Hi Brummy,
There are a lot of people with that issue, me included.
I've never been skinny, but since the ileostomy in 2018/2019 up until this year, I gained 33 kg. I went to multiple nutritionists, personal trainers, etc. I even overdid it and got a ruptured bowel and parastomal hernia. But nothing worked.
My surgeon suggested weight loss surgery since Ozempic and other weight loss medications weren't suitable for me (pancreatic inflammation in the past due to Imuran).
So last April, I had a gastric sleeve, and so far, I have lost 24.7 kg. I hope to lose another 15 kg if possible, but I will see what my body wants to do.
The sleeve doesn't affect my output, and it doesn't affect my Crohn's. I have never been hungry since the surgery. Bariatric surgery is not the easy way out, as many people believe, but it is a last resort option if you have tried everything else and it didn't give results.