn’t have an impact on my hunger levels either. You need to get your dose and carb level correct otherwise your feeding unnecessary hypos - this is probably where the weight gain thing comes from (in my opinion) I still ate low carb whilst on it - between 70 - 90g carb a day. I now only take metformin and do keto, great for my blood sugars but not my weight as have gained back 2 stone